View allAll Photos Tagged Predict
Predicting your call on the extra board can be a bit like long division, needlessly complicated and never really sure you got it right... until the phone rings. Today I thought I had it all dialed in, a phosphate train off the CSX coming north on the Superior Sub was showing ordered for 1230 out of Pokegama with no north pools available for several hours, got it. Just before that call was expected to come in, the phone rang. CN Crew Caller... well shit. “Mr Hennessy are you qualified on the T-Bird?” Yes. Yes I am. So off to Keenan I went. Left a little early in hopes of catching some iron ore action, timing was great as I paced a northbound limestone train from Alborn up to the range, unfortunately the sun was shit for northbound moves. Coming up to Fairlane I spied a load of pellets ready to head south, hedging my bets that he would get the light clearing the limestone train I parked. Sure enough the limestone blazed past and the pellet loader was headed to the docks in Duluth. These standard cab dash 8’s hold a special place in my heart as I made my first solo run as an engineer in one (CN 2019) on a Q119 several years prior. Most fans up here loath the toasters and covet the sd40’s, a sentiment I certainly understand but anywhere else in the country finding standard cab dash 8’a leading trains in 2021 would be constitute a miracle from christ himself... on the range, just another reason not to take the lens cap off. I should get out more often to shoot these dinosaurs, but CN is very good at finding ways to occupy my time and my daughters take up the rest. These old GE’s may have another couple years left in them but the kids only stay 5 and 3 for another couple months. Priorities... It does make me appreciate the rare moments trackside that I have however!
as predicted three days ago, odin's cousin is coming tonight!
ruby, the little fairy princess, decides to help things along with a belly touch and wave of her wand ( unfortunately out of the picture frame ).
stay tuned!
boy, this should really help the sweeps week ratings for the snowdeal show ®.
see also here for more of the hour-to-hour details.
Still waiting . . .
The label at the historical society in Astoria, Oregon, didn't explain what was behind this astonishing chamber-of-commerce style flight of fancy. I have a feeling it was the grandiose idea of a local political candidate with the surname Jackson.
Clatsop County Historical Society, Astoria, Oregon.
They predicted a big storm here in Sweden for last weekend. This was taken on friday, the day before. And it was really calm out there on the sea.
This is straight out of Woo Woo land...
I was in college on a Geography Club field trip somewhere in Maine in 1957, when our group came upon this bit of graffiti. I (Roger) had a female friend who I called Sam (later softened to Sammy). We were classmates but were definitely not "an item," had never gone out on a date together, and in fact, at that time, Sam thought of me more as a pest than a friend. Obviously, the creator of this graffiti had someone other than us in mind, but all the guys and gals on that field trip decided he was psychic and that my destiny had been sealed. Turns out he was right... Poor Sam was very upset that I had taken this photo and shown it to fellow classmates. The thought of us in any kind of a "relationship" was downright repulsive to her, and she didn't find this in the least bit funny and certainly not even remotely predictive of the future.
We were married three years later...
Copyright - All Rights Reserved - Black Diamond Images
As the predicted Omicron Covid outbreak in December 2021 was about to go rogue the Perrotett NSW government removed most restrictions. Public and business backlash saw the NSW Government quickly reinstate some of the previously existing restrictions, like mask wearing in public spaces. Common sense was sadly lacking because the initial relaxation made no sense at all yet was hardly surprising given the abominable manner in which the NSW Government handled the Ruby Princess debacle as well as the June 2020 Bondi Junction outbreak.
At the same time as Omicron was arriving on the scene support services for contact tracing and PCR testing were being wound back and the Federal Government said they would not fund subsidization of Rapid Antigen tests (RAT) probably because they did not want to undercut their donors, among them Chemist Warehouse and Harvey Norman. Electrical goods and furniture retailer Harvey Norman, was very likely tipped off as to the government's intended policy, or indeed they lobbied for it, and immediately ordered many thousands of the Rapid Antigen tests which are now being sold. At the time of writing (5.1.21) online ordering of RAT tests via Chemist Warehouse yielded a nil result with tests out of stock as is the case, as I write, with most pharmacies and supermarkets. Some of those commercial sales outlets with stock have been guilty of price gouging with prices as high as $40 for a single test. The tests actually cost under $4 each to produce and the manufacturers say they can produce 15 million tests in a day.
The current dire shortage of tests is a legacy of callous and indifferent, if not incompetent management, by the Federal Government who failed to heed warnings issued by the Australian Medical Association in September 2020 that RAT tests would be an essential tool in managing the predicted tsunami of infections to occur from January 2022. Most health experts are of the belief that the Federal Government should be making the RAT tests free as a means to help minimize the impacts of the predicted explosion in cases of Omicron covid.
Are you looking to buy a RAT test in Australia or can you confirm via this site a business that is selling them - Try this site FindaRAT
Around 74% of the current NSW Covid ICU cases are of the Delta variant indicating that since Perrotett removed most restrictions before Xmas 2021 Delta has become rampant in the community. The situation is made much worse because the government has stopped tracking infections and our political leaders are selling the message that Omicron is the problem and it's less virulent, deflecting from the impacts of Delta which for now is much more problematic.
We have here a massive case of political failure to protect the Australian people. One could only imagine what would have happened if condoms had been made so ridiculously expensive during the AIDS crisis from 1981 onwards.
Chaos is increasingly the state of play in the NSW health system as hospitals begin to struggle with a lack of staff and rising Covid admissions which are detrimentally impacting on the opportunity for other urgent life-threatening procedures. Health workers are even being pressured by hospital administrators to come back to work even though they have Covid 19.
On the 5th Jan 2022 NSW recorded 35,054 cases a day but this is not an accurate assessment as it has become very difficult to be tested if an individual feels they have been exposed or have symptoms. The actual infection figures are likely to be up to 10 times higher according to some experts. People, some with Covid symptoms, are lining up at testing centres for up to 7 hours to get tested. It should come as no surprise that many just give up waiting. Drive through queuing is of a similar wait time. Many testing laboratories have become overwhelmed and understaffed due to some staff becoming infected with covid rendering them unable to work. For these reasons the labs are unable to return test results in a timely manner. Some tests results appear to be taking 4-7 days to be returned and there are almost no RAT tests available to buy anywhere in NSW.
The shambolic mismanagement by the Perrotett and Morrison Governments is there for all to see. Both governments, imbued with a business first ideology (or should that read donors first) are of the mindset to 'let it rip' and this ideologically driven approach has seen the virus escalate its intrusion into all other states of Australia, despite their best efforts to keep it at bay.
The failure to manage this health crisis appropriately is not only impacting people's lives and health but in fact doing immense damage to the bottom line of many businesses as well as the economy.
It might seem like I am stating the obvious when I say it's very unwise to catch covid yet many people appear to be confident in their trust in the effectiveness of triple dose vaccination. Hopefully this trust is proven to be correct in the coming months.
From my own limited observations, it appears some people out there on the streets are naively unconcerned about the risks to their own, or their family's well-being, believing they will catch covid, Delta or Omicron, eventually and that they'll survive it.
If Seal Rocks was any example on Boxing Day 2021 there are plenty of people in that category. I've never seen so many cars lining every road, occupying every parking space and indeed many illegal ones. It was 'wall to wall' people, like I'd never seen before.
Despite these crowds my solitary walk through the rainforest brought me out at the southern end of Number 1 Beach from where I took this shot. Most people had located themselves on the beach further north from this point while many had returned to their cars for lunch. To be fair though it was clear that many people were social distancing from strangers but not necessarily in their family groups.
As we enter 2022 the game is changing rapidly, the 'let it rip brigade' appear to have won the war, for now, at least in NSW.
It has been reported that Omicron may well be more infectious but the jury is still out as to whether it's as potent as Delta. Even if Omicron turns out to be less potent the sheer growth in Omicron infections to come may yet result in significant growth in ICU admissions and potentially, in more deaths.
With many children going back to school in a few weeks not having had their 2nd jab, let alone their boosters it appears 2022 is going to be one big game of Russian Roulette.
The ship is rudderless so good luck folks.
Please consider joining and adding your Handheld Panorama Photos to the Group - HANDHELD PANORAMAS
"Only two things are infinite, the universe and human stupidity, and I'm not sure about the former.!
Albert Einstein
I really think you should View On Black
While predicting where the birds will overnight on this refuge is an iffy proposition, this shallow lake just off the tour-route road is a regular hangout. The trick is to check it out early to see if any pathfinder birds have already selected it. If so, they will continually vocalize to the overflying birds trying to entice them to drop down and join them (increasing safety in numbers). There are several blinds here that you can select for different vantage positions. It's still early, and this lake was eventually completely filled with overnighting birds.
IMG_4248; Sandhill Cranes
I'm best at predicting the old year, she said, and; you'd be surprised how many people are even sceptical about that
♥♥♥ ♥♥♥ ♥♥♥ ♥♥♥ ♥♥♥ ♥♥♥ ♥♥♥ ♥♥♥ ♥♥♥ ♥♥♥ ♥♥♥ ♥♥♥ ♥♥♥
We sat side by side in the morning light and looked out at the future together
both (storypeople)
Goes down well with a ♪♪♫♪♪♫ note ♪♪♫♪♪♫ of sweet words....
♪♪♫♪♪♫ You are the NEW DAY ♪♪♫♪♪♫
Thank You! (King's Singers)
The BEST New Year's Concert ever..... LOL:
I have received SO many Jacquie Lawson cards this Christmas AND for New Year that I can't stop smiling....
I MUST now get my own subscription! They are just TOO ENCHANTING....
Thank you all dear friends - you picked up the discreetest hint and delighted me with many, many wonderful cards, messages, songs, lines, photos and mails, private and officially.
May God bless you for every kindness you offered - to me and to anybody out there.... May you be rewarded with serenity, joy, and friendship in return and may your 2010 be a richly filled and happy one!
Kiki
© All rights reserved
Kindly visit my Flickr DNA for more information on me and my work. Thanks!
*♥* ♥ - LOVE - friends - ♥ :) *♥* MOST INTERESTING *♥*
*♥* MY personal 50 FAVES *♥* SQUARE *♥* -25 FAVES *♥* Christmas Season *♥*
It was a cool, overcast spring day in Toronto. With rain and showers predicted for all day, it was too wet to encourage me out for a bike ride or a photo walk. The rain paused long enough near noon that I went out to pick up a couple of items at the grocery store and I carried my camera “just in case.” “Just in case” happened as I was crossing the street and it took the form of this attractive young woman with an explosion of blond curls. We passed one another as we were crossing the street and I turned on my heel to catch up with her on the sidewalk before she reached the subway station. I thought she might be ignoring my introduction and request but she was just tuned into her earbuds. When she realized I was talking to her, she pulled an earbud out and listened with interest. She said she would take a few minutes to participate in my Human Family photo project. Meet Yori. I asked about the origin of her name and she said her father told her it has its origins in Jerusalem. Google told me that one version of Yori has Japanese roots and means “reliable.” There are also some references to Hebrew versions.
My challenge was to come up with a suitable location to photograph Yori, given that we were on a busy streetcorner with only a bank and the subway station – both of which were rather unappealing. Between the two buildings was a small alley with a fence at the back. The dark, wet wood of the fence had potential, but it was complicated by a parked car and No Loitering and No Smoking signs. These are the challenges of doing street portraits.
I squeezed Yori and myself between the parked car and the fence and worked to avoid the signs on the fence. My first test shot had to be taken quite close in because of the confined space and although I was very happy with it, Yori surprised me by saying she didn’t like it at all. The same thing happened with my next couple of attempts. I tried to understand what would make her feel better about the photos and we ended up with me leaning back over the wet hood of the car to get a bit more distance. I had to laugh at the spectacle me and my gymnastics must have been presenting to anyone passing by on their way to the subway. To finish painting the scene, city buses were idling noisily to my left as they prepared to leave the station and they were belching diesel exhaust. I had little choice but to plunge forward because I could see that Yori was an excellent subject. Oh, and did I mention the smear of pigeon poop on the fence? I assured her that I could remove that later with Photoshop.
As I was giving Yori a bit of direction regarding looking at the camera, she adjusted the zipper on her jacket and I told her the inclusion of her hands would add to the photo. I took a photo of her with her hands on the zipper and I liked it. Suddenly she said “I have an idea, can I just do my own posing?” I said “Of course you can. If you have an idea, go for it.” To my surprise, she removed her backpack and started shedding her coat. I was concerned about her things getting wet on the ground but she was a young woman on a mission and who was I to interfere. She struck a pose in her yellow tank top and when we looked at the photos she said she was pleased with those. Relieved that we had finally come up with some portraits Yori was pleased with, I proceeded to find out a bit about her.
Yori is 19 and she was born in Sudan which borders Egypt and the Red Sea in North East Africa. She and her family came to Canada when she was 9. I had met her as she was heading home from the nearby Adult Learning Centre where she is completing high school. Her goal in life is to finish high school and college and train for a career as a pilot. She said “I know it will be a lot of work but that’s my goal.” Her interests outside school are art and photography. “Like you” she said with a smile.
Yori’s advice to her younger self was “Don’t let anyone tell you what to do – or who you are.” Her message to the project is “Stay strong and stay motivated.”
Once we exchanged contact information and were parting with a friendly handshake, I asked to take one more photo with my cell phone to demonstrate the location we used to make the portraits. I already knew that the challenges of the location were going to form a significant part of this story and I wanted to illustrate that. Yori looked at that photo on my phone and wanted to make sure I would send her that one as as well. I did.
This is my 832nd submission to The Human Family Group on Flickr.
You can view more street portraits and stories by visiting The Human Family.
As Roger had predicted, a small squad of Loreesi, about 8 soldiers and 2 noblemen, came to the oasis at about 2:00pm the following day. The Outlaws ambushed them. One nobleman was shot, and 2 soldiers were cut down before Gavin called a halt. The Loreesi huddled together, wondering what would happen to them. Gavin noted their terror, so he spoke to them.
"Don't worry, I'm not going to kill you. I'm holding you for ransom. It's not much, honestly. My men are hungry and we want food and money."
The remaining nobleman gulped.
"I have money and food, please may I send two of my soldiers back to my castle to get it?"
Gavin agreed and the two soldiers set off. They said they'd be back in about a week.
Gavin and his men brought them to their stronghold, back in the mountains, to wait out the week.
:-:-:-:-:-:-:-:-:-:-:-:-:-:-:-:-:-:-:-:-:-:-:-:-:-:-:-:-:
So this is my dio. It's also an entry to Mark's contest, but it's last minute so I'm not worried I'll win. : P
And yes, that is my real name on the border. Don't ask what the A stands for, because "wild anchovies wouldn't drag that out", as my friend says.
Before you ask, yes. She's a homeschooled Christian conservative and yes, at the speech group we're involved in, we're a little crazy sometimes.
Before you ask, no. She's not my girlfriend. I don't have one, don't plan to anytime soon.
Inspired by Mark of Falworth, and the palm trees were added just for him. ; )
-IronBricks
As predicted, the Pretendolino lives!
WB64 could perhaps be NC64, the set is on open ended lease to Greater Anglia as cover during the overhaul of the entire GA mk3 fleet. Presumably one of the DVT's is going as well.
25 October 2014 and 57302 leads the set with 37419 and 37682 on the rear through Glan Conwy station on the Conwy Valley branch. Silly train ain't gonna find Crown Point down there...
Google Trends Proves That Beards Aren't Dead (Or Even Dying).
Predicting the death of the beard has become an annual tradition for so-called style experts all over the internet.
Here are three tips to stay at the top of the beard game.
1. Don't be afraid to try a new style
One of the worst things we can do is get complacent with our style.
If your beard starts to look tired and dated, it makes you look like you have stopped caring, even stopped paying attention to the world around you.
Even a moderate style change can make a huge difference.
If you've been keeping a 3 or 4 inch beard, try keeping the same style, but bringing it down a couple of inches so that it more closely hugs your face.
Tighten up your look by keeping it short along the sides of the face, fade it into your hair at the sideburn, and make sure you're taking care of stray hairs by trimming regularly.
Had a goatee for years? Let your full beard grow out. Give it a bit of length and make sure you are grooming it daily. If you can't make it work, keep the full beard but try a stubble length.
If you're rocking a full beard, the possibilities are endless, but a more sleek, refined style like the Verdi is an easy first step into shaping your beard.
2. Pay attention to the little things
Attention to detail can make or break a man.
When people see that there are fly away hairs, a poorly trimmed (or not at all trimmed) neckline, or that you simply do not groom your beard at all, they're going to assume the worst.
If you can't even give your beard the attention it deserves, they'll think you don't pay attention in other areas of life, too.
Imagine the consequences when you're interviewing for a better job. Or trying to impress a potential mate.
You could lose out on a job or business opportunity, and even a relationship, because of your bad beard habits, so create a daily routine and make it a habit.
3. Condition daily with a balm or oil
Perhaps the most important method of your grooming routine, the foundation on which everything else rests, is the daily conditioning of your facial hair using a balm or an oil.
If you do nothing else, you will see significant results just from giving your beard a bit of moisturization.
Of course a balm helps control your beard and allows you to style it while keeping stray hairs in place, but your personal preference will dictate whether you use balm or oil.
The health, the shine, the overall cleanliness of your beard will be evident to all who look at it if you simply apply a bit of a natural moisturizing conditioner every morning.
Beards are not dead.
And that means more men than ever will be growing beards.
It's no longer enough to just grow a beard. You need a good beard to keep up with the competition. Get serious about your grooming habits and make sure that the more beards other men grow, the more yours stands out.
-------------------------
Candid street shot Toronto, Canada.
Taken at Knab Rock , Mumbles today with my phone after watching hail and rain showers pass furiously across the bay,
Come to Ireland. Say "It's going to rain".
Both umbrellas were confiscated shortly afterward by a banker, in a serious case of mixed idioms.
Vaccine rollout going well, weather not great and the masks making for photo opps that no one would have predicted.
Weather reports predict the so called "Beast From The East" is due to revisit the UK over the next few days, today the 16th of March 2018 I visited Collieston Bay, its the first time I have witnessed the impact unusual weather has had on the area, it really was exhilarating and offered great photo opportunities.
Collieston is a small former fishing village on the North Sea coast in Aberdeenshire, Scotland. The village lies just north of the Sands of Forvie Special Protection Area, between Cruden Bay and Newburgh.
The earliest recorded history of Collieston is of the arrival of St Ternan, a Columban monk on a mission to convert the local picts to Christianity. There is, however, evidence that people lived here during much earlier times.
Collieston was established as a fishing village by the 16th century, and it provides the first safe harbour in over fifteen miles of beachesand dunes stretching north from Aberdeen.
Fishing for herring, haddock, whiting and codflourished in the 17th century and 18th century and was the foundation of Collieston's economy. The village became known for 'Collieston Speldings', salted and sun-dried haddock and whiting, a popular delicacy throughout Britain. As drift netting developed during the mid 19th century, the fishing began to decline and the focus of the industry shifted to places like Peterhead because the harbour at Collieston was too small to safely accommodate the larger boats needed.
The numerous sea caves in the nearby cliffs, and small coves with shingle beaches provided ideal terrain for smugglers. In the late 18th century it was estimated by the Excise that up to 8000 gallons of foreign spirits were being illegally landed in the area every month. In 1798, the notorious village smuggler, Phillip Kennedy, was killed by a blow from an exciseman's cutlass. His grave and tombstone still stands in the village graveyard.
A ship from the Spanish Armada, the Santa Caterina, carrying arms for the Earl of Erroll is said to have sunk just off the rocky point of St Catherine's Dub in 1594. In retaliation for the Earl's involvement in the Catholic plot against him, James VI blew up the Earl's castle which stood on the cliffs, a mile north of Collieston. The Earl went on to rebuild Slains Castle, six miles further up the coast, in 1597.
Collieston is now mainly a commuter village serving Aberdeen, and is largely given over to tourists during the summer months.
This ESA/Webb Picture of the Month shows eight stunning examples of gravitational lensing. Gravitational lensing, which was first predicted by Einstein, occurs because massive objects like galaxies and clusters of galaxies dramatically warp the fabric of spacetime. When a massive foreground object lines up just so with a background galaxy, the light from the background galaxy bends as it navigates the warped spacetime on its way to our telescopes.
Depending on how perfect the alignment is, the light from the background galaxy can be bent into an arc, a circle (a phenomenon called an ‘Einstein ring’) or even split into multiple images.
Arcs and circles are prevalent in these gravitationally lensed galaxies, which were identified in data from COSMOS-Web, a 255-hour Treasury programme (#1727). COSMOS-Web aims to understand the formation of the most massive galaxies in the Universe, identify galaxies that were present when the first stars and galaxies reionised the Universe’s hydrogen gas, and study the relationship between the mass of a galaxy’s stars and the mass of its galactic halo across cosmic time.
Using these data, researchers carried out the COSMOS-Web Lens Survey, or COWLS, to search for gravitational lenses. The researchers inspected more than 42 000 galaxies by eye and picked out more than 400 promising lensing candidates. This Picture of the Month feature presents a collage of eight of the most spectacular lenses identified by the research team.
This collection of gravitational lenses spans an incredible range of cosmic history. The foreground galaxies give us a glimpse of galactic life when the Universe was 2.7 to 8.9 billion years old. The background galaxies, whose shapes appear visibly distorted, stretch back even further, with one source nicknamed ‘the COSMOS-Web Ring’ (top row, left of centre) letting us peek all the way back to when the Universe was barely more than a billion years old. Several rarities appear in this collection, including an unusual case in which the galaxy acting as the gravitational lens is a flattened disc galaxy rather than an elliptical galaxy (bottom row, second from left).
These images demonstrate Webb’s ability to uncover and reveal never-before-seen details in gravitationally lensed galaxies. Some of the lensed galaxies were previously discovered with the NASA/ESA Hubble Space Telescope and are now seen by Webb in an entirely new light. Others, including those that are especially red due to either dust or distance, were first spotted by Webb. These discoveries open a unique window into the early days of the Universe and enable the study of exquisite details within distant galaxies like individual star clusters and supernovae.
Individual images of the lenses are also available. From left-to-right then top-to-bottom: COSJ100013+023424, COSJ100024+015334, COSJ100018+022138, COSJ100024+021749, COSJ095914+021219, COSJ100025+015245, COSJ095921+020638, and COSJ095593+023319.
[Image Description: A collage of eight Webb images of gravitational lensing are shown. Each of the images show various distorted galaxies in the centre of each frame, including arcs and circular shapes.]
Credits: ESA/Webb, NASA & CSA, G. Gozaliasl, A. Koekemoer, M. Franco; CC BY 4.0
Midwest Tornadoes A well-predicted tornado outbreak swept across the Midwest on a Sunday afternoon, Nov. 17, 2013, wiping out the town of Washington, Illinois, just east of Peoria. These animation of GOES-EAST cloud top images on November 17 from 1300 to 2200 UTC/8 a.m. to 5 p.m. EST verify the hundreds of severe storms that were reported across Illinois and Indiana, but do not identify which ones had tornadoes beneath them.
Credit: NASA GOES Project/Dennis Chesters
NASA Goddard Space Flight Center enables NASA’s mission through four scientific endeavors: Earth Science, Heliophysics, Solar System Exploration, and Astrophysics. Goddard plays a leading role in NASA’s accomplishments by contributing compelling scientific knowledge to advance the Agency’s mission.
Follow us on Twitter
Like us on Facebook
Find us on Instagram
With Monday being the lowest predicted high temp for the next week, I decided to run out toward Crescent and Loveland to take some road and bridge photos to support a grant application I'm working on. I was really hoping for the CN because they've got the bridges that are suspect along the route, but I thought I was too late and that they'd departed before I got to CB. Luckily a freight was departing the UP yard at that time, so I chased it north and grabbed a shot I've not tried before on Joslin Ave., which parallels the UP from Benos to Crescent. He waved a bit too late for the shot, but it was nice to see a friendly conductor. The amount of waves I get without the kids these days is certainly less than it used to be. [Note that you'll need a ladder or a Subaroof to shoot here...]
(Please click to view on black)
Sometimes the weather forecasters predict a big storm to hit in the coming days, only to either be wrong or off a bit on the timing. But for the last 2-3 days, the National Weather Service kept saying a low pressure system would move into SW Arizona on Labor Day creating some intense storms and lots of rain.
Which is exactly what happened.
I had been planning on an all-day, noon-to-midnight stormchasing event for Labor Day and was pumped when Monday morning nothing in the forecast had changed. My buddy Ken met me at my house around 12:30 and we flew west of Phoenix and then south to Gila Bend.
If we had driven to Yuma, we might have seem some really nasty stuff, but that's a long haul. So we hung out around the northern parts of Gila Bend, shooting storms in the farmlands and irrigation areas. Caught a few night photographs that will be shared at a later time.
But this lightning shot came almost 30 miles south of Gila Bend on Highway 85. I literally ran across a low area and up a hill to setup for this shot, which ended up being the highest spot around. The lightning wasn't close, but it's definitely not the wisest thing in the world to do.
I didn't have much of a choice. I could see a gorgeous sunset going on and some stormy clouds with strong downdrafts of rain. It took awhile, many shots, but I finally got a decent strike before the beautiful color of the sunset disappeared on me.
(canon 5d mark ii, tamron 17-35mm 2.8, 17mm, iso 250, f/10, 6sec)
As i predicted in my Magical player shot, Rogers Federer took his revenge against Novak Djokovic yesterday by beating him (7-6,7-6, 6-4)
By winning this game, Federer achieved:
1) His 4 th straight US open (2004-2005-2006 and 2007). It's a new record.
2) 12 th Grand Slam titles (the second after Sampras who has won 14 Grand Slem titles
3) 2,4 millions dollars for just the US open title (poor of him)
To see my tennis set
Have a great week !
Did you know that the "Marseille tarot" is associated with the city? Why do you ask? It was brought by Mary Magdalene, the hidden wife of Jesus. She came to Provence, not Marseille. Aren't you wondering why the decks contain 78 cards if only 22 are used? And has anyone ever told you that the Tarot was never designed to predict the future? This includes the Tarot's history and the rich symbolic significance of the Magdalene heresy that is embedded into its images. This hidden heresy relates to the recognition of Mary Magdalene as the wife of Jesus Christ. This sheds light on the need for the balance of the Divine Feminine and Divine Masculine in our World today.
The gypsy clairvoyants recovered the Tarot for its particularly effective system for understanding all the unconscious mechanisms, for better orienting oneself towards the right choices, and ultimately for healing.Mary Magdalene (Mary of Magdala), the woman with the jars in Christian symbolism, could well in this case be represented in the star chart. But their hypotheses stopped there. No one had ever imagined that the Tarot itself represented the teaching and life of Mary Magdalene in its entirety, let alone that the Tarot had been created by Mary Magdalene herself in the first century.It changes the dating of the Tarot from the 14th century to the 1st century AD with Mary Magdalene, the Tarot de Marseille thus becoming the ancestor of all Western tarot cards, i.e. "the Tarot".
Historians and experts say that the Tarot originated in Italy during the Renaissance, towards the end of the 14th century and the beginning of the 15th. On the other hand, nobody thought that the Tarot de Marseille itself came from Marseille.Mary Magdalene is the Saint who was the first witness to Christ's resurrection. In other words, she sees the Resurrection. Now, in the Tarot, if you look again at the Judgement and the World side by side, you will see that the Saint in the World card is looking in the direction of the light blue Christ who is rising from his tomb. So here we have a major Tarot code which explains that the naked Saint in the World card is the one who witnesses Christ's resurrection.
fr.camoin.com/tarot/Tarot-Marie-Madeleine-Magdala.html
This tradition begins with the MAT, the traveller who sets off in search of the Grail, but also the people of the MAT, the gypsies. The tradition was reborn with esotericism around 1880. That's when Wirth arrived at Guaita's. How did they send this to Waite? He's still waiting for the piece of the jigsaw to be put together into a clearer system. We're sticking to the stuff available in the web stock.
Oswald Wirth is known for his occult and esoteric work on the Tarot de Marseille. He produced his own version of the 22 Major Arcana cards, and also worked on representing the Minor Arcana with the help of Gérard Encausse, known as Papus, who also studied the Tarot for occult and esoteric purposes, and Arthur Edward Waite, who also produced his own tarot with the popular success we all know. The links between Wirth and Waite are still a secret, but the agility at the heart of esoteric houses and the porosity that may have existed before the 1914 war. Today it's remains like a mirage and that's hard to imagine an other mind. So I've tried to compile some information about these great men, these great initiates, because today everything has been reduced and simplified.
The Rider-Waite-Smith Tarot is a deck of tarot cards traditionally used for divination and spiritual practice. It was designed by English illustrator Arthur Edward Waite and American designer Pamela Colman Smith, and first published in 1909. It uses the codes and symbols of the Tarot de Stanislas de la Guaita illustrated by Oswald Wirth. Oswald Wirth was Stanislas de Guaita's secretary, and in collaboration with him drew a Tarot, which has since been republished as the Wirth Tarot. It is also known for its occult symbols and its references to the Hermetic tradition and the Kabbalah. The Rider-Waite-Smith Tarot is one of the most popular and widely used tarot decks in the world. It has inspired many interpreters, authors and practitioners of divination, as well as artists and writers.
Wrapping it All Up…
To summarize, the Nine of Cups is a card of actualization, accomplishment and indulgence. It can also mean the reverse depending on its orientation. It holds significance in many areas of your life, from success and riches, to love and loss. Spiritually, it speaks to a feeling of fulfillment, and materially, it calls to plenty. That was everything you might need to know about the Nine of Cups and the meanings associated with drawing the card. We feel the need to clarify that despite the orientation you may draw the card in, not to fret or become too complacent. The tarot cards do not control or enforce their readings in any aspect of your life. They tell a possible story, based on divination and your own vibrations that attract their energies. Because of this, you can play into the reading or shatter expectations completely.There is not much to say about the booklet because there are only 5 translated pages per language. A brief summary of Oswald Wirth's life precedes the presentation of the 22 cards of the Major Arcana. Each card has an explanation in 3 or 4 sentences. The publisher guarantees that the meanings are as faithful as possible to Wirth's vision.
en.tarotquest.fr/review-en-007-golden-wirth-tarot.html
Remember that even drawing the card upright does not mean you can sit back and good things will come to you. The card calls you to action to go after what you want, appreciate what you have, and indulge in the rewards. Conversely, drawing the Nine of Cups in reverse calls you to exercise caution, reflection, and self-discovery. This is because whether it’s the stars, a roll of the dice, or the draw of the card doesn’t matter. The Universe guides us, not shackles us to our fate, and ultimately you alone are in control of your life.
Wirth is best known as the author of Le Tarot des imagiers du Moyen Âge (1927), translated and published in English as The Tarot of the Magicians. Joseph Paul Oswald Wirth (5 August 1860, Brienz, Canton of Bern – 9 March 1943) was a Swiss occultist, artist and author. He studied esotericism and symbolism with Stanislas de Guaita and in 1889 he created, under the guidance of de Guaita, a cartomantic Tarot consisting only of the twenty-two Major Arcana. Known as "Les 22 Arcanes du Tarot Kabbalistique", it followed the designs of the Tarot de Marseille closely but introduced several alterations, incorporating extant occult symbolism into the cards. The Wirth/de Guaita deck is significant in the history of the tarot for being the first in a long line of occult, cartomantic, and initiatory decks.
The occult in life: Stanislas de Guaita - memories of his secretary Oswald Wirth
They recruited Gérard Encausse to help rebuild the tradition of alchemists. Encausse, who went by the pseudonym “Papus”, was a Spanish-born French physician and occultist who had written books on magic, Cabalah and the Tarot. From the end of the 19th century until his death, Oswald Wirth (1860-1943) exercised a veritable moral magisterium over French alchemy. Through his works and the magazine Le Symbolisme, which he founded and edited, he made a major contribution to restoring to alchemy its spiritualist and symbolic dimension, largely abandoned during the 19th century in favor of political battles. His personality and aura inspired Jules Romain to create the character of Alchemist Lengnau in Recherche d'une Eglise (volume 7 of Les Hommes de bonne Volonté). Initiated in January 1884 in a Châlons-sur-Marne laboratory during his military service, he left the alchemists of France to join the Great Work shortly after settling in Paris. Secretary to Stanislas de Guaïta (1861-1897), a writer and poet whom his friend Maurice Barrès described as "the renovator of occultism", he owed it to him, by his own admission, to "write legibly". Although he denounced what he called "low occultism", Wirth (who was a magnetizer) nourished part of his symbolic reflection with Hermetic contributions.
Oswald Wirth's symbolic tarot is one of the few tarot cards to reveal the key to the knowledge of the ancient initiates, secretly conveyed for millennia.
The theosophical reductions (what can be learned from the experience we live) and the tetrads (the experience itself, its origin and its possible development), enable everyone to interpret the messages of the 78 beautifully illustrated cards with accuracy and precision. The historical tarot deck, created in the Marseilles style, is based upon the original designs by famous Swiss kabbalist and occultist Oswald Wirth. The 22 Major Arcana first appeared in 1889 in a hand-colored limit edition deck. The 22 Major cards have French titles and the Hebrew letters attributed to each card by Eliphas Levi, and popularized by Oswald Wirth. This authorized full 78-card deck is printed with vivid colors on gold background. The 56 Minor Arcana cards present the four traditional suits of Swords, Batons, Cups and Coins. The pack includes a booklet of commentary by Stuart R.
www.usgamesinc.com/oswald-wirth-tarot.html
Stanislas de Guaita (6 April 1861, Tarquimpol, Moselle – 19 December 1897, Tarquimpol) was a French poet based in Paris, an expert on esotericism and European mysticism, and an active member of the Rosicrucian Order. He was very celebrated and successful in his time. He had many disputes with other people who were involved with occultism and magic. Occultism and magic were part of his novels. De Guaita came from a noble Italian family who had relocated to France, and as such his title was 'Marquis', or Marquess. He was born in the castle of Alteville in the commune of Tarquimpol, Moselle, and went to school at the lyceum in Nancy, where he studied chemistry, metaphysics and Cabala. As a young man, he moved to Paris, and his luxurious apartment became a meeting place for poets, artists, and writers who were interested in esotericism and mysticism. In the 1880s, Guaita published two collections of poetry The Dark Muse (1883) and The Mystic Rose (1885), which became popular. De Guaita was influenced by the writings of l'Abbé Alphonse-Louis Constant, alias Eliphas Lévi, a prominent French occultist who was initiated in London to rosicrucianism by Edward Bulwer-Lytton in 1854. Eliphas Lévi was also initiated as a Freemason on 14 March 1861 in the Grand Orient de France Lodge La Rose du Parfait Silence at the Orient of Paris. De Guaita became further interested in occultism after reading a novel by Joséphin Péladan which was interwoven with Rosicrucian and occult themes. In Paris, de Guaita and Péladan became acquainted, and in 1884, the two decided to try to rebuild the Rosicrucian Brotherhood. They recruited Gérard Encausse to help rebuild the brotherhood. Encausse, who went by the pseudonym “Papus”, was a Spanish-born French physician and occultist who had written books on magic, Cabalah and the Tarot.
In 1888, De Guaita founded the Ordre kabbalistique de la Rose-Croix, or the Kabbalistic Order of the Rose-Cross. Rosicrucianism is an esoteric movement which first began with the publication of the three Rosicrucian Manifestos in the early 17th century. Guaita's Rosicrucian Order provided training in the Cabala, an esoteric form of Jewish and Christian mysticism, which attempts to reveal hidden mystical insights in the Bible and divine nature. The order also conducted examinations and provided university degrees on Cabala topics. Guaita had a large private library of books on metaphysical issues, magic, and the "hidden sciences." He was nicknamed the "Prince of the Rosicrucians" by his contemporaries for his broad learning on Rosicrucian issues. Papus, Peladan, and Antoine de La Rochefoucauld were prominent members. Maurice Barrès was a close friend of De Guaita.
In the late 1880s, the Abbé Boullan, a defrocked Catholic Priest and the head of a schismatic branch called the “Church of the Carmel” led a “magical war” against de Guaita. French-Belgian novelist Joris K. Huysmans, a supporter of Boullan, portrayed De Guaita as a Satanic sorcerer in the novel La Bas. Another of Boullan’s supporters, the writer Jules Bois, challenged De Guaita to a pistol duel. De Guaita agreed and took part in the duel, but as both men missed, no one was hurt.
By the 1890s, De Guaita's, Papus' and Péladan’s collaboration became increasingly strained by disagreements over strategy and doctrines. Guaita and Papus lost the support of Péladan, who left to start a competing order. De Guaita died in 1897 at the age of 36.
His original drawing of an inverted pentagram with a goat's head appeared in La Clef de la Magie Noire (The Key to Black Magic), published the year he died. It later became conflated with Baphomet, or the Sabbatic Goat. In 1888, De Guaita founded the Ordre kabbalistique de la Rose-Croix, or the Kabbalistic Order of the Rose-Cross. Rosicrucianism is an esoteric movement which first began with the publication of the three Rosicrucian Manifestos in the early 17th century. Guaita's Rosicrucian Order provided training in the Cabala, an esoteric form of Jewish and Christian mysticism, which attempts to reveal hidden mystical insights in the Bible and divine nature. The order also conducted examinations and provided university degrees on Cabala topics. Guaita had a large private library of books on metaphysical issues, magic, and the "hidden sciences." He was nicknamed the "Prince of the Rosicrucians" by his contemporaries for his broad learning on Rosicrucian issues. Papus, Peladan, and Antoine de La Rochefoucauld were prominent members. Maurice Barrès was a close friend of De Guaita. In the late 1880s, the Abbé Boullan, a defrocked Catholic Priest and the head of a schismatic branch called the “Church of the Carmel” led a “magical war” against de Guaita. French-Belgian novelist Joris K. Huysmans, a supporter of Boullan, portrayed De Guaita as a Satanic sorcerer in the novel La Bas. Another of Boullan’s supporters, the writer Jules Bois, challenged De Guaita to a pistol duel. De Guaita agreed and took part in the duel, but as both men missed, no one was hurt. By the 1890s, De Guaita's, Papus' and Péladan’s collaboration became increasingly strained by disagreements over strategy and doctrines. Guaita and Papus lost the support of Péladan, who left to start a competing order. De Guaita died in 1897 at the age of 36. His original drawing of an inverted pentagram with a goat's head appeared in La Clef de la Magie Noire (The Key to Black Magic), published the year he died. It later became conflated with Baphomet, or the Sabbatic Goat.
en.wikipedia.org/wiki/Stanislas_de_Guaita
Lévi and Wirth interests also included Freemasonry and Astrology. He wrote many books in French regarding Freemasonry, most importantly a set of three volumes explaining Freemasonry's first three degrees. On January 28, 1884, Wirth was initiated in the regular Scottish Rite Masonic Lodge La Bienfaisance Châlonnaise affiliated to the Grand Orient of France. In 1889, he joined the Scottish Rite Travail et les Vrais Amis Fidèles where he became Grand Master . In 1898, the latter lodge was admitted to the Grand Lodge of France.
Works[edit]
Le Livre de Thot comprenant les 22 arcanes du Tarot (1889).
L'Imposition des mains et la médecine philosophale (1897), Paris.
La Franc-maçonnerie rendue intelligible à ses adeptes, sa philosophie, son objet, sa méthode, ses moyens, three volumes:
Vol. I: Le livre de l'Apprenti : manuel d'instruction rédigé à l'usage des FF. du 1er degré (1893, 2nd revised edition 1908), Paris.
Vol. II: Le livre du Compagnon : manuel d'instruction rédigé à l'usage des FF. du 2° degré (1912), Paris.
Vol. III: Le livre du Maître : manuel d'instruction rédigé à l'usage des FF. du 3° degré (1922), Paris.
Le Symbolisme hermétique dans ses rapports avec l'alchimie et la franc-maçonnerie (1910), Paris.
Les Signes du zodiaque, leur symbolisme initiatique (1921), Paris.
Le Serpent vert (1922) (translation and analysis of Das Märchen by Goethe), Paris.
L'Idéal initiatique (1924), Paris.
Le Tarot des imagiers du Moyen Âge (1927), Paris.
Introduction à l’étude du tarot (1931), Paris.
Les Mystères de l'art royal - Rituel de l'adepte (1932), Paris.
Stanislas de Guaïta, souvenirs de son secrétaire (1935), Paris.
Le Symbolisme astrologique : planètes, signes du zodiaque, maisons de l'horoscope, aspects, étoiles fixes (1938), Paris.
Qui est régulier ? Le pur maçonnisme sous le Régime des Grandes Loges inauguré en 1717 (1938), Paris.
en.wikipedia.org/wiki/Oswald_Wirth
Interpretation of this Cards
Ace of Cups's Meaning
The Ace of Cups signifies the beginning of period of strong emotional health for you. Expect copious joy, happiness, and love to surround you during this time. Existing personal relationships may strengthen, meaningful new ones are likely to form. If marriage is in your future, you are likely to lay the foundations for it during this time.The Ace of Cups represents overall satisfaction throughout all different areas of your life. It predicts success and abundance through use of good intuition and creativity. New relationships or possibly a birth or pregnancy could be associated with these positive outlooks.
www.trustedtarot.com/cards/ace-of-cups/
The Wheel of Fortune's Meaning
Symbolic of life's cycles, the Wheel of Fortune speaks to good beginnings. Most likely, you will find the events foretold to be positive, but, being aspects of luck, they may also be beyond your control and influence. Tend those things you can control with care, and learn not to agonize over the ones you cannot.
www.trustedtarot.com/cards/wheel-of-fortune/
The Star's Meaning
The Star's presence signifies a period of respite and renewal for you. This renewal may be spiritual, physical, or both. It is a particularly positive sign if you or someone close is recovering from illness or injury. It is a light in the darkness, illuminating your future and your past.
www.trustedtarot.com/cards/the-star/
Eight of Wands's Meaning
Prepare yourself for an abrupt increase in the pace of your life. Things are about to get very busy. They good news is that any projects you begin will progress quickly, you will experience few delays, and the conclusion is likely to be successful. This card is also good news for relationships, although it raises the possibility of needing to travel for relationships. All things considered, this is a good card to find in your spread, as long as you are willing to buckle down and get to work.
www.trustedtarot.com/cards/eight-of-wands/
Drawing on Success: Nine of Cups Tarot Card Meaning
What else is there to glean from the card? It represents the fulfillment of a goal or some deep, unfulfilled desire. But tarot cards are tricky business. Their meaning is usually tied to the context of a situation, and in fact many diviners will read more than one card during a fortune telling. The meaning of Nine of Cups then, can change depending on its adjacent cards.
Its meaning can also change depending on where you are in life. What you’re struggling with, or where you’ve been or are going also changes the card’s meaning. Our tarot aficionados reading this article will also acutely point out that tarot cards have two different meanings, depending on the orientation that the card is facing when drawn. The Nine of Cups upright meaning is different from the Nine of Cups reversed meaning!
We’ll go over as many of these as we can in this article, to prepare you for everything you’d need to expect after drawing this card. Maybe you’re a tarot card enthusiast brushing up on knowledge or maybe you’ve recently had or thought about getting a divination. Perhaps you’re simply curious and want to find out more. Whatever the case, we hope you find this article educational, enlightening, and most importantly, fun! Without further ado, everything you need to know about the Nine of Cups:
Upright: Everything You Need to Know(That We can Think of!)
After a long trial in your life, the Nine of Cups represents a positive, fruitful conclusion. The nine cups are sometimes interpreted to mean different ups and downs, or different challenges you’ve faced before now. Now is important, because the Nine of Cups encourages you to ‘drink up.’ That you should happily partake in the success you have worked and endured for. The tarot card is a wake-up call that you have entered a positive chapter in your life, and should enjoy it. The Nine of Cups can also refer to something in the future in a different context. If you are yearning for something, and draw the Nine of Cups, there’s a good chance it will come true! Indeed, this tarot card is sometimes referred to as the wish card. Because of its association with fulfillment and plenty, the tarot card also has positive meanings in health, love, career and finances. We’ll go over each below: Career-wise, the Nine of Cups focuses more on the confident, successful man more than the cups of blessings themselves. You will find yourself taking in the admiration of your peers and workmates. It’s likely that tasks you found challenging or difficult before are becoming easier or even menial to accomplish. This is the time to look towards possible advancement in your position. Maybe move to a different job that holds better opportunities. This is also a prime time to ask for a raise. Move confidently. Though arrogance is a fool’s errand, don’t shy away from the rewards waiting for you. Your superiors are likely more receptive towards such moves in light of your increase in skill. Most importantly, at the end of the journey symbolized by the nine cups, you’ve likely earned this.ust as in your career, financially the Nine of Cups signifies blessings and comfort. This is the time to relax, to treat yourself a little. From tiny things like the raise you’re likely to score to a bonus on performance here and there, things will add up. While thrift is a virtue in itself, it can’t hurt to celebrate your success a little. You’ll likely need it.Remember that the good times won’t last forever. Fear of what is to come often takes away from the now. Remember that you’ve earned the success and subsequent rewards that come to you. In fact, what we’re going over next has a lot to do with the opposite of everything you’ve read so far. The reversed meaning of this card in particular is a sign of the bad times to come.To summarize, the Nine of Cups is a card of actualization, accomplishment and indulgence. It can also mean the reverse depending on its orientation. It holds significance in many areas of your life, from success and riches, to love and loss. Spiritually, it speaks to a feeling of fulfillment, and materially, it calls to plenty.
That was everything you might need to know about the Nine of Cups and the meanings associated with drawing the card. We feel the need to clarify that despite the orientation you may draw the card in, not to fret or become too complacent. The tarot cards do not control or enforce their readings in any aspect of your life. They tell a possible story, based on divination and your own vibrations that attract their energies. Because of this, you can play into the reading or shatter expectations completely.
Remember that even drawing the card upright does not mean you can sit back and good things will come to you. The card calls you to action to go after what you want, appreciate what you have, and indulge in the rewards. Conversely, drawing the Nine of Cups in reverse calls you to exercise caution, reflection, and self-discovery. This is because whether it’s the stars, a roll of the dice, or the draw of the card doesn’t matter. The Universe guides us, not shackles us to our fate, and ultimately you alone are in control of your life.
trusted-astrology.com/nine-of-cups-meaning/
Originally from German-speaking Switzerland, Oswald Wirth (1860-1943) arrived in Paris at the age of twenty. Here he became acquainted with various enthusiasts of the occult sciences, in particular the members of the Société Magnétique de France, among whom he soon became known for his abilities as a "curative magnetiser". After a short stay in London, in 1884 he joined the Grand Orient de France, an event that kindled his interest in Masonic symbolism.Early in 1887 he met Stanislas de Guaita, with whom he formed a deep and indissoluble friendship. The Marquis introduced the young man to the study of the Cabala and the Tarot, and after the necessary period of apprenticeship welcomed him as a member of the OKCR, the Kabbalistic Order of the Rosicrucians. Having noticed his drawing skills, he suggested that Wirth design a new deck, with the aim of restoring the cards to their "hieroglyphic purity", as Eliphas Lévi had wished in his day.En partant de la base de deux jeux, le Tarot de Marseille (un Tarot de Besançon précisément) et un jeu italien, Wirth fit une élaboration importante, surtout en ce qui concernait (selon sa vision) la correction des erreurs présentes, la juste attribution des couleurs et les détails singuliers des figures. Ainsi virent le jour, après à peine un an, Les XXII Arcanes du Tarot kabbalistique, restitués à leur pureté hiéroglyphique sous les indications de Stanislas de Guaita (Paris, 1889).Early in 1887 he met Stanislas de Guaita, with whom he formed a deep and indissoluble friendship. The Marquis introduced the young man to the study of the Cabala and the Tarot, and after the necessary period of apprenticeship welcomed him as a member of the OKCR, the Kabbalistic Order of the Rosicrucians. Having noticed his drawing skills, he suggested that Wirth design a new deck, with the aim of restoring the cards to their "hieroglyphic purity", as Eliphas Lévi had wished in his day.The reference to Guaita was accurate because, although the Marquis left no writings on the Tarot, it is correct to think that Wirth's Arcana were an expression of his teachings. Wirth himself acknowledged that he had been introduced to the mysteries of esotericism by his spiritual father."Guaita, knowing me to be a draughtsman, advised me from our first meeting in the spring of 1887, to restore the 22 Arcana of the Tarot to their hieroglyphic purity, and immediately documented this by entrusting me with two tarots, one French and the other Italian, as well as the Dogme et Rituel de la Haute Magie, the capital work of Eliphas Levi, in which the Tarot is the subject of copious commentaries. This was the starting point for the present work, whose spiritual authorship is attributable to Stanislas de Guaita. Having submitted to him a first Tarot redesigned according to the rough decks compared, this learned occultist offered me his criticisms, which were taken into account when the Kabbalistic Tarot was published in 1889. (...) With the help of Stanislas de Guaita, I set to work to acquire the science of symbolism that would allow me to reconstitute the Tarot. (...) As soon as one succeeds in making the symbols speak, they surpass all speeches in eloquence, for they enable one to rediscover the lost Word, that is to say the eternal living thought of which they are the enigmatic expression. Decipher the hieroglyphs of the profound silent wisdom common to thinkers of all ages and religions, of myths and poetic fictions, and you will come up with concordant notions relating to the problems that have always preoccupied the human mind". (Oswald Wirth, The 22 Arcana of the Kabbalistic Tarot restored to their hieroglyphic purity under the guidance of Stanislas de Guaita). Each major arcana is marked with a Hebrew letter, according to the scheme devised by Eliphas Levi. According to many, Wirth had the merit of knowing how to accept and summarise the thought and principles of the most important Masonic initiatory currents. He used them to interpret the secrets of the Great Work, devoting himself to the study of alchemy, the Cabala and the Tarot. For Wirth, symbolism was a universal value, and he tried to bring the teachings of the various esoteric schools down to a common matrix through the use of a common symbology, derived directly from the archetypal concepts of Masonic thought. He wrote texts on the Tarot in which he defined the art of divination as a kind of priesthood, and numerous texts on Freemasonry, in which he tried to make the institution comprehensible to laymen and adepts alike in a simple yet transcendent way:
"Such a definition is realistic if we consider that the person exercising divination must feel himself to be a 'mediator', a 'means', an 'intermediary' and an 'instrument' of such capacity. A priest is: the moment he performs a ritual, the power of that ritual captivates and involves him to the point where it almost cancels out his very personality."
www.franck-durand.fr/lhistoire-oswald-wirth-tarot-du-moye...
1929 Knapp-Hall
Published in Los Angeles using the chromo lithography process, this deck of seventy-eight cards is the oldest tarot deck inspired by Wirth's that we have been able to find. It was created by the artist J. Augustus Knapp (1853-1938) in collaboration with Manly P. Hall, director of the Philosophical Research Society in Los Angeles. In addition to the many features of the Wirth tarot on each illustration, the yellow cartouche is as it appeared on Oswald Wirth's first tarot: with the title in capitals (and the World with the double numbering 21 and 22). The fifty-six minor arcana are freely created. The backs of the cards also feature the word TARO (without the T). This deck was republished in 1985 by the USGS under the name Knapp-Hall Tarot.
www.tarot-artisanal.fr/enquete-des-tarots-dits-de-oswald-...
Weather.com predicted cloudy skies on Sunday evening. Good thing I ignored their forecast and decided to shoot anyway. Turns out, the skies were clear enough for a pretty decent sunset, captured from East Boston in the LoPresti Park area. Admittedly, the composition is a bit busy, but I had little else to work with, so here you go.
SkyFire predicted a decent chance of a colorful sunset on this day before the remnants of Hurricane Rosa arrived, so I decided to check out the Burnham badlands in NW New Mexico. Not as showy or well known as other hoodoo lands in the Bisti and Ah-Shi-Sle-Pah, there was still plenty to see and photograph. Best of all, my pal Colorado Plateau photographer extraordinaire Cecil Whitt & I had the place all to ourselves.
Different forms of fluctuations of the terrestrial gravity field are observed by gravity experiments. For example, atmospheric pressure fluctuations generate a gravity-noise foreground in measurements with super-conducting gravimeters. Gravity changes caused by high-magnitude earthquakes have been detected with the satellite gravity experiment GRACE, and we expect high-frequency terrestrial gravity fluctuations produced by ambient seismic fields to limit the sensitivity of ground-based gravitational-wave (GW) detectors. Accordingly, terrestrial gravity fluctuations are considered noise and signal depending on the experiment. Here, we will focus on ground-based gravimetry. This field is rapidly progressing through the development of GW detectors. The technology is pushed to its current limits in the advanced generation of the LIGO and Virgo detectors, targeting gravity strain sensitivities better than 10−23 Hz−1/2 above a few tens of a Hz. Alternative designs for GW detectors evolving from traditional gravity gradiometers such as torsion bars, atom interferometers, and superconducting gradiometers are currently being developed to extend the detection band to frequencies below 1 Hz. The goal of this article is to provide the analytical framework to describe terrestrial gravity perturbations in these experiments. Models of terrestrial gravity perturbations related to seismic fields, atmospheric disturbances, and vibrating, rotating or moving objects, are derived and analyzed. The models are then used to evaluate passive and active gravity noise mitigation strategies in GW detectors, or alternatively, to describe their potential use in geophysics. The article reviews the current state of the field, and also presents new analyses especially with respect to the impact of seismic scattering on gravity perturbations, active gravity noise cancellation, and time-domain models of gravity perturbations from atmospheric and seismic point sources. Our understanding of terrestrial gravity fluctuations will have great impact on the future development of GW detectors and high-precision gravimetry in general, and many open questions need to be answered still as emphasized in this article.
Keywords: Terrestrial gravity, Newtonian noise, Wiener filter, Mitigation
Go to:
Introduction
In the coming years, we will see a transition in the field of high-precision gravimetry from observations of slow lasting changes of the gravity field to the experimental study of fast gravity fluctuations. The latter will be realized by the advanced generation of the US-based LIGO [1] and Europe-based Virgo [7] gravitational-wave (GW) detectors. Their goal is to directly observe for the first time GWs that are produced by astrophysical sources such as inspiraling and merging neutron-star or black-hole binaries. Feasibility of the laser-interferometric detector concept has been demonstrated successfully with the first generation of detectors, which, in addition to the initial LIGO and Virgo detectors, also includes the GEO600 [119] and TAMA300 [161] detectors, and several prototypes around the world. The impact of these projects onto the field is two-fold. First of all, the direct detection of GWs will be a milestone in science opening a new window to our universe, and marking the beginning of a new era in observational astronomy. Second, several groups around the world have already started to adapt the technology to novel interferometer concepts [60, 155], with potential applications not only in GW science, but also geophysics. The basic measurement scheme is always the same: the relative displacement of test masses is monitored by using ultra-stable lasers. Progress in this field is strongly dependent on how well the motion of the test masses can be shielded from the environment. Test masses are placed in vacuum and are either freely falling (e.g., atom clouds [137]), or suspended and seismically isolated (e.g., high-quality glass or crystal mirrors as used in all of the detectors listed above). The best seismic isolations realized so far are effective above a few Hz, which limits the frequency range of detectable gravity fluctuations. Nonetheless, low-frequency concepts are continuously improving, and it is conceivable that future detectors will be sufficiently sensitive to detect GWs well below a Hz [88].
Terrestrial gravity perturbations were identified as a potential noise source already in the first concept laid out for a laser-interferometric GW detector [171]. Today, this form of noise is known as “terrestrial gravitational noise”, “Newtonian noise”, or “gravity-gradient noise”. It has never been observed in GW detectors, but it is predicted to limit the sensitivity of the advanced GW detectors at low frequencies. The most important source of gravity noise comes from fluctuating seismic fields [151]. Gravity perturbations from atmospheric disturbances such as pressure and temperature fluctuations can become significant at lower frequencies [51]. Anthropogenic sources of gravity perturbations are easier to avoid, but could also be relevant at lower frequencies [163]. Today, we only have one example of a direct observation of gravity fluctuations, i.e., from pressure fluctuations of the atmosphere in high-precision gravimeters [128]. Therefore, almost our entire understanding of gravity fluctuations is based on models. Nonetheless, potential sensitivity limits of future large-scale GW detectors need to be identified and characterized well in advance, and so there is a need to continuously improve our understanding of terrestrial gravity noise. Based on our current understanding, the preferred option is to construct future GW detectors underground to avoid the most dominant Newtonian-noise contributions. This choice was made for the next-generation Japanese GW detector KAGRA, which is currently being constructed underground at the Kamioka site [17], and also as part of a design study for the Einstein Telescope in Europe [140, 139]. While the benefit from underground construction with respect to gravity noise is expected to be substantial in GW detectors sensitive above a few Hz [27], it can be argued that it is less effective at lower frequencies [88].
Alternative mitigation strategies includes coherent noise cancellation [42]. The idea is to monitor the sources of gravity perturbations using auxiliary sensors such as microphones and seismometers, and to use their data to generate a coherent prediction of gravity noise. This technique is successfully applied in gravimeters to reduce the foreground of atmospheric gravity noise using collocated pressure sensors [128]. It is also noteworthy that the models of the atmospheric gravity noise are consistent with observations. This should give us some confidence at least that coherent Newtonian-noise cancellation can also be achieved in GW detectors. It is evident though that a model-based prediction of the performance of coherent noise cancellation schemes is prone to systematic errors as long as the properties of the sources are not fully understood. Ongoing experiments at the Sanford Underground Research Facility with the goal to characterize seismic fields in three dimensions are expected to deliver first data from an underground seismometer array in 2015 (see [89] for results from an initial stage of the experiment). While most people would argue that constructing GW detectors underground is always advantageous, it is still necessary to estimate how much is gained and whether the science case strongly profits from it. This is a complicated problem that needs to be answered as part of a site selection process.
More recently, high-precision gravity strainmeters have been considered as monitors of geophysical signals [83]. Analytical models have been calculated, which allow us to predict gravity transients from seismic sources such as earthquakes. It was suggested to implement gravity strainmeters in existing earthquake-early warning systems to increase warning times. It is also conceivable that an alternative method to estimate source parameters using gravity signals will improve our understanding of seismic sources. Potential applications must still be investigated in greater detail, but the study already demonstrates that the idea to use GW technology to realize new geophysical sensors seems feasible. As explained in [49], gravitational forces start to dominate the dynamics of seismic phenomena below about 1 mHz (which coincides approximately with a similar transition in atmospheric dynamics where gravity waves start to dominate over other forms of oscillations [164]). Seismic isolation would be ineffective below 1 mHz since the gravitational acceleration of a test mass produced by seismic displacement becomes comparable to the seismic acceleration itself. Therefore, we claim that 10 mHz is about the lowest frequency at which ground-based gravity strainmeters will ever be able to detect GWs, and consequently, modelling terrestrial gravity perturbations in these detectors can focus on frequencies above 10 mHz.
This article is divided into six main sections. Section 2 serves as an introduction to gravity measurements focussing on the response mechanisms and basic properties of gravity sensors. Section 3 describes models of gravity perturbations from ambient seismic fields. The results can be used to estimate noise spectra at the surface and underground. A subsection is devoted to the problem of noise estimation in low-frequency GW detectors, which differs from high-frequency estimates mostly in that gravity perturbations are strongly correlated between different test masses. In the low-frequency regime, the gravity noise is best described as gravity-gradient noise. Section 4 is devoted to time domain models of transient gravity perturbations from seismic point sources. The formalism is applied to point forces and shear dislocations. The latter allows us to estimate gravity perturbations from earthquakes. Atmospheric models of gravity perturbations are presented in Section 5. This includes gravity perturbations from atmospheric temperature fields, infrasound fields, shock waves, and acoustic noise from turbulence. The solution for shock waves is calculated in time domain using the methods of Section 4. A theoretical framework to calculate gravity perturbations from objects is given in Section 6. Since many different types of objects can be potential sources of gravity perturbations, the discussion focusses on the development of a general method instead of summarizing all of the calculations that have been done in the past. Finally, Section 7 discusses possible passive and active noise mitigation strategies. Due to the complexity of the problem, most of the section is devoted to active noise cancellation providing the required analysis tools and showing limitations of this technique. Site selection is the main topic under passive mitigation, and is discussed in the context of reducing environmental noise and criteria relevant to active noise cancellation. Each of these sections ends with a summary and a discussion of open problems. While this article is meant to be a review of the current state of the field, it also presents new analyses especially with respect to the impact of seismic scattering on gravity perturbations (Sections 3.3.2 and 3.3.3), active gravity noise cancellation (Section 7.1.3), and timedomain models of gravity perturbations from atmospheric and seismic point sources (Sections 4.1, 4.5, and 5.3).
Even though evident to experts, it is worth emphasizing that all calculations carried out in this article have a common starting point, namely Newton’s universal law of gravitation. It states that the attractive gravitational force equation M1 between two point masses m1, m2 is given by
equation M21
where G = 6.672 × 10−11 N m2/kg2 is the gravitational constant. Eq. (1) gives rise to many complex phenomena on Earth such as inner-core oscillations [156], atmospheric gravity waves [157], ocean waves [94, 177], and co-seismic gravity changes [122]. Due to its importance, we will honor the eponym by referring to gravity noise as Newtonian noise in the following. It is thereby clarified that the gravity noise models considered in this article are non-relativistic, and propagation effects of gravity changes are neglected. While there could be interesting scenarios where this approximation is not fully justified (e.g., whenever a gravity perturbation can be sensed by several sensors and differences in arrival times can be resolved), it certainly holds in any of the problems discussed in this article. We now invite the reader to enjoy the rest of the article, and hope that it proves to be useful.
Go to:
Gravity Measurements
In this section, we describe the relevant mechanisms by which a gravity sensor can couple to gravity perturbations, and give an overview of the most widely used measurement schemes: the (relative) gravimeter [53, 181], the gravity gradiometer [125], and the gravity strainmeter. The last category includes the large-scale GW detectors Virgo [6], LIGO [91], GEO600 [119], KAGRA [17], and a new generation of torsion-bar antennas currently under development [13]. Also atom interferometers can potentially be used as gravity strainmeters in the future [62]. Strictly speaking, none of the sensors only responds to a single field quantity (such as changes in gravity acceleration or gravity strain), but there is always a dominant response mechanism in each case, which justifies to give the sensor a specific name. A clear distinction between gravity gradiometers and gravity strainmeters has never been made to our knowledge. Therefore the sections on these two measurement principles will introduce a definition, and it is by no means the only possible one. Later on in this article, we almost exclusively discuss gravity models relevant to gravity strainmeters since the focus lies on gravity fluctuations above 10 mHz. Today, the sensitivity near 10 mHz of gravimeters towards gravity fluctuations is still competitive to or exceeds the sensitivity of gravity strainmeters, but this is likely going to change in the future so that we can expect strainmeters to become the technology of choice for gravity observations above 10 mHz [88]. The following sections provide further details on this statement. Space-borne gravity experiments such as GRACE [167] will not be included in this overview. The measurement principle of GRACE is similar to that of gravity strainmeters, but only very slow changes of Earth gravity field can be observed, and for this reason it is beyond the scope of this article.
The different response mechanisms to terrestrial gravity perturbations are summarized in Section 2.1. While we will identify the tidal forces acting on the test masses as dominant coupling mechanism, other couplings may well be relevant depending on the experiment. The Shapiro time delay will be discussed as the only relativistic effect. Higher-order relativistic effects are neglected. All other coupling mechanisms can be calculated using Newtonian theory including tidal forces, coupling in static non-uniform gravity fields, and coupling through ground displacement induced by gravity fluctuations. In Sections 2.2 to 2.4, the different measurement schemes are explained including a brief summary of the sensitivity limitations (choosing one of a few possible experimental realizations in each case). As mentioned before, we will mostly develop gravity models relevant to gravity strainmeters in the remainder of the article. Therefore, the detailed discussion of alternative gravimetry concepts mostly serves to highlight important differences between these concepts, and to develop a deeper understanding of the instruments and their role in gravity measurements.
Gravity response mechanisms
Gravity acceleration and tidal forces We will start with the simplest mechanism of all, the acceleration of a test mass in the gravity field. Instruments that measure the acceleration are called gravimeters. A test mass inside a gravimeter can be freely falling such as atom clouds [181] or, as suggested as possible future development, even macroscopic objects [72]. Typically though, test masses are supported mechanically or magnetically constraining motion in some of its degrees of freedom. A test mass suspended from strings responds to changes in the horizontal gravity acceleration. A test mass attached at the end of a cantilever with horizontal equilibrium position responds to changes in vertical gravity acceleration. The support fulfills two purposes. First, it counteracts the static gravitational force in a way that the test mass can respond to changes in the gravity field along a chosen degree of freedom. Second, it isolates the test mass from vibrations. Response to signals and isolation performance depend on frequency. If the support is modelled as a linear, harmonic oscillator, then the test mass response to gravity changes extends over all frequencies, but the response is strongly suppressed below the oscillators resonance frequency. The response function between the gravity perturbation δg(ω) and induced test mass acceleration δa(ω) assumes the form
equation M32
where we have introduced a viscous damping parameter γ, and ω0 is the resonance frequency. Well below resonance, the response is proportional to ω2, while it is constant well above resonance. Above resonance, the supported test mass responds like a freely falling mass, at least with respect to “soft” directions of the support. The test-mass response to vibrations δα(ω) of the support is given by
equation M43
This applies for example to horizontal vibrations of the suspension points of strings that hold a test mass, or to vertical vibrations of the clamps of a horizontal cantilever with attached test mass. Well above resonance, vibrations are suppressed by ω−2, while no vibration isolation is provided below resonance. The situation is somewhat more complicated in realistic models of the support especially due to internal modes of the mechanical system (see for example [76]), or due to coupling of degrees of freedom [121]. Large mechanical support structures can feature internal resonances at relatively low frequencies, which can interfere to some extent with the desired performance of the mechanical support [173]. While Eqs. (2) and (3) summarize the properties of isolation and response relevant for this paper, details of the readout method can fundamentally impact an instrument’s response to gravity fluctuations and its susceptibility to seismic noise, as explained in Sections 2.2 to 2.4.
Next, we discuss the response to tidal forces. In Newtonian theory, tidal forces cause a relative acceleration δg12(ω) between two freely falling test masses according to
equation M54
where equation M6 is the Fourier amplitude of the gravity potential. The last equation holds if the distance r12 between the test masses is sufficiently small, which also depends on the frequency. The term equation M7 is called gravity-gradient tensor. In Newtonian approximation, the second time integral of this tensor corresponds to gravity strain equation M8, which is discussed in more detail in Section 2.4. Its trace needs to vanish in empty space since the gravity potential fulfills the Poisson equation. Tidal forces produce the dominant signals in gravity gradiometers and gravity strainmeters, which measure the differential acceleration or associated relative displacement between two test masses (see Sections 2.3 and 2.4). If the test masses used for a tidal measurement are supported, then typically the supports are designed to be as similar as possible, so that the response in Eq. (2) holds for both test masses approximately with the same parameter values for the resonance frequencies (and to a lesser extent also for the damping). For the purpose of response calibration, it is less important to know the parameter values exactly if the signal is meant to be observed well above the resonance frequency where the response is approximately equal to 1 independent of the resonance frequency and damping (here, “well above” resonance also depends on the damping parameter, and in realistic models, the signal frequency also needs to be “well below” internal resonances of the mechanical support).
Shapiro time delay Another possible gravity response is through the Shapiro time delay [19]. This effect is not universally present in all gravity sensors, and depends on the readout mechanism. Today, the best sensitivities are achieved by reflecting laser beams from test masses in interferometric configurations. If the test mass is displaced by gravity fluctuations, then it imprints a phase shift onto the reflected laser, which can be observed in laser interferometers, or using phasemeters. We will give further details on this in Section 2.4. In Newtonian gravity, the acceleration of test masses is the only predicted response to gravity fluctuations. However, from general relativity we know that gravity also affects the propagation of light. The leading-order term is the Shapiro time delay, which produces a phase shift of the laser beam with respect to a laser propagating in flat space. It can be calculated from the weak-field spacetime metric (see chapter 18 in [124]):
equation M95
Here, c is the speed of light, ds is the so-called line element of a path in spacetime, and equation M10. Additionally, for this metric to hold, motion of particles in the source of the gravity potential responsible for changes of the gravity potential need to be much slower than the speed of light, and also stresses inside the source must be much smaller than its mass energy density. All conditions are fulfilled in the case of Earth gravity field. Light follows null geodesics with ds2 = 0. For the spacetime metric in Eq. (5), we can immediately write
equation M116
As we will find out, this equation can directly be used to calculate the time delay as an integral along a straight line in terms of the coordinates equation M12, but this is not immediately clear since light bends in a gravity field. So one may wonder if integration along the proper light path instead of a straight line yields additional significant corrections. The so-called geodesic equation must be used to calculate the path. It is a set of four differential equations, one for each coordinate t, equation M13 in terms of a parameter λ. The weak-field geodesic equation is obtained from the metric in Eq. (5):
equation M147
where we have made use of Eq. (6) and the slow-motion condition equation M15. The coordinates equation M16 are to be understood as functions of λ. Since the deviation of a straight path is due to a weak gravity potential, we can solve these equations by perturbation theory introducing expansions equation M17 and t = t(0) +t(1) + …. The superscript indicates the order in ψ/c2. The unperturbed path has the simple parametrization
equation M188
We have chosen integration constants such that unperturbed time t(0) and parameter λ can be used interchangeably (apart from a shift by t0). Inserting these expressions into the right-hand side of Eq. (7), we obtain
equation M199
As we can see, up to linear order in equation M20, the deviation equation M21 is in orthogonal direction to the unperturbed path equation M22, which means that the deviation can be neglected in the calculation of the time delay. After some transformations, it is possible to derive Eq. (6) from Eq. (9), and this time we find explicitly that the right-hand-side of the equation only depends on the unperturbed coordinates1. In other words, we can integrate the time delay along a straight line as defined in Eq. (8), and so the total phase integrated over a travel distance L is given by
equation M2310
In static gravity fields, the phase shift doubles if the light is sent back since not only the direction of integration changes, but also the sign of the expression substituted for dt/dλ.
Gravity induced ground motion As we will learn in Section 3, seismic fields produce gravity perturbations either through density fluctuations of the ground, or by displacing interfaces between two materials of different density. It is also well-known in seismology that seismic fields can be affected significantly by self-gravity. Self-gravity means that the gravity perturbation produced by a seismic field acts back on the seismic field. The effect is most significant at low frequency where gravity induced acceleration competes against acceleration from elastic forces. In seismology, low-frequency seismic fields are best described in terms of Earth’s normal modes [55]. Normal modes exist as toroidal modes and spheroidal modes. Spheroidal modes are influenced by self-gravity, toroidal modes are not. For example, predictions of frequencies and shapes of spheroidal modes based on Earth models such as PREM (Preliminary Reference Earth Model) [68] are inaccurate if self-gravity effects are excluded. What this practically means is that in addition to displacement amplitudes, gravity becomes a dynamical variable in the elastodynamic equations that determine the normal-mode properties. Therefore, seismic displacement and gravity perturbation cannot be separated in normal-mode formalism (although self-gravity can be neglected in calculations of spheroidal modes at sufficiently high frequency).
In certain situations, it is necessary or at least more intuitive to separate gravity from seismic fields. An exotic example is Earth’s response to GWs [67, 49, 47, 30, 48]. Another example is the seismic response to gravity perturbations produced by strong seismic events at large distance to the source as described in Section 4. It is more challenging to analyze this scenario using normal-mode formalism. The sum over all normal modes excited by the seismic event (each of which describing a global displacement field) must lead to destructive interference of seismic displacement at large distances (where seismic waves have not yet arrived), but not of the gravity amplitudes since gravity is immediately perturbed everywhere. It can be easier to first calculate the gravity perturbation from the seismic perturbation, and then to calculate the response of the seismic field to the gravity perturbation at larger distance. This method will be adopted in this section. Gravity fields will be represented as arbitrary force or tidal fields (detailed models are presented in later sections), and we simply calculate the response of the seismic field. Normal-mode formalism can be avoided only at sufficiently high frequencies where the curvature of Earth does not significantly influence the response (i.e., well above 10 mHz). In this section, we will model the ground as homogeneous half space, but also more complex geologies can in principle be assumed.
Gravity can be introduced in two ways into the elastodynamic equations, as a conservative force −∇ψ [146, 169], or as tidal strain The latter method was described first by Dyson to calculate Earth’s response to GWs [67]. The approach also works for Newtonian gravity, with the difference that the tidal field produced by a GW is necessarily a quadrupole field with only two degrees of freedom (polarizations), while tidal fields produced by terrestrial sources are less constrained. Certainly, GWs can only be fully described in the framework of general relativity, which means that their representation as a Newtonian tidal field cannot be used to explain all possible observations [124]. Nonetheless, important here is that Dyson’s method can be extended to Newtonian tidal fields. Without gravity, the elastodynamic equations for small seismic displacement can be written as
equation M2411
where equation M25 is the seismic displacement field, and equation M26 is the stress tensor [9]. In the absence of other forces, the stress is determined by the seismic field. In the case of a homogeneous and isotropic medium, the stress tensor for small seismic displacement can be written as
equation M2712
The quantity equation M28 is known as seismic strain tensor, and λ, μ are the Lamé constants (see Section 3.1). Its trace is equal to the divergence of the displacement field. Dyson introduced the tidal field from first principles using Lagrangian mechanics, but we can follow a simpler approach. Eq. (12) means that a stress field builds up in response to a seismic strain field, and the divergence of the stress field acts as a force producing seismic displacement. The same happens in response to a tidal field, which we represent as gravity strain equation M29. A strain field changes the distance between two freely falling test masses separated by equation M30 by equation M312. For sufficiently small distances L, the strain field can be substituted by the second time integral of the gravity-gradient tensor equation M32. If the masses are not freely falling, then the strain field acts as an additional force. The corresponding contribution to the material’s stress tensor can be written
equation M3313
Since we assume that the gravity field is produced by a distant source, the local contribution to gravity perturbations is neglected, which means that the gravity potential obeys the Laplace equation, equation M34. Calculating the divergence of the stress tensor according to Eq. (11), we find that the gravity term vanishes! This means that a homogeneous and isotropic medium does not respond to gravity strain fields. However, we have to be more careful here. Our goal is to calculate the response of a half-space to gravity strain. Even if the half-space is homogeneous, the Lamé constants change discontinuously across the surface. Hence, at the surface, the divergence of the stress tensor reads
equation M3514
In other words, tidal fields produce a force onto an elastic medium via gradients in the shear modulus (second Lamé constant). The gradient of the shear modulus can be written in terms of a Dirac delta function, equation M36, for a flat surface at z = 0 with unit normal vector equation M37. The response to gravity strain fields is obtained applying the boundary condition of vanishing surface traction, equation M38:
equation M3915
Once the seismic strain field is calculated, it can be used to obtain the seismic stress, which determines the displacement field equation M40 according to Eq. (11). In this way, one can for example calculate that a seismometer or gravimeter can observe GWs by monitoring surface displacement as was first calculated by Dyson [67].
Coupling in non-uniform, static gravity fields If the gravity field is static, but non-uniform, then displacement equation M41 of the test mass in this field due to a non-gravitational fluctuating force is associated with a changing gravity acceleration according to
equation M4216
We introduce a characteristic length λ, over which gravity acceleration varies significantly. Hence, we can rewrite the last equation in terms of the associated test-mass displacement ζ
equation M4317
where we have neglected directional dependence and numerical factors. The acceleration change from motion in static, inhomogeneous fields is generally more significant at low frequencies. Let us consider the specific case of a suspended test mass. It responds to fluctuations in horizontal gravity acceleration. The test mass follows the motion of the suspension point in vertical direction (i.e., no seismic isolation), while seismic noise in horizontal direction is suppressed according to Eq. (3). Accordingly, it is possible that the unsuppressed vertical (z-axis) seismic noise ξz(t) coupling into the horizontal (x-axis) motion of the test mass through the term ∂xgz = ∂zgx dominates over the gravity response term in Eq. (2). Due to additional coupling mechanisms between vertical and horizontal motion in real seismic-isolation systems, test masses especially in GW detectors are also isolated in vertical direction, but without achieving the same noise suppression as in horizontal direction. For example, the requirements on vertical test-mass displacement for Advanced LIGO are a factor 1000 less stringent than on the horizontal displacement [22]. Requirements can be set on the vertical isolation by estimating the coupling of vertical motion into horizontal motion, which needs to take the gravity-gradient coupling of Eq. (16) into account. Although, because of the frequency dependence, gravity-gradient effects are more significant in low-frequency detectors, such as the space-borne GW detector LISA [154].
Next, we calculate an estimate of gravity gradients in the vicinity of test masses in large-scale GW detectors, and see if the gravity-gradient coupling matters compared to mechanical vertical-to-horizontal coupling.
One contribution to gravity gradients will come from the vacuum chamber surrounding the test mass. We approximate the shape of the chamber as a hollow cylinder with open ends (open ends just to simplify the calculation). In our calculation, the test mass can be offset from the cylinder axis and be located at any distance to the cylinder ends (we refer to this coordinate as height). The gravity field can be expressed in terms of elliptic integrals, but the explicit solution is not of concern here. Instead, let us take a look at the results in Figure Figure1.1. Gravity gradients ∂zgx vanish if the test mass is located on the symmetry axis or at height L/2. There are also two additional ∂zgx = 0 contour lines starting at the symmetry axis at heights ∼ 0.24 and ∼0.76. Let us assume that the test mass is at height 0.3L, a distance 0.05L from the cylinder axis, the total mass of the cylinder is M = 5000 kg, and the cylinder height is L = 4 m. In this case, the gravity-gradient induced vertical-to-horizontal coupling factor at 20 Hz is
equation M4418
This means that gravity-gradient induced coupling is extremely weak, and lies well below estimates of mechanical coupling (of order 0.001 in Advanced LIGO3). Even though the vacuum chamber was modelled with a very simple shape, and additional asymmetries in the mass distribution around the test mass may increase gravity gradients, it still seems very unlikely that the coupling would be significant. As mentioned before, one certainly needs to pay more attention when calculating the coupling at lower frequencies. The best procedure is of course to have a 3D model of the near test-mass infrastructure available and to use it for a precise calculation of the gravity-gradient field.
An external file that holds a picture, illustration, etc.
Object name is 41114_2016_3_Fig1.jpg
Figure 1
Gravity gradients inside hollow cylinder. The total height of the cylinder is L, and M is its total mass. The radius of the cylinder is 0.3L. The axes correspond to the distance of the test mass from the symmetry axis of the cylinder, and its height above one of the cylinders ends. The plot on the right is simply a zoom of the left plot into the intermediate heights.
Gravimeters
Gravimeters are instruments that measure the displacement of a test mass with respect to a non-inertial reference rigidly connected to the ground. The test mass is typically supported mechanically or magnetically (atom-interferometric gravimeters are an exception), which means that the test-mass response to gravity is altered with respect to a freely falling test mass. We will use Eq. (2) as a simplified response model. There are various possibilities to measure the displacement of a test mass. The most widespread displacement sensors are based on capacitive readout, as for example used in superconducting gravimeters (see Figure Figure22 and [96]). Sensitive displacement measurements are in principle also possible with optical readout systems; a method that is (necessarily) implemented in atom-interferometric gravimeters [137], and prototype seismometers [34] (we will explain the distinction between seismometers and gravimeters below). As will become clear in Section 2.4, optical readout is better suited for displacement measurements over long baselines, as required for the most sensitive gravity strain measurements, while the capacitive readout should be designed with the smallest possible distance between the test mass and the non-inertial reference [104].
An external file that holds a picture, illustration, etc.
Object name is 41114_2016_3_Fig2.jpg
Figure 2
Sketch of a levitated sphere serving as test mass in a superconducting gravimeter. Dashed lines indicate magnetic field lines. Coils are used for levitation and precise positioning of the sphere. Image reproduced with permission from [96]; copyright by Elsevier.
Let us take a closer look at the basic measurement scheme of a superconducting gravimeter shown in Figure Figure2.2. The central part is formed by a spherical superconducting shell that is levitated by superconducting coils. Superconductivity provides stability of the measurement, and also avoids some forms of noise (see [96] for details). In this gravimeter design, the lower coil is responsible mostly to balance the mean gravitational force acting on the sphere, while the upper coil modifies the magnetic gradient such that a certain “spring constant” of the magnetic levitation is realized. In other words, the current in the upper coil determines the resonance frequency in Eq. (2).
Capacitor plates are distributed around the sphere. Whenever a force acts on the sphere, the small signal produced in the capacitive readout is used to immediately cancel this force by a feedback coil. In this way, the sphere is kept at a constant location with respect to the external frame. This illustrates a common concept in all gravimeters. The displacement sensors can only respond to relative displacement between a test mass and a surrounding structure. If small gravity fluctuations are to be measured, then it is not sufficient to realize low-noise readout systems, but also vibrations of the surrounding structure forming the reference frame must be as small as possible. In general, as we will further explore in the coming sections, gravity fluctuations are increasingly dominant with decreasing frequency. At about 1 mHz, gravity acceleration associated with fluctuating seismic fields become comparable to seismic acceleration, and also atmospheric gravity noise starts to be significant [53]. At higher frequencies, seismic acceleration is much stronger than typical gravity fluctuations, which means that the gravimeter effectively operates as a seismometer. In summary, at sufficiently low frequencies, the gravimeter senses gravity accelerations of the test mass with respect to a relatively quiet reference, while at higher frequencies, the gravimeter senses seismic accelerations of the reference with respect to a test mass subject to relatively small gravity fluctuations. In superconducting gravimeters, the third important contribution to the response is caused by vertical motion ξ(t) of a levitated sphere against a static gravity gradient (see Section 2.1.4). As explained above, feedback control suppresses relative motion between sphere and gravimeter frame, which causes the sphere to move as if attached to the frame or ground. In the presence of a static gravity gradient ∂zgz, the motion of the sphere against this gradient leads to a change in gravity, which alters the feedback force (and therefore the recorded signal). The full contribution from gravitational, δa(t), and seismic, equation M45, accelerations can therefore be written
equation M4619
It is easy to verify, using Eqs. (2) and (3), that the relative amplitude of gravity and seismic fluctuations from the first two terms is independent of the test-mass support. Therefore, vertical seismic displacement of the reference frame must be considered fundamental noise of gravimeters and can only be avoided by choosing a quiet measurement site. Obviously, Eq. (19) is based on a simplified support model. One of the important design goals of the mechanical support is to minimize additional noise due to non-linearities and cross-coupling. As is explained further in Section 2.3, it is also not possible to suppress seismic noise in gravimeters by subtracting the disturbance using data from a collocated seismometer. Doing so inevitably turns the gravimeter into a gravity gradiometer.
Gravimeters target signals that typically lie well below 1 mHz. Mechanical or magnetic supports of test masses have resonance frequencies at best slightly below 10 mHz along horizontal directions, and typically above 0.1 Hz in the vertical direction [23, 174]4. Well below resonance frequency, the response function can be approximated as equation M47. At first, it may look as if the gravimeter should not be sensitive to very low-frequency fluctuations since the response becomes very weak. However, the strength of gravity fluctuations also strongly increases with decreasing frequency, which compensates the small response. It is clear though that if the resonance frequency was sufficiently high, then the response would become so weak that the gravity signal would not stand out above other instrumental noise anymore. The test-mass support would be too stiff. The sensitivity of the gravimeter depends on the resonance frequency of the support and the intrinsic instrumental noise. With respect to seismic noise, the stiffness of the support has no influence as explained before (the test mass can also fall freely as in atom interferometers).
For superconducting gravimeters of the Global Geodynamics Project (GGP) [52], the median spectra are shown in Figure Figure3.3. Between 0.1 mHz and 1 mHz, atmospheric gravity perturbations typically dominate, while instrumental noise is the largest contribution between 1 mHz and 5 mHz [96]. The smallest signal amplitudes that have been measured by integrating long-duration signals is about 10−12 m/s2. A detailed study of noise in superconducting gravimeters over a larger frequency range can be found in [145]. Note that in some cases, it is not fit to categorize seismic and gravity fluctuations as noise and signal. For example, Earth’s spherical normal modes coherently excite seismic and gravity fluctuations, and the individual contributions in Eq. (19) have to be understood only to accurately translate data into normal-mode amplitudes [55].
An external file that holds a picture, illustration, etc.
Object name is 41114_2016_3_Fig3.jpg
Figure 3
Median spectra of superconducting gravimeters of the GGP. Image reproduced with permission from [48]; copyright by APS.
Gravity gradiometers
It is not the purpose of this section to give a complete overview of the different gradiometer designs. Gradiometers find many practical applications, for example in navigation and resource exploration, often with the goal to measure static or slowly changing gravity gradients, which do not concern us here. For example, we will not discuss rotating gradiometers, and instead focus on gradiometers consisting of stationary test masses. While the former are ideally suited to measure static or slowly changing gravity gradients with high precision especially under noisy conditions, the latter design has advantages when measuring weak tidal fluctuations. In the following, we only refer to the stationary design. A gravity gradiometer measures the relative acceleration between two test masses each responding to fluctuations of the gravity field [102, 125]. The test masses have to be located close to each other so that the approximation in Eq. (4) holds. The proximity of the test masses is used here as the defining property of gradiometers. They are therefore a special type of gravity strainmeter (see Section 2.4), which denotes any type of instrument that measures relative gravitational acceleration (including the even more general concept of measuring space-time strain).
Gravity gradiometers can be realized in two versions. First, one can read out the position of two test masses with respect to the same rigid, non-inertial reference. The two channels, each of which can be considered a gravimeter, are subsequently subtracted. This scheme is for example realized in dual-sphere designs of superconducting gravity gradiometers [90] or in atom-interferometric gravity gradiometers [159].
It is schematically shown in Figure Figure4.4. Let us first consider the dual-sphere design of a superconducting gradiometer. If the reference is perfectly stiff, and if we assume as before that there are no cross-couplings between degrees of freedom and the response is linear, then the subtraction of the two gravity channels cancels all of the seismic noise, leaving only the instrumental noise and the differential gravity signal given by the second line of Eq. (4). Even in real setups, the reduction of seismic noise can be many orders of magnitude since the two spheres are close to each other, and the two readouts pick up (almost) the same seismic noise [125]. This does not mean though that gradiometers are necessarily more sensitive instruments to monitor gravity fields. A large part of the gravity signal (the common-mode part) is subtracted together with the seismic noise, and the challenge is now passed from finding a seismically quiet site to developing an instrument with lowest possible intrinsic noise.
An external file that holds a picture, illustration, etc.
Object name is 41114_2016_3_Fig4.jpg
Figure 4
Basic scheme of a gravity gradiometer for measurements along the vertical direction. Two test masses are supported by horizontal cantilevers (superconducting magnets, …). Acceleration of both test masses is measured against the same non-inertial reference frame, which is connected to the ground. Each measurement constitutes one gravimeter. Subtraction of the two channels yields a gravity gradiometer.
The atom-interferometric gradiometer differs in some important details from the superconducting gradiometer. The test masses are realized by ultracold atom clouds, which are (nearly) freely falling provided that magnetic shielding of the atoms is sufficient, and interaction between atoms can be neglected. Interactions of a pair of atom clouds with a laser beam constitute the basic gravity gradiometer scheme. Even though the test masses are freely falling, the readout is not generally immune to seismic noise [80, 18]. The laser beam interacting with the atom clouds originates from a source subject to seismic disturbances, and interacts with optics that require seismic isolation. Schemes have been proposed that could lead to a large reduction of seismic noise [178, 77], but their effectiveness has not been tested in experiments yet. Since the differential position (or tidal) measurement is performed using a laser beam, the natural application of atom-interferometer technology is as gravity strainmeter (as explained before, laser beams are favorable for differential position measurements over long baselines). Nonetheless, the technology is currently insufficiently developed to realize large-baseline experiments, and we can therefore focus on its application in gradiometry. Let us take a closer look at the response of atom-interferometric gradiometers to seismic noise. In atom-interferometric detectors (excluding the new schemes proposed in [178, 77]), one can show that seismic acceleration δα(ω) of the optics or laser source limits the sensitivity of a tidal measurement according to
equation M4820
where L is the separation of the two atom clouds, and is the speed of light. It should be emphasized that the seismic noise remains, even if all optics and the laser source are all linked to the same infinitely stiff frame. In addition to this noise term, other coupling mechanisms may play a role, which can however be suppressed by engineering efforts. The noise-reduction factor ωL/c needs to be compared with the common-mode suppression of seismic noise in superconducting gravity gradiometers, which depends on the stiffness of the instrument frame, and on contamination from cross coupling of degrees-of-freedom. While the seismic noise in Eq. (20) is a fundamental noise contribution in (conventional) atom-interferometric gradiometers, the noise suppression in superconducting gradiometers depends more strongly on the engineering effort (at least, we venture to claim that common-mode suppression achieved in current instrument designs is well below what is fundamentally possible).
To conclude this section, we discuss in more detail the connection between gravity gradiometers and seismically (actively or passively) isolated gravimeters. As we have explained in Section 2.2, the sensitivity limitation of gravimeters by seismic noise is independent of the mechanical support of the test mass (assuming an ideal, linear support). The main purpose of the mechanical support is to maximize the response of the test mass to gravity fluctuations, and thereby increase the signal with respect to instrumental noise other than seismic noise. Here we will explain that even a seismic isolation of the gravimeter cannot overcome this noise limitation, at least not without fundamentally changing its response to gravity fluctuations. Let us first consider the case of a passively seismically isolated gravimeter. For example, we can imagine that the gravimeter is suspended from the tip of a strong horizontal cantilever. The system can be modelled as two oscillators in a chain, with a light test mass m supported by a heavy mass M representing the gravimeter (reference) frame, which is itself supported from a point rigidly connected to Earth. The two supports are modelled as harmonic oscillators. As before, we neglect cross coupling between degrees of freedom. Linearizing the response of the gravimeter frame and test mass for small accelerations, and further neglecting terms proportional to m/M, one finds the gravimeter response to gravity fluctuations:
equation M4921
Here, ω1, γ1 are the resonance frequency and damping of the gravimeter support, while ω2, γ2 are the resonance frequency and damping of the test-mass support. The response and isolation functions R(·), S(·) are defined in Eqs. (2) and (3). Remember that Eq. (21) is obtained as a differential measurement of test-mass acceleration versus acceleration of the reference frame. Therefore, δg1(ω) denotes the gravity fluctuation at the center-of-mass of the gravimeter frame, and δg2(ω) at the test mass. An infinitely stiff gravimeter suspension, ω1 → ∞, yields R(ω; ω1, γ1) = 0, and the response turns into the form of the non-isolated gravimeter. The seismic isolation is determined by
equation M5022
We can summarize the last two equations as follows. At frequencies well above ω1, the seismically isolated gravimeter responds like a gravity gradiometer, and seismic noise is strongly suppressed. The deviation from the pure gradiometer response ∼ δg2(ω) − δg1(ω) is determined by the same function S(ω; ω1, γ1) that describes the seismic isolation. In other words, if the gravity gradient was negligible, then we ended up with the conventional gravimeter response, with signals suppressed by the seismic isolation function. Well below ω1, the seismically isolated gravimeter responds like a conventional gravimeter without seismic-noise reduction. If the centers of the masses m (test mass) and M (reference frame) coincide, and therefore δg1(ω) = δg2(ω), then the response is again like a conventional gravimeter, but this time suppressed by the isolation function S(ω; ω1, γ1).
Let us compare the passively isolated gravimeter with an actively isolated gravimeter. In active isolation, the idea is to place the gravimeter on a stiff platform whose orientation can be controlled by actuators. Without actuation, the platform simply follows local surface motion. There are two ways to realize an active isolation. One way is to place a seismometer next to the platform onto the ground, and use its data to subtract ground motion from the platform. The actuators cancel the seismic forces. This scheme is called feed-forward noise cancellation. Feed-forward cancellation of gravity noise is discussed at length in Section 7.1, which provides details on its implementation and limitations. The second possibility is to place the seismometer together with the gravimeter onto the platform, and to suppress seismic noise in a feedback configuration [4, 2]. In the following, we discuss the feed-forward technique as an example since it is easier to analyze (for example, feedback control can be unstable [4]). As before, we focus on gravity and seismic fluctuations. The seismometer’s intrinsic noise plays an important role in active isolation limiting its performance, but we are only interested in the modification of the gravimeter’s response. Since there is no fundamental difference in how a seismometer and a gravimeter respond to seismic and gravity fluctuations, we know from Section 2.2 that the seismometer output is proportional to δg1(ω) − δα(ω), i.e., using a single test mass for acceleration measurements, seismic and gravity perturbations contribute in the same way. A transfer function needs to be multiplied to the acceleration signals, which accounts for the mechanical support and possibly also electronic circuits involved in the seismometer readout. To cancel the seismic noise of the platform that carries the gravimeter, the effect of all transfer functions needs to be reversed by a matched feed-forward filter. The output of the filter is then equal to δg1(ω) − δα(ω) and is added to the motion of the platform using actuators cancelling the seismic noise and adding the seismometer’s gravity signal. In this case, the seismometer’s gravity signal takes the place of the seismic noise in Eq. (3). The complete gravity response of the actively isolated gravimeter then reads
equation M5123
The response is identical to a gravity gradiometer, where ω2, γ2 are the resonance frequency and damping of the gravimeter’s test-mass support. In reality, instrumental noise of the seismometer will limit the isolation performance and introduce additional noise into Eq. (23). Nonetheless, Eqs. (21) and (23) show that any form of seismic isolation turns a gravimeter into a gravity gradiometer at frequencies where seismic isolation is effective. For the passive seismic isolation, this means that the gravimeter responds like a gradiometer at frequencies well above the resonance frequency ω1 of the gravimeter support, while it behaves like a conventional gravimeter below ω1. From these results it is clear that the design of seismic isolations and the gravity response can in general not be treated independently. As we will see in Section 2.4 though, tidal measurements can profit strongly from seismic isolation especially when common-mode suppression of seismic noise like in gradiometers is insufficient or completely absent.
Gravity strainmeters
Gravity strain is an unusual concept in gravimetry that stems from our modern understanding of gravity in the framework of general relativity. From an observational point of view, it is not much different from elastic strain. Fluctuating gravity strain causes a change in distance between two freely falling test masses, while seismic or elastic strain causes a change in distance between two test masses bolted to an elastic medium. It should be emphasized though that we cannot always use this analogy to understand observations of gravity strain [106]. Fundamentally, gravity strain corresponds to a perturbation of the metric that determines the geometrical properties of spacetime [124]. We will briefly discuss GWs, before returning to a Newtonian description of gravity strain.
Gravitational waves are weak perturbations of spacetime propagating at the speed of light. Freely falling test masses change their distance in the field of a GW. When the length of the GW is much larger than the separation between the test masses, it is possible to interpret this change as if caused by a Newtonian force. We call this the long-wavelength regime. Since we are interested in the low-frequency response of gravity strainmeters throughout this article (i.e., frequencies well below 100 Hz), this condition is always fulfilled for Earth-bound experiments. The effect of a gravity-strain field equation M52 on a pair of test masses can then be represented as an equivalent Newtonian tidal field
equation M5324
Here, equation M54 is the relative acceleration between two freely falling test masses, L is the distance between them, and equation M55 is the unit vector pointing from one to the other test mass, and equation M56 its transpose. As can be seen, the gravity-strain field is represented by a 3 × 3 tensor. It contains the space-components of a 4-dimensional metric perturbation of spacetime, and determines all properties of GWs5. Note that the strain amplitude h in Eq. (24) needs to be multiplied by 2 to obtain the corresponding amplitude of the metric perturbation (e.g., the GW amplitude). Throughout this article, we define gravity strain as h = ΔL/L, while the effect of a GW with amplitude aGW on the separation of two test mass is determined by aGW = 2ΔL/L.
The strain field of a GW takes the form of a quadrupole oscillation with two possible polarizations commonly denoted × (cross)-polarization and +(plus)-polarization. The arrows in Figure Figure55 indicate the lines of the equivalent tidal field of Eq. (24).
An external file that holds a picture, illustration, etc.
Object name is 41114_2016_3_Fig5.jpg
Figure 5
Polarizations of a gravitational wave.
Consequently, to (directly) observe GWs, one can follow two possible schemes: (1) the conventional method, which is a measurement of the relative displacement of suspended test masses typically carried out along two perpendicular baselines (arms); and (2) measurement of the relative rotation between two suspended bars. Figure Figure66 illustrates the two cases. In either case, the response of a gravity strainmeter is obtained by projecting the gravity strain tensor onto a combination of two unit vectors, equation M57 and equation M58, that characterize the orientation of the detector, such as the directions of two bars in a rotational gravity strain meter, or of two arms of a conventional gravity strain meter. This requires us to define two different gravity strain projections. The projection for the rotational strain measurement is given by
equation M5925
where the subscript × indicates that the detector responds to the ×-polarization assuming that the x, y-axes (see Figure Figure5)5) are oriented along two perpendicular bars. The vectors equation M60 and equation M61 are rotated counter-clockwise by 90° with respect to equation M62 and equation M63. In the case of perpendicular bars equation M64 and equation M65. The corresponding projection for the conventional gravity strain meter reads
equation M6626
The subscript + indicates that the detector responds to the +-polarization provided that the x, y-axes are oriented along two perpendicular baselines (arms) of the detector. The two schemes are shown in Figure Figure6.6. The most sensitive GW detectors are based on the conventional method, and distance between test masses is measured by means of laser interferometry. The LIGO and Virgo detectors have achieved strain sensitivities of better than 10−22 Hz−1/2 between about 50 Hz and 1000 Hz in past science runs and are currently being commissioned in their advanced configurations [91, 7]. The rotational scheme is realized in torsion-bar antennas, which are considered as possible technology for sub-Hz GW detection [155, 69]. However, with achieved strain sensitivity of about 10−8 Hz−1/2 near 0.1 Hz, the torsion-bar detectors are far from the sensitivity we expect to be necessary for GW detection [88].
An external file that holds a picture, illustration, etc.
Object name is 41114_2016_3_Fig6.jpg
Figure 6
Sketches of the relative rotational and displacement measurement schemes.
Let us now return to the discussion of the previous sections on the role of seismic isolation and its impact on gravity response. Gravity strainmeters profit from seismic isolation more than gravimeters or gravity gradiometers. We have shown in Section 2.2 that seismically isolated gravimeters are effectively gravity gradiometers. So in this case, seismic isolation changes the response of the instrument in a fundamental way, and it does not make sense to talk of seismically isolated gravimeters. Seismic isolation could in principle be beneficial for gravity gradiometers (i.e., the acceleration of two test masses is measured with respect to a common rigid, seismically isolated reference frame), but the common-mode rejection of seismic noise (and gravity signals) due to the differential readout is typically so high that other instrumental noise becomes dominant. So it is possible that some gradiometers would profit from seismic isolation, but it is not generally true. Let us now consider the case of a gravity strainmeter. As explained in Section 2.3, we distinguish gradiometers and strainmeters by the distance of their test masses. For example, the distance of the LIGO or Virgo test masses is 4 km and 3 km respectively. Seismic noise and terrestrial gravity fluctuations are insignificantly correlated between the two test masses within the detectors’ most sensitive frequency band (above 10 Hz). Therefore, the approximation in Eq. (4) does not apply. Certainly, the distinction between gravity gradiometers and strainmeters remains somewhat arbitrary since at any frequency the approximation in Eq. (4) can hold for one type of gravity fluctuation, while it does not hold for another. Let us adopt a more practical definition at this point. Whenever the design of the instrument places the test masses as distant as possible from each other given current technology, then we call such an instrument strainmeter. In the following, we will discuss seismic isolation and gravity response for three strainmeter designs, the laser-interferometric, atom-interferometric, and superconducting strainmeters. It should be emphasized that the atom-interferometric and superconducting concepts are still in the beginning of their development and have not been realized yet with scientifically interesting sensitivities.
Laser-interferometric strainmeters The most sensitive gravity strainmeters, namely the large-scale GW detectors, use laser interferometry to read out the relative displacement between mirror pairs forming the test masses. Each test mass in these detectors is suspended from a seismically isolated platform, with the suspension itself providing additional seismic isolation. Section 2.1.1 introduced a simplified response and isolation model based on a harmonic oscillator characterized by a resonance frequency ω0 and viscous damping γ6. In a multi-stage isolation and suspension system as realized in GW detectors (see for example [37, 121]), coupling between multiple oscillators cannot be neglected, and is fundamental to the seismic isolation performance, but the basic features can still be explained with the simplified isolation and response model of Eqs. (2) and (3). The signal output of the interferometer is proportional to the relative displacement between test masses. Since seismic noise is approximately uncorrelated between two distant test masses, the differential measurement itself cannot reject seismic noise as in gravity gradiometers. Without seismic isolation, the dominant signal would be seismic strain, i.e., the distance change between test masses due to elastic deformation of the ground, with a value of about 10−15 Hz−1/2 at 50 Hz (assuming kilometer-scale arm lengths). At the same time, without seismically isolated test masses, the gravity signal can only come from the ground response to gravity fluctuations as described in Section 2.1.3, and from the Shapiro time delay as described in Section 2.1.2.
This Sunday was an exciting day at the flea market! Funnily enough, I predicted that we would find treasures. It was Colleen's last day of sort of summer vacation (meaning she would go back to working both jobs instead of just one). On top of that, we had plans to hang out with our friend, Lisa, in the afternoon. It's always on those busy days that you find cool stuff, but don't have the chance to enjoy it. I just knew we would finally have a fruitful weekend at the flea market on the day we had other plans in the afternoon. Despite the gloomy weather, there were exciting things to be found. The pieces of American Girl clothes were all super cheap--$1 to $2 each. The seller had seen us at another booth nearby looking at doll clothes. When we passed his table, he beckoned us over asking if we collected American Girl clothes. It seriously pays off sometimes to be very open about collecting dolls, because I never would have noticed the AG clothes on his table if he hadn't motioned us over. The coolest thing about these pieces is the fact that we completed two of our outfits. We FINALLY got the diaper and a pair of shoes to go with Billie Jean's "meet" outfit. Colleen also noticed that a pair of the shoes were the ones that went with Bitty Baby's Pretty Pink Outfits (both getups were ironically purchased at the flea market back in 2014). There were a few other AG odds and ends we snagged too, like Samantha's gaiters.
In the lower portion of the flea market, down the hill into a somewhat muddy area, we walked by a booth with vintage toys. I studied the table as we passed, but didn't see anything worthwhile. However, on the ground on the right side of the booth I spotted an open vintage case (looked like a hatbox almost) and a cardboard box beside it. At first it just looked like a bunch of figurines from the 60s. But as we started to continue onward, Skooter caught the corner of my eye. Immediately I pounced. It turns out there was another Skipper there too. She was a Twist 'N Turn Waist doll with a mutilated leg. Colleen picked her up too for purchase. The Ideal Toys dolls caught my attention as well. I knew they weren't Tammy, but I couldn't figure out if they were from her family/friend line or were different dolls altogether. When Colleen inquired about the price, the man said he'd unload it all for $20. Normally, with the amount of stuff and condition of it, we wouldn't have paid that much. But with 60s doll items, sometimes a singular dolly will be marked that much (I think Colleen paid $25 for her first Skooter doll at an antique store in a handmade outfit). It turns out that we got Misty, Tammy's friend, and Pepper, her little sister. Additionally, there was this awesome Supergirl included! Ironically, I almost left Todd behind because he was so grotesque. I had been wanting a Todd or Tutti doll since 2011, when we got back into collecting. 60s Barbies were some of the first thing that really excited us in those days. Todd was so foul and covered in goop, I mistook him for a freaky figurine. But something told me not to leave him behind. The moment I held him at home, I lost it when I realized who he was. Plus, he was wearing his original outfit!!! Who doesn't love a doll who needs all that TLC?!! The little doll house furniture will work well for our mini houses we've had since we were kids. It's from the Ideal Toys Petite Princess Furniture line. Many of the pieces were broken beyond repair, but these were the things we could work with. Plus, we found two 60s Barbie clothing items--Ken and Ricky's jackets (I seriously would have died if Ricky had been included...he's in the top ten cutest boy dolls ever list).
The two Babysitters Inc Skipper dolls were from the elderly couple we always buy from. I also snagged an Ever After High body donor from them. The poor girl had a missing eye that was sharpied over. But she was still wearing her outfit AND had both hands. It was cheaper buying the donor doll than getting a pair of hands from Mattel's Replacement Part website (this is why it makes more sense to use dolls who are too far gone as body/part donors rather than trying to fix them all).
As for the Cabbage Patch boy, he is without a doubt my favorite find. I was feeling the Cabbie Fever on Sunday...so was Colleen. At the flea market there are always sellers who put boxes and containers of random junk (literally) on the ground and on tables. They do not take any of it out, you are meant to dig through the bins. Usually I do a quick once over of these booths since they have boring things (like homeware). But as we finished an aisle, I saw a yarn head in a clear container. Immediately my doll senses tingled...I knew it was something cool. From a distance the hair color reminded me of my 1985 Twins. I tried to not get overly amped, knowing it was probably a very similar doll to one I already had. However, as I neared I noticed his legs looked abnormally long and like a slightly different texture. When I turned this guy over I saw the freckles and the cheaper looking head/hair. Immediately I thought to myself, "This is one of the foreign CPKs. Jesmar perhaps?" Sure enough he sported the Jesmar tag (his outfit is also original--tagged Jesmar too). The poor fella was foul, covered in stains and smelling like a dumpster. His condition alone warranted a rescue. The seller was super nice and only wanted $6 for him. I suppose he could have been cheaper, but since sellers at our flea market want $25 for a CPK doll usually, it was a deal. We named him Picasso, and he was a wonderful addition to our CPK family.
Dolls in photo from left to right:
-1984 Cabbage Patch Kids (Jesmar)
-1977 Charlie's Angels Sabrina
-1965 Tutti's Tiny Twin Todd
-1966 Pocketbook Doll Jan
-1967 Super Queen Supergirl
-1965 Tammy's Best Friend Misty
-1965 Tammy's Sister Pepper
-1964 Skipper's Friend Skooter
-1968 Twist 'N Turn Waist Skipper
-2018 Babysitters Inc. "Stroller" Skipper
-2019 Babysitters Inc. "Bedtime" Skipper
22 Kalliope is an M-type (partially known composition) asteroid, the predicted magnitude was 11.04, I found it to be close to that estimate using comparative stars in the view. Kalliope measures about 146 x 89 x 77 miles and also has a satellite names Linus which measures about 17 miles in diameter.
Tech Specs: Sky-Watcher 120ED, Canon 6D, single 60 second exposure at ISO 1250. Image Date: June 4, 2018. Location: The Dark Side Observatory, Weatherly, PA, USA
On night of August 26, 2017, I checked and there are only a little over 1,500 views to go; so this is going to happen sooner than I thought, like maybe August 27, 2017.
My thanks to each and every one of you for each and every one of them. Dorothy Delina Porter aka Pixel Packing Mama
Delina is pronounced with a long *i* sound if you are saying it out loud in your brain right now. Actually, it is still pronounced that way whether you are or are not saying it out loud in your brain. *grin*
"ARTSY sign for reaching 25 Million Views"
Weather reports predict the so called "Beast From The East" is due to revisit the UK over the next few days, today the 16th of March 2018 I visited Collieston Bay, its the first time I have witnessed the impact unusual weather has had on the area, it really was exhilarating and offered great photo opportunities.
Collieston is a small former fishing village on the North Sea coast in Aberdeenshire, Scotland. The village lies just north of the Sands of Forvie Special Protection Area, between Cruden Bay and Newburgh.
The earliest recorded history of Collieston is of the arrival of St Ternan, a Columban monk on a mission to convert the local picts to Christianity. There is, however, evidence that people lived here during much earlier times.
Collieston was established as a fishing village by the 16th century, and it provides the first safe harbour in over fifteen miles of beachesand dunes stretching north from Aberdeen.
Fishing for herring, haddock, whiting and codflourished in the 17th century and 18th century and was the foundation of Collieston's economy. The village became known for 'Collieston Speldings', salted and sun-dried haddock and whiting, a popular delicacy throughout Britain. As drift netting developed during the mid 19th century, the fishing began to decline and the focus of the industry shifted to places like Peterhead because the harbour at Collieston was too small to safely accommodate the larger boats needed.
The numerous sea caves in the nearby cliffs, and small coves with shingle beaches provided ideal terrain for smugglers. In the late 18th century it was estimated by the Excise that up to 8000 gallons of foreign spirits were being illegally landed in the area every month. In 1798, the notorious village smuggler, Phillip Kennedy, was killed by a blow from an exciseman's cutlass. His grave and tombstone still stands in the village graveyard.
A ship from the Spanish Armada, the Santa Caterina, carrying arms for the Earl of Erroll is said to have sunk just off the rocky point of St Catherine's Dub in 1594. In retaliation for the Earl's involvement in the Catholic plot against him, James VI blew up the Earl's castle which stood on the cliffs, a mile north of Collieston. The Earl went on to rebuild Slains Castle, six miles further up the coast, in 1597.
Collieston is now mainly a commuter village serving Aberdeen, and is largely given over to tourists during the summer months.
This brings us to Sir Doktor Professor Karl Raimund Popper’s attack on historicism. As I said in Chapter 5, this was his most significant insight, but it remains his least known. People who do not really know his work tend to focus on Popperian falsification, which addresses the verification or n...
#freeebook #freebook #ebook #book #Pomdy
Editor: taphuong
www.pomdy.com/book/the-black-swan/part-two-we-just-cant-p...
Predicting your call on the extra board can be a bit like long division, needlessly complicated and never really sure you got it right... until the phone rings. Today I thought I had it all dialed in, a phosphate train off the CSX coming north on the Superior Sub was showing ordered for 1230 out of Pokegama with no north pools available for several hours, got it. Just before that call was expected to come in, the phone rang. CN Crew Caller... well shit. “Mr Hennessy are you qualified on the T-Bird?” Yes. Yes I am. So off to Keenan I went. Left a little early in hopes of catching some iron ore action, timing was great as I paced a northbound limestone train from Alborn up to the range, unfortunately the sun was shit for northbound moves. Coming up to Fairlane I spied a load of pellets ready to head south, hedging my bets that he would get the light clearing the limestone train I parked. Sure enough the limestone blazed past and the pellet loader was headed to the docks in Duluth. These standard cab dash 8’s hold a special place in my heart as I made my first solo run as an engineer in one (CN 2019) on a Q119 several years prior. Most fans up here loath the toasters and covet the sd40’s, a sentiment I certainly understand but anywhere else in the country finding standard cab dash 8’a leading trains in 2021 would be constitute a miracle from christ himself... on the range, just another reason not to take the lens cap off. I should get out more often to shoot these dinosaurs, but CN is very good at finding ways to occupy my time and my daughters take up the rest. These old GE’s may have another couple years left in them but the kids only stay 5 and 3 for another couple months. Priorities... It does make me appreciate the rare moments trackside that I have however!
I first profiled the Goodman-Malone Taco Bell in early May 2020 (www.flickr.com/photos/l_dawg2000/49964758913/in/album-721...), and sure enough six months later, work is underway to transform the location to the latest Taco Bell look. Thankfully (and contrary to first reports), it looks as if this will just be a repaint and sign update however, as opposed to the somewhat more drastic changes that were done at the similar Church Rd. location. Sadly, that remodel wiped away much of that Taco Bell's original, very cool exterior traits.
I'm going to keep adding these to my general "Taco Bell Tour" album, instead of giving this location it's own space, since I don't believe there will be much reason to do dozens and dozens of photos of this exterior refresh. But heck, might as well start doing a few photo tags at least :P
____________________________________
Taco Bell, 2008-built, Goodman Rd. at Malone Rd., Southaven MS
Weather reports predict the so called "Beast From The East" is due to revisit the UK over the next few days, today the 16th of March 2018 I visited Collieston Bay, its the first time I have witnessed the impact unusual weather has had on the area, it really was exhilarating and offered great photo opportunities.
Collieston is a small former fishing village on the North Sea coast in Aberdeenshire, Scotland. The village lies just north of the Sands of Forvie Special Protection Area, between Cruden Bay and Newburgh.
The earliest recorded history of Collieston is of the arrival of St Ternan, a Columban monk on a mission to convert the local picts to Christianity. There is, however, evidence that people lived here during much earlier times.
Collieston was established as a fishing village by the 16th century, and it provides the first safe harbour in over fifteen miles of beachesand dunes stretching north from Aberdeen.
Fishing for herring, haddock, whiting and codflourished in the 17th century and 18th century and was the foundation of Collieston's economy. The village became known for 'Collieston Speldings', salted and sun-dried haddock and whiting, a popular delicacy throughout Britain. As drift netting developed during the mid 19th century, the fishing began to decline and the focus of the industry shifted to places like Peterhead because the harbour at Collieston was too small to safely accommodate the larger boats needed.
The numerous sea caves in the nearby cliffs, and small coves with shingle beaches provided ideal terrain for smugglers. In the late 18th century it was estimated by the Excise that up to 8000 gallons of foreign spirits were being illegally landed in the area every month. In 1798, the notorious village smuggler, Phillip Kennedy, was killed by a blow from an exciseman's cutlass. His grave and tombstone still stands in the village graveyard.
A ship from the Spanish Armada, the Santa Caterina, carrying arms for the Earl of Erroll is said to have sunk just off the rocky point of St Catherine's Dub in 1594. In retaliation for the Earl's involvement in the Catholic plot against him, James VI blew up the Earl's castle which stood on the cliffs, a mile north of Collieston. The Earl went on to rebuild Slains Castle, six miles further up the coast, in 1597.
Collieston is now mainly a commuter village serving Aberdeen, and is largely given over to tourists during the summer months.
just because……
my SIL dearest gave me this for some special occasion and we both think it’s so pretty. (And not just because it’s blue!)
CMWD_blue
Btb, I figured out how to make this my “screensaver” welcoming screen on iPhone Able— how cool is that!!
It’s actually calledasto glass
As predicted by the prophet Zacharie Delaplaya, the Four Surfers of the Apocalypso will soon emerge to sound the death knell of summertime. Splitting the sea foam from atop their mounts, they’ll arrive at great speed to announce to the sun-lovers and terrace dwellers the end of this lovely season. So enjoy the time you have left to knock back a pint and live each day as if it was the last act. Carpe diem!
Bodie is a ghost town in the Bodie Hills east of the Sierra Nevada mountain range in Mono County, California, United States. It is about 75 miles (121 km) southeast of Lake Tahoe, and 12 mi (19 km) east-southeast of Bridgeport, at an elevation of 8,379 feet (2554 m). Bodie became a boom town in 1876 (146 years ago) after the discovery of a profitable line of gold; by 1879 it had a population of 7,000–10,000.
The town went into decline in the subsequent decades and came to be described as a ghost town by 1915 (107 years ago). The U.S. Department of the Interior recognizes the designated Bodie Historic District as a National Historic Landmark.
Also registered as a California Historical Landmark, the ghost town officially was established as Bodie State Historic Park in 1962. It receives about 200,000 visitors yearly. Bodie State Historic Park is partly supported by the Bodie Foundation.
Bodie began as a mining camp of little note following the discovery of gold in 1859 by a group of prospectors, including W. S. Bodey. Bodey died in a blizzard the following November while making a supply trip to Monoville (near present-day Mono City), never getting to see the rise of the town that was named after him. According to area pioneer Judge J. G. McClinton, the district's name was changed from "Bodey," "Body," and a few other phonetic variations, to "Bodie," after a painter in the nearby boomtown of Aurora, lettered a sign "Bodie Stables".
Gold discovered at Bodie coincided with the discovery of silver at nearby Aurora (thought to be in California, later found to be Nevada), and the distant Comstock Lode beneath Virginia City, Nevada. But while these two towns boomed, interest in Bodie remained lackluster. By 1868 only two companies had built stamp mills at Bodie, and both had failed.
In 1876, the Standard Company discovered a profitable deposit of gold-bearing ore, which transformed Bodie from an isolated mining camp comprising a few prospectors and company employees to a Wild West boomtown. Rich discoveries in the adjacent Bodie Mine during 1878 attracted even more hopeful people. By 1879, Bodie had a population of approximately 7,000–10,000 people and around 2,000 buildings. One legend says that in 1880, Bodie was California's second or third largest city. but the U.S. Census of that year disproves this. Over the years 1860-1941 Bodie's mines produced gold and silver valued at an estimated US$34 million (in 1986 dollars, or $85 million in 2021).
Bodie boomed from late 1877 through mid– to late 1880. The first newspaper, The Standard Pioneer Journal of Mono County, published its first edition on October 10, 1877. Starting as a weekly, it soon expanded publication to three times a week. It was also during this time that a telegraph line was built which connected Bodie with Bridgeport and Genoa, Nevada. California and Nevada newspapers predicted Bodie would become the next Comstock Lode. Men from both states were lured to Bodie by the prospect of another bonanza.
Gold bullion from the town's nine stamp mills was shipped to Carson City, Nevada, by way of Aurora, Wellington and Gardnerville. Most shipments were accompanied by armed guards. After the bullion reached Carson City, it was delivered to the mint there, or sent by rail to the mint in San Francisco.
As a bustling gold mining center, Bodie had the amenities of larger towns, including a Wells Fargo Bank, four volunteer fire companies, a brass band, railroad, miners' and mechanics' union, several daily newspapers, and a jail. At its peak, 65 saloons lined Main Street, which was a mile long. Murders, shootouts, barroom brawls, and stagecoach holdups were regular occurrences.
As with other remote mining towns, Bodie had a popular, though clandestine, red light district on the north end of town. There is an unsubstantiated story of Rosa May, a prostitute who, in the style of Florence Nightingale, came to the aid of the town menfolk when a serious epidemic struck the town at the height of its boom. She is credited with giving life-saving care to many, but after she died, was buried outside the cemetery fence.
Bodie had a Chinatown, the main street of which ran at a right angle to Bodie's Main Street. At one point it had several hundred Chinese residents and a Taoist temple. Opium dens were plentiful in this area.
Bodie also had a cemetery on the outskirts of town and a nearby mortuary. It is the only building in the town built of red brick three courses thick, most likely for insulation to keep the air temperature steady during the cold winters and hot summers. The cemetery includes a Miners Union section, and a cenotaph erected to honor President James A. Garfield. The Bodie Boot Hill was located outside of the official city cemetery.
On Main Street stands the Miners Union Hall, which was the meeting place for labor unions. It also served as an entertainment center that hosted dances, concerts, plays, and school recitals. It now serves as a museum.
The first signs of decline appeared in 1880 and became obvious toward the end of the year. Promising mining booms in Butte, Montana; Tombstone, Arizona; and Utah lured men away from Bodie. The get-rich-quick, single miners who came to the town in the 1870s moved on to these other booms, and Bodie developed into a family-oriented community. In 1882 residents built the Methodist Church (which still stands) and the Roman Catholic Church (burned 1928). Despite the population decline, the mines were flourishing, and in 1881 Bodie's ore production was recorded at a high of $3.1 million. Also in 1881, a narrow-gauge railroad was built called the Bodie Railway & Lumber Company, bringing lumber, cordwood, and mine timbers to the mining district from Mono Mills south of Mono Lake.
During the early 1890s, Bodie enjoyed a short revival from technological advancements in the mines that continued to support the town. In 1890, the recently invented cyanide process promised to recover gold and silver from discarded mill tailings and from low-grade ore bodies that had been passed over. In 1892, the Standard Company built its own hydroelectric plant approximately 13 miles (20.9 km) away at Dynamo Pond. The plant developed a maximum of 130 horsepower (97 kW) and 3,530 volts alternating current (AC) to power the company's 20-stamp mill. This pioneering installation marked the country's first transmissions of electricity over a long distance.
In 1910, the population was recorded at 698 people, which were predominantly families who decided to stay in Bodie instead of moving on to other prosperous strikes.
The first signs of an official decline occurred in 1912 with the printing of the last Bodie newspaper, The Bodie Miner. In a 1913 book titled California Tourist Guide and Handbook: Authentic Description of Routes of Travel and Points of Interest in California, the authors, Wells and Aubrey Drury, described Bodie as a "mining town, which is the center of a large mineral region". They referred to two hotels and a railroad operating there. In 1913, the Standard Consolidated Mine closed.
Mining profits in 1914 were at a low of $6,821. James S. Cain bought everything from the town lots to the mining claims, and reopened the Standard mill to former employees, which resulted in an over $100,000 profit in 1915. However, this financial growth was not in time to stop the town's decline. In 1917, the Bodie Railway was abandoned and its iron tracks were scrapped.
The last mine closed in 1942, due to War Production Board order L-208, shutting down all non-essential gold mines in the United States during World War II. Mining never resumed after the war.
Bodie was first described as a "ghost town" in 1915. In a time when auto travel was on the rise, many travelers reached Bodie via automobiles. The San Francisco Chronicle published an article in 1919 to dispute the "ghost town" label.
By 1920, Bodie's population was recorded by the US Federal Census at a total of 120 people. Despite the decline and a severe fire in the business district in 1932, Bodie had permanent residents through nearly half of the 20th century. A post office operated at Bodie from 1877 to 1942
In the 1940s, the threat of vandalism faced the ghost town. The Cain family, who owned much of the land, hired caretakers to protect and to maintain the town's structures. Martin Gianettoni, one of the last three people living in Bodie in 1943, was a caretaker.
Bodie is now an authentic Wild West ghost town.
The town was designated a National Historic Landmark in 1961, and in 1962 the state legislature authorized creation of Bodie State Historic Park. A total of 170 buildings remained. Bodie has been named as California's official state gold rush ghost town.
Visitors arrive mainly via SR 270, which runs from US 395 near Bridgeport to the west; the last three miles of it is a dirt road. There is also a road to SR 167 near Mono Lake in the south, but this road is extremely rough, with more than 10 miles of dirt track in a bad state of repair. Due to heavy snowfall, the roads to Bodie are usually closed in winter .
Today, Bodie is preserved in a state of arrested decay. Only a small part of the town survived, with about 110 structures still standing, including one of many once operational gold mills. Visitors can walk the deserted streets of a town that once was a bustling area of activity. Interiors remain as they were left and stocked with goods. Littered throughout the park, one can find small shards of china dishes, square nails and an occasional bottle, but removing these items is against the rules of the park.
The California State Parks' ranger station is located in one of the original homes on Green Street.
In 2009 and again in 2010, Bodie was scheduled to be closed. The California state legislature worked out a budget compromise that enabled the state's Parks Closure Commission to keep it open. As of 2022, the park is still operating, now administered by the Bodie Foundation.
California is a state in the Western United States, located along the Pacific Coast. With nearly 39.2 million residents across a total area of approximately 163,696 square miles (423,970 km2), it is the most populous U.S. state and the 3rd largest by area. It is also the most populated subnational entity in North America and the 34th most populous in the world. The Greater Los Angeles area and the San Francisco Bay Area are the nation's second and fifth most populous urban regions respectively, with the former having more than 18.7 million residents and the latter having over 9.6 million. Sacramento is the state's capital, while Los Angeles is the most populous city in the state and the second most populous city in the country. San Francisco is the second most densely populated major city in the country. Los Angeles County is the country's most populous, while San Bernardino County is the largest county by area in the country. California borders Oregon to the north, Nevada and Arizona to the east, the Mexican state of Baja California to the south; and has a coastline along the Pacific Ocean to the west.
The economy of the state of California is the largest in the United States, with a $3.4 trillion gross state product (GSP) as of 2022. It is the largest sub-national economy in the world. If California were a sovereign nation, it would rank as the world's fifth-largest economy as of 2022, behind Germany and ahead of India, as well as the 37th most populous. The Greater Los Angeles area and the San Francisco Bay Area are the nation's second- and third-largest urban economies ($1.0 trillion and $0.5 trillion respectively as of 2020). The San Francisco Bay Area Combined Statistical Area had the nation's highest gross domestic product per capita ($106,757) among large primary statistical areas in 2018, and is home to five of the world's ten largest companies by market capitalization and four of the world's ten richest people.
Prior to European colonization, California was one of the most culturally and linguistically diverse areas in pre-Columbian North America and contained the highest Native American population density north of what is now Mexico. European exploration in the 16th and 17th centuries led to the colonization of California by the Spanish Empire. In 1804, it was included in Alta California province within the Viceroyalty of New Spain. The area became a part of Mexico in 1821, following its successful war for independence, but was ceded to the United States in 1848 after the Mexican–American War. The California Gold Rush started in 1848 and led to dramatic social and demographic changes, including large-scale immigration into California, a worldwide economic boom, and the California genocide of indigenous people. The western portion of Alta California was then organized and admitted as the 31st state on September 9, 1850, following the Compromise of 1850.
Notable contributions to popular culture, for example in entertainment and sports, have their origins in California. The state also has made noteworthy contributions in the fields of communication, information, innovation, environmentalism, economics, and politics. It is the home of Hollywood, the oldest and one of the largest film industries in the world, which has had a profound influence upon global entertainment. It is considered the origin of the hippie counterculture, beach and car culture, and the personal computer, among other innovations. The San Francisco Bay Area and the Greater Los Angeles Area are widely seen as the centers of the global technology and film industries, respectively. California's economy is very diverse: 58% of it is based on finance, government, real estate services, technology, and professional, scientific, and technical business services. Although it accounts for only 1.5% of the state's economy, California's agriculture industry has the highest output of any U.S. state. California's ports and harbors handle about a third of all U.S. imports, most originating in Pacific Rim international trade.
The state's extremely diverse geography ranges from the Pacific Coast and metropolitan areas in the west to the Sierra Nevada mountains in the east, and from the redwood and Douglas fir forests in the northwest to the Mojave Desert in the southeast. The Central Valley, a major agricultural area, dominates the state's center. California is well known for its warm Mediterranean climate and monsoon seasonal weather. The large size of the state results in climates that vary from moist temperate rainforest in the north to arid desert in the interior, as well as snowy alpine in the mountains.
Settled by successive waves of arrivals during at least the last 13,000 years, California was one of the most culturally and linguistically diverse areas in pre-Columbian North America. Various estimates of the native population have ranged from 100,000 to 300,000. The indigenous peoples of California included more than 70 distinct ethnic groups, inhabiting environments from mountains and deserts to islands and redwood forests. These groups were also diverse in their political organization, with bands, tribes, villages, and on the resource-rich coasts, large chiefdoms, such as the Chumash, Pomo and Salinan. Trade, intermarriage and military alliances fostered social and economic relationships between many groups.
The first Europeans to explore the coast of California were the members of a Spanish maritime expedition led by Portuguese captain Juan Rodríguez Cabrillo in 1542. Cabrillo was commissioned by Antonio de Mendoza, the Viceroy of New Spain, to lead an expedition up the Pacific coast in search of trade opportunities; they entered San Diego Bay on September 28, 1542, and reached at least as far north as San Miguel Island. Privateer and explorer Francis Drake explored and claimed an undefined portion of the California coast in 1579, landing north of the future city of San Francisco. Sebastián Vizcaíno explored and mapped the coast of California in 1602 for New Spain, putting ashore in Monterey. Despite the on-the-ground explorations of California in the 16th century, Rodríguez's idea of California as an island persisted. Such depictions appeared on many European maps well into the 18th century.
The Portolá expedition of 1769-70 was a pivotal event in the Spanish colonization of California, resulting in the establishment of numerous missions, presidios, and pueblos. The military and civil contingent of the expedition was led by Gaspar de Portolá, who traveled over land from Sonora into California, while the religious component was headed by Junípero Serra, who came by sea from Baja California. In 1769, Portolá and Serra established Mission San Diego de Alcalá and the Presidio of San Diego, the first religious and military settlements founded by the Spanish in California. By the end of the expedition in 1770, they would establish the Presidio of Monterey and Mission San Carlos Borromeo de Carmelo on Monterey Bay.
After the Portolà expedition, Spanish missionaries led by Father-President Serra set out to establish 21 Spanish missions of California along El Camino Real ("The Royal Road") and along the Californian coast, 16 sites of which having been chosen during the Portolá expedition. Numerous major cities in California grew out of missions, including San Francisco (Mission San Francisco de Asís), San Diego (Mission San Diego de Alcalá), Ventura (Mission San Buenaventura), or Santa Barbara (Mission Santa Barbara), among others.
Juan Bautista de Anza led a similarly important expedition throughout California in 1775–76, which would extend deeper into the interior and north of California. The Anza expedition selected numerous sites for missions, presidios, and pueblos, which subsequently would be established by settlers. Gabriel Moraga, a member of the expedition, would also christen many of California's prominent rivers with their names in 1775–1776, such as the Sacramento River and the San Joaquin River. After the expedition, Gabriel's son, José Joaquín Moraga, would found the pueblo of San Jose in 1777, making it the first civilian-established city in California.
The Spanish founded Mission San Juan Capistrano in 1776, the third to be established of the Californian missions.
During this same period, sailors from the Russian Empire explored along the northern coast of California. In 1812, the Russian-American Company established a trading post and small fortification at Fort Ross on the North Coast. Fort Ross was primarily used to supply Russia's Alaskan colonies with food supplies. The settlement did not meet much success, failing to attract settlers or establish long term trade viability, and was abandoned by 1841.
During the War of Mexican Independence, Alta California was largely unaffected and uninvolved in the revolution, though many Californios supported independence from Spain, which many believed had neglected California and limited its development. Spain's trade monopoly on California had limited the trade prospects of Californians. Following Mexican independence, Californian ports were freely able to trade with foreign merchants. Governor Pablo Vicente de Solá presided over the transition from Spanish colonial rule to independent.
In 1821, the Mexican War of Independence gave the Mexican Empire (which included California) independence from Spain. For the next 25 years, Alta California remained a remote, sparsely populated, northwestern administrative district of the newly independent country of Mexico, which shortly after independence became a republic. The missions, which controlled most of the best land in the state, were secularized by 1834 and became the property of the Mexican government. The governor granted many square leagues of land to others with political influence. These huge ranchos or cattle ranches emerged as the dominant institutions of Mexican California. The ranchos developed under ownership by Californios (Hispanics native of California) who traded cowhides and tallow with Boston merchants. Beef did not become a commodity until the 1849 California Gold Rush.
From the 1820s, trappers and settlers from the United States and Canada began to arrive in Northern California. These new arrivals used the Siskiyou Trail, California Trail, Oregon Trail and Old Spanish Trail to cross the rugged mountains and harsh deserts in and surrounding California. The early government of the newly independent Mexico was highly unstable, and in a reflection of this, from 1831 onwards, California also experienced a series of armed disputes, both internal and with the central Mexican government. During this tumultuous political period Juan Bautista Alvarado was able to secure the governorship during 1836–1842. The military action which first brought Alvarado to power had momentarily declared California to be an independent state, and had been aided by Anglo-American residents of California, including Isaac Graham. In 1840, one hundred of those residents who did not have passports were arrested, leading to the Graham Affair, which was resolved in part with the intercession of Royal Navy officials.
One of the largest ranchers in California was John Marsh. After failing to obtain justice against squatters on his land from the Mexican courts, he determined that California should become part of the United States. Marsh conducted a letter-writing campaign espousing the California climate, the soil, and other reasons to settle there, as well as the best route to follow, which became known as "Marsh's route". His letters were read, reread, passed around, and printed in newspapers throughout the country, and started the first wagon trains rolling to California. He invited immigrants to stay on his ranch until they could get settled, and assisted in their obtaining passports.
After ushering in the period of organized emigration to California, Marsh became involved in a military battle between the much-hated Mexican general, Manuel Micheltorena and the California governor he had replaced, Juan Bautista Alvarado. The armies of each met at the Battle of Providencia near Los Angeles. Marsh had been forced against his will to join Micheltorena's army. Ignoring his superiors, during the battle, he signaled the other side for a parley. There were many settlers from the United States fighting on both sides. He convinced these men that they had no reason to be fighting each other. As a result of Marsh's actions, they abandoned the fight, Micheltorena was defeated, and California-born Pio Pico was returned to the governorship. This paved the way to California's ultimate acquisition by the United States.
In 1846, a group of American settlers in and around Sonoma rebelled against Mexican rule during the Bear Flag Revolt. Afterward, rebels raised the Bear Flag (featuring a bear, a star, a red stripe and the words "California Republic") at Sonoma. The Republic's only president was William B. Ide,[65] who played a pivotal role during the Bear Flag Revolt. This revolt by American settlers served as a prelude to the later American military invasion of California and was closely coordinated with nearby American military commanders.
The California Republic was short-lived; the same year marked the outbreak of the Mexican–American War (1846–48).
Commodore John D. Sloat of the United States Navy sailed into Monterey Bay in 1846 and began the U.S. military invasion of California, with Northern California capitulating in less than a month to the United States forces. In Southern California, Californios continued to resist American forces. Notable military engagements of the conquest include the Battle of San Pasqual and the Battle of Dominguez Rancho in Southern California, as well as the Battle of Olómpali and the Battle of Santa Clara in Northern California. After a series of defensive battles in the south, the Treaty of Cahuenga was signed by the Californios on January 13, 1847, securing a censure and establishing de facto American control in California.
Following the Treaty of Guadalupe Hidalgo (February 2, 1848) that ended the war, the westernmost portion of the annexed Mexican territory of Alta California soon became the American state of California, and the remainder of the old territory was then subdivided into the new American Territories of Arizona, Nevada, Colorado and Utah. The even more lightly populated and arid lower region of old Baja California remained as a part of Mexico. In 1846, the total settler population of the western part of the old Alta California had been estimated to be no more than 8,000, plus about 100,000 Native Americans, down from about 300,000 before Hispanic settlement in 1769.
In 1848, only one week before the official American annexation of the area, gold was discovered in California, this being an event which was to forever alter both the state's demographics and its finances. Soon afterward, a massive influx of immigration into the area resulted, as prospectors and miners arrived by the thousands. The population burgeoned with United States citizens, Europeans, Chinese and other immigrants during the great California Gold Rush. By the time of California's application for statehood in 1850, the settler population of California had multiplied to 100,000. By 1854, more than 300,000 settlers had come. Between 1847 and 1870, the population of San Francisco increased from 500 to 150,000.
The seat of government for California under Spanish and later Mexican rule had been located in Monterey from 1777 until 1845. Pio Pico, the last Mexican governor of Alta California, had briefly moved the capital to Los Angeles in 1845. The United States consulate had also been located in Monterey, under consul Thomas O. Larkin.
In 1849, a state Constitutional Convention was first held in Monterey. Among the first tasks of the convention was a decision on a location for the new state capital. The first full legislative sessions were held in San Jose (1850–1851). Subsequent locations included Vallejo (1852–1853), and nearby Benicia (1853–1854); these locations eventually proved to be inadequate as well. The capital has been located in Sacramento since 1854 with only a short break in 1862 when legislative sessions were held in San Francisco due to flooding in Sacramento. Once the state's Constitutional Convention had finalized its state constitution, it applied to the U.S. Congress for admission to statehood. On September 9, 1850, as part of the Compromise of 1850, California became a free state and September 9 a state holiday.
During the American Civil War (1861–1865), California sent gold shipments eastward to Washington in support of the Union. However, due to the existence of a large contingent of pro-South sympathizers within the state, the state was not able to muster any full military regiments to send eastwards to officially serve in the Union war effort. Still, several smaller military units within the Union army were unofficially associated with the state of California, such as the "California 100 Company", due to a majority of their members being from California.
At the time of California's admission into the Union, travel between California and the rest of the continental United States had been a time-consuming and dangerous feat. Nineteen years later, and seven years after it was greenlighted by President Lincoln, the First transcontinental railroad was completed in 1869. California was then reachable from the eastern States in a week's time.
Much of the state was extremely well suited to fruit cultivation and agriculture in general. Vast expanses of wheat, other cereal crops, vegetable crops, cotton, and nut and fruit trees were grown (including oranges in Southern California), and the foundation was laid for the state's prodigious agricultural production in the Central Valley and elsewhere.
In the nineteenth century, a large number of migrants from China traveled to the state as part of the Gold Rush or to seek work. Even though the Chinese proved indispensable in building the transcontinental railroad from California to Utah, perceived job competition with the Chinese led to anti-Chinese riots in the state, and eventually the US ended migration from China partially as a response to pressure from California with the 1882 Chinese Exclusion Act.
Under earlier Spanish and Mexican rule, California's original native population had precipitously declined, above all, from Eurasian diseases to which the indigenous people of California had not yet developed a natural immunity. Under its new American administration, California's harsh governmental policies towards its own indigenous people did not improve. As in other American states, many of the native inhabitants were soon forcibly removed from their lands by incoming American settlers such as miners, ranchers, and farmers. Although California had entered the American union as a free state, the "loitering or orphaned Indians" were de facto enslaved by their new Anglo-American masters under the 1853 Act for the Government and Protection of Indians. There were also massacres in which hundreds of indigenous people were killed.
Between 1850 and 1860, the California state government paid around 1.5 million dollars (some 250,000 of which was reimbursed by the federal government) to hire militias whose purpose was to protect settlers from the indigenous populations. In later decades, the native population was placed in reservations and rancherias, which were often small and isolated and without enough natural resources or funding from the government to sustain the populations living on them. As a result, the rise of California was a calamity for the native inhabitants. Several scholars and Native American activists, including Benjamin Madley and Ed Castillo, have described the actions of the California government as a genocide.
In the twentieth century, thousands of Japanese people migrated to the US and California specifically to attempt to purchase and own land in the state. However, the state in 1913 passed the Alien Land Act, excluding Asian immigrants from owning land. During World War II, Japanese Americans in California were interned in concentration camps such as at Tule Lake and Manzanar. In 2020, California officially apologized for this internment.
Migration to California accelerated during the early 20th century with the completion of major transcontinental highways like the Lincoln Highway and Route 66. In the period from 1900 to 1965, the population grew from fewer than one million to the greatest in the Union. In 1940, the Census Bureau reported California's population as 6.0% Hispanic, 2.4% Asian, and 89.5% non-Hispanic white.
To meet the population's needs, major engineering feats like the California and Los Angeles Aqueducts; the Oroville and Shasta Dams; and the Bay and Golden Gate Bridges were built across the state. The state government also adopted the California Master Plan for Higher Education in 1960 to develop a highly efficient system of public education.
Meanwhile, attracted to the mild Mediterranean climate, cheap land, and the state's wide variety of geography, filmmakers established the studio system in Hollywood in the 1920s. California manufactured 8.7 percent of total United States military armaments produced during World War II, ranking third (behind New York and Michigan) among the 48 states. California however easily ranked first in production of military ships during the war (transport, cargo, [merchant ships] such as Liberty ships, Victory ships, and warships) at drydock facilities in San Diego, Los Angeles, and the San Francisco Bay Area. After World War II, California's economy greatly expanded due to strong aerospace and defense industries, whose size decreased following the end of the Cold War. Stanford University and its Dean of Engineering Frederick Terman began encouraging faculty and graduates to stay in California instead of leaving the state, and develop a high-tech region in the area now known as Silicon Valley. As a result of these efforts, California is regarded as a world center of the entertainment and music industries, of technology, engineering, and the aerospace industry, and as the United States center of agricultural production. Just before the Dot Com Bust, California had the fifth-largest economy in the world among nations.
In the mid and late twentieth century, a number of race-related incidents occurred in the state. Tensions between police and African Americans, combined with unemployment and poverty in inner cities, led to violent riots, such as the 1965 Watts riots and 1992 Rodney King riots. California was also the hub of the Black Panther Party, a group known for arming African Americans to defend against racial injustice and for organizing free breakfast programs for schoolchildren. Additionally, Mexican, Filipino, and other migrant farm workers rallied in the state around Cesar Chavez for better pay in the 1960s and 1970s.
During the 20th century, two great disasters happened in California. The 1906 San Francisco earthquake and 1928 St. Francis Dam flood remain the deadliest in U.S. history.
Although air pollution problems have been reduced, health problems associated with pollution have continued. The brown haze known as "smog" has been substantially abated after the passage of federal and state restrictions on automobile exhaust.
An energy crisis in 2001 led to rolling blackouts, soaring power rates, and the importation of electricity from neighboring states. Southern California Edison and Pacific Gas and Electric Company came under heavy criticism.
Housing prices in urban areas continued to increase; a modest home which in the 1960s cost $25,000 would cost half a million dollars or more in urban areas by 2005. More people commuted longer hours to afford a home in more rural areas while earning larger salaries in the urban areas. Speculators bought houses they never intended to live in, expecting to make a huge profit in a matter of months, then rolling it over by buying more properties. Mortgage companies were compliant, as everyone assumed the prices would keep rising. The bubble burst in 2007–8 as housing prices began to crash and the boom years ended. Hundreds of billions in property values vanished and foreclosures soared as many financial institutions and investors were badly hurt.
In the twenty-first century, droughts and frequent wildfires attributed to climate change have occurred in the state. From 2011 to 2017, a persistent drought was the worst in its recorded history. The 2018 wildfire season was the state's deadliest and most destructive, most notably Camp Fire.
Although air pollution problems have been reduced, health problems associated with pollution have continued. The brown haze that is known as "smog" has been substantially abated thanks to federal and state restrictions on automobile exhaust.
One of the first confirmed COVID-19 cases in the United States that occurred in California was first of which was confirmed on January 26, 2020. Meaning, all of the early confirmed cases were persons who had recently travelled to China in Asia, as testing was restricted to this group. On this January 29, 2020, as disease containment protocols were still being developed, the U.S. Department of State evacuated 195 persons from Wuhan, China aboard a chartered flight to March Air Reserve Base in Riverside County, and in this process, it may have granted and conferred to escalated within the land and the US at cosmic. On February 5, 2020, the U.S. evacuated 345 more citizens from Hubei Province to two military bases in California, Travis Air Force Base in Solano County and Marine Corps Air Station Miramar, San Diego, where they were quarantined for 14 days. A state of emergency was largely declared in this state of the nation on March 4, 2020, and as of February 24, 2021, remains in effect. A mandatory statewide stay-at-home order was issued on March 19, 2020, due to increase, which was ended on January 25, 2021, allowing citizens to return to normal life. On April 6, 2021, the state announced plans to fully reopen the economy by June 15, 2021.