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My first attempt at a snowflake macro, far far from perfect but I hope to improve it in future.
I reversed my 18-70mm lens and brought loose snow inside my house. Took about 150 shots to realize that no matter how fast I work to focus on my primitive setup, the snowflakes always melt before I get any decent shot. That meant I have to go outside into the freezing temperature, with my tripod, light source, tweezers for collecting them and so on. You would think that among the millions of snowflakes at least one would be occasionally focused. Not so simple. I saw lots of hexagonal symmetry but nothing undamaged and focused. The best I got is this and now I am waiting for a day when the weather cooperates with bigger snowflakes that are easier to catch and position:
It's Friday evening and she is going to a party to celebrate one of her husbands friends birthdays. She had spent the whole day at work as a secretary in a law firm and her feet were killing her from the 120mm So Kate's that were her "work shoe". As such she decided she would wear flats to the party tonight, knowing she would likely spend the whole time on her feet. She knew she should be wearing her heels but also new her feet desperately needed a break.
Her husband, however, had other ideas. He took one look at her as she came down stairs in her flat shoes and declared that they would not do at all and he would pick some out for her.
To her dismay he picks out her highest gold sandals. Not only that, he also says she needs to be taught a lesson so that she always remembers to wear her heels in future.
He locks her up in her heels for an hour before they leave for the party. It's very tiring for her already burning feet but secretly she is pleased to be held to a high standard and knows she looks great in them.
She is less pleased when he announces to her that he has decided to cancel the taxi to the party and they'll be walking the 1.5 miles to the venue instead. Not to worry he is says. You can lean on me if you need to.
She asks if she is allowed a 10 minute break off her feet before they start walking... He is undecided...
Or I would be if I were to make sure that I had tucked my blouse in properly - goes to show how unused I am to this more formal look - I shall try harder in future!!!!!!!!!!.
Few days ago I saw PleaseYesPlease's fantastic VW T1 Single Cab and loved it. I always wanted to build one, but this last weekend got me really motivated when I saw this Volkswide by Robert Design.
I tried to capture the overall shape and with my limited teal parts I like how it turned out. Will definitely modify it more in future, once I got the right parts. Usually all my car build attempts fail, but this one I'll keep :)
Inchagoill Island is said to be where St.. Patrick converted the Druids to Christianity. These ruins, including the cemetary are from the 5th Century (400's) A.D., although in future years many high members of the clergy and royalty were buried there.
This is a shot I took on a recent trip to Lake Tahoe. I have wanted to capture the Milky Way for quite some time and finally decided to try my luck on this moonless night on the beach. After being warned by a local ranger about recent bear activity in the area, I was a bit nervous on my hike out to this location by myself. Although the black bears that populate this area have never attacked a person to the best of my knowledge, an encounter with one in pitch black darkness would be quite the adrenaline rush to say the least. Luckily I made it through this shoot with no bear encounters. I am happy with my first attempt at capturing the Milky Way but I still have much more to learn and improve in future attempts. Thank you for looking!
Letter reads:
J. H. TODD & SON,
IMPORTERS
GENERAL MERCHANDISE.
P. O. Drawer 21.
Victoria, B.C., Nov 12th 1888
Mr. Eddy McKenzie / Clover Valley
We were sorry not to have seen both yourself & brother before you left Richm???? - as we had intended making you a small present in consideration of you being not only a very good worker - but a good BOY and we here with enclose our cheque for $10 as a present hoping that if we have further ??????? they may be as agreeable in future as the past.
We are yours truly
J.H. Todd & Son
P.S. - We shall hope to have both you & Harry again next season. Please advice soonest by return mail & oblige J.H.T. & S
JACOB HUNTER TODD, businessman and politician; b. 17 March 1827 near Brampton, Upper Canada, son of John Todd and Isabella Hunter; m. first 25 Jan. 1854, in Brampton, Anne Fox (d. 1866), and they had two sons and two daughters, of whom a son and a daughter survived childhood; m. there secondly 24 March 1873 Rosanna Wigley, and they had five sons, of whom three died young, and two daughters; d. 10 Aug. 1899 in Victoria, B.C.
According to descendants of Jacob Hunter Todd, his father, an Irish farmer who spent more time fox hunting than farming, immigrated to the United States in 1816 and was joined by his wife two years later. He worked in New York City at several trades before moving in 1820 to a farm in Trafalgar Township, Upper Canada, preferring, in the words of the Canada Christian Advocate, “life under British rule.” Little is known of the first three decades of Jacob’s life; he received some basic education and then worked on the family farm. Later he and a brother sold sewing-machines from house to house, travelling by horse and buckboard. It was a modest enterprise with modest returns.
Todd and his wife Anne moved to Victoria, Vancouver Island, in 1862, the year the town was incorporated. Jacob went first, arriving in May after a five-week journey by train across the United States and by steamer from San Francisco to Esquimalt, Vancouver Island. It is possible that he returned to Upper Canada later that year to accompany his wife and children to the west; their two-year-old daughter apparently died on the ship from San Francisco.
With characteristic energy, Todd adopted advances in the fishing industry. He owned scores of small fishing boats, which he leased to fishermen in return for a percentage of the catch. Tugs were purchased to tow the boats from the canneries or villages to the fishing grounds. Steam vessels were constructed to take the catch to more distant canneries. Markets were developed in Great Britain and Europe, and his “Horseshoe” brand won prizes at London’s Crystal Palace exhibition and at other world fairs. Through the efforts of the Todds as well as others in the industry, canned salmon became a popular food, particularly in Great Britain, where it was known as “the working man’s feast.”
During the 1880s and 1890s Todd invested in real estate much of the profits yielded by his business; he owned commercial and residential land in most of the cities of the province, especially in Vancouver, and he had substantial holdings of farm land in the Fraser valley. After his death in 1899 it was reported in the press that his estate was the largest ever probated in British Columbia. LINK to his complete biography - www.biographi.ca/en/bio/todd_jacob_hunter_12E.html
Plaza Centro
A small central plaza inspired by my trip to southerern Europe this summer. The plaza is adjacent to a park entrance.
I've attempted to make a curved corner and for the best part its reasonably stable. Hopefully I can perfect it in future builds as the architecture there is excellent and totally different to what I see at home.
Cheers!
We need to put something on a hill (in future Lugpol train diorama). Well here it is.
Special thanks for Sariel for photos (sariel.pl/) and Zgredek (www.flickr.com/photos/38463026@N04/sets/) for bricks.
Full gallery will be here:
Super excited that I was not only able to get a retro style bathing suit, but guessed my size online and it actually fit perfect! I have a few others in future sessions down the road (it is summer after all!).
175113 arrives into Hereford, bang on time, working 1W60, the 11:03 Carmarthen - Manchester Piccadilly service.
Been experimenting with a copyright mark, and it may be quite a bit smaller in future.. Any feedback would be greatly appreciated!
I actually took this picture a few days ago but forgot to upload it ^^; Unfortunately, I'm not super fond of Haru so I doubt I'll ever get the purple Haru to toss in future photos but I am definitely already in love with the new Egyptian Sophie
From right to left: Wizard of Oz Lea in light gray resin, Snow Queen Miel in light blue resin, Alicce in Wonderland Lea in normal resin, Aladdin OE Cocoa in light tan resin and Pirate Lea in tan resin
Super excited that I was not only able to get a retro style bathing suit, but guessed my size online and it actually fit perfect! I have a few others in future sessions down the road (it is summer after all!).
The neon glow of the Innoventions Plazza in Future World at EPCOT Center. Please view original (full size).
BOX DATE: 2015
MANUFACTURER: Hasbro
DOLLS IN PACK: Maleficent, Mal
BODY TYPE: 2014; B5143; molded diamond panties; articulated elbows, wrists, & knees
HEAD MOLD: No date Disney "Maleficent"
PERSONAL FUN FACT: Maleficent was always one of my favorite Descendants dolls. The traditional version of Maleficent was one of the most intimidating Disney villains...at least to my younger self. I recall that my Auntie Kim had Sleeping Beauty on VHS at her house. Whenever we'd go with our parents to visit Auntie Kim and Uncle Ray, I'd almost always talk Colleen into watching Sleeping Beauty. Admittedly, I found Aurora herself to be very dull. I mostly was obsessed with the film because I liked watching the fairies fail at domestic work, and because of Maleficent. have had a fascination with Maleficent dolls of any kind, since I started collecting my plastic friends again in 2011. The Descendants line was on my radar before it was even officially released. I had seen photos from a toy fair of the dolls several months in advance. I fell in love with the dolls' ultra cartoon like faces, large heads, and modern styling. Later on when this Maleficent doll was available, I was even more excited. I decided against purchasing any of the Descendants dolls when they were in stores, since they were somewhat pricey. Back then, I was focusing my attention on Bratz, Moxie Girlz, and Monster High. So my wallet was already spread pretty thin. I figured these dolls would pop up secondhand in future years, and that's when I'd start buying them. Presently, I've had wonderful luck finding these dollies in the wild. They are often still sporting their original attire, with shoes included, and for just a few dollars each. This Maleficent turned up at the local flea market in October of 2022. She was at a regular booth--the couple we frequently buy Monster High dolls from. Most of the season they hadn't brought many things of interest, other than the three Sunshine Family dolls I'd stalked. I spotted Maleficent on top of the usual pile of dressed dollies. I couldn't believe that I had found this lady!! We checked to make sure both her hands were intact. I did have spare hands at home, but it's still a good practice to keep. Other than a slight tear on her dress, Maleficent was practically brand new. Of course she was treated to a day at the spa, alongside Royal England Barbie (who I found a few minutes later). I can't decide what my favorite feature of this doll is. She has striking horns which are molded to her head...but she also has glittery makeup (my personal weakness). For a villain, this doll sure doesn't look remotely evil. I'd invite her over for tea!
The Assumption of the Blessed Virgin, Ufford, Suffolk
Upper Ufford is a pleasant place, and known well enough in Suffolk. Pretty much an extension northwards of Woodbridge and Melton, it is a prosperous community, convenient without being suburban. Ufford Park Hotel is an enjoyable venue in to attend professional courses and conferences, and the former St Audrey's mental hospital grounds across the road are now picturesque with luxury flats and houses. And I am told that the Ufford Park golf course is good, too, for those who like that kind of thing.
But as I say, that Ufford is really just an extension of Melton. In fact, there is another Ufford. It is in the valley below, more than a mile away along narrow lanes and set in deep countryside beside the Deben, sits Lower Ufford. To reach it, you follow ways so rarely used that grass grows up the middle. You pass old Melton church, redundant since the 19th century, but still in use for occasional exhibitions and performances, and once home to the seven sacrament font that is now in the plain 19th century building up in the main village. Eventually, the lane widens, and you come into the single street of a pretty, tiny hamlet, the church tower hidden from you by old cottages and houses. In one direction, the lane to Bromeswell takes you past Lower Ufford's delicious little pub, the White Lion. A stalwart survivor among fast disappearing English country pubs, the beer still comes out of barrels and the bar is like a kitchen. I cannot think that a visit to Ufford should be undertaken without at least a pint there. And, at the other end of the street, set back in a close between cottages, sits the Assumption, its 14th century tower facing the street, a classic Suffolk moment.
The dedication was once that of hundreds of East Anglian churches, transformed to 'St Mary' by the Reformation and centuries of disuse before the 19th century revival, but revived both here and at Haughley near Stowmarket. In late medieval times, it coincided with the height of the harvest, and in those days East Anglia was Our Lady's Dowry, intensely Catholic, intimately Marian.
The Assumption was almost certainly not the original dedication of this church. There was a church here for centuries before the late middle ages, and although there are no traces of any pre-Conquest building, the apse of an early-Norman church has been discovered under the floor of the north side of the chancel. The current chancel has a late Norman doorway, although it has been substantially rebuilt since, and in any case the great glories of Ufford are all 15th century. Perhaps the most dramatic is the porch, one of Suffolk's best, covered in flushwork and intriguing carvings.
Ufford's graveyard is beautiful; wild and ancient. I wandered around for a while, spotting the curious blue crucifix to the east of the church, and reading old gravestones. One, to an early 19th century gardener at Ufford Hall, has his gardening equipment carved at the top. The church is secretive, hidden on all sides by venerable trees, difficult to photograph but lovely anyway. I stopped to look at it from the unfamiliar north-east; the Victorian schoolroom, now a vestry, juts out like a small cottage. I walked back around to the south side, where the gorgeous porch is like a small palace against the body of the church. I knew the church would be open, because it is every day. And then, through the porch, and down into the north aisle, into the cool, dim, creamy light.
On the afternoon of Wednesday, 21st August 1644, Ufford had a famous visitor, a man who entered the church in exactly the same way, a man who recorded the events of that day in his journal. There were several differences between his visit and the one that I was making, one of them crucial; he found the church locked. He was the Commissioner to the Earl of Manchester for the Imposition in the Eastern Association of the Parliamentary Ordinance for the Demolishing of Monuments of Idolatry, and his name was William Dowsing.
Dowsing was a kind of 17th century political commissar, travelling the eastern counties and enforcing government legislation. He was checking that local officials had carried out what they were meant to do, and that they believed in what they were doing. In effect, he was getting them to work and think in the new ways that the central government required. It wasn't really a witch hunt, although God knows such things did exist in abundance at that time. It was more as if an arm of the state extended and worked its fingers into even the tiniest and most remote parishes. Anyone working in the public sector in Britain in the early years of the 21st century will have come across people like Dowsing.
As a part of his job, Dowsing was an iconoclast, charged with ensuring that idolatrous images were excised from the churches of the region. He is a man blamed for a lot. In fact, virtually all the Catholic imagery in English churches had been destroyed by the Anglican reformers almost a hundred years before Dowsing came along. All that survived was that which was difficult to destroy - angels in the roofs, gable crosses, and the like - and that which was inconvenient to replace - primarily, stained glass. Otherwise, in the late 1540s the statues had been burnt, the bench ends smashed, the wallpaintings whitewashed, the roods hauled down and the fonts plastered over. I have lost count of the times I have been told by churchwardens, or read in church guides, that the hatchet job on the bench ends or the font in their church was the work of 'William Dowsing' or 'Oliver Cromwell'. In fact, this destruction was from a century earlier than William Dowsing. Sometimes, I have even been told this at churches which Dowsing demonstrably did not visit.
Dowsing's main targets included stained glass, which the pragmatic Anglican reformers had left alone because of the expense of replacing it, and crosses and angels, and chancel steps. We can deduce from Dowsing's journal which medieval imagery had survived for him to see, and that which had already been hidden - not, I hasten to add, because people wanted to 'save' Catholic images, but rather because this was an expedient way of getting rid of them. So, for example, Dowsing visited three churches during his progress through Suffolk which today have seven sacrament fonts, but Dowsing does not mention a single one of them in his journal; they had all been plastered over long ago.
In fact, Dowsing was not worried so much about medieval survivals. What concerned him more was overturning the reforms put in place by the ritualist Archbishop Laud in the 1630s. Laud had tried to restore the sacramental nature of the Church, primarily by putting the altar back in the chancel and building it up on raised steps. Laud had since been beheaded thanks to puritan popular opinion, but the evidence of his wickedness still filled the parish churches of England. The single order that Dowsing gave during his progress more than any other was that chancel steps should be levelled.
The 21st of August was a hot day, and Dowsing had much work to do. He had already visited the two Trimley churches, as well as Brightwell and Levington, that morning, and he had plans to reach Baylham on the other side of Ipswich before nightfall. Much to his frustration, he was delayed at Ufford for two hours by a dispute between the church wardens over whether or not to allow him access.
The thing was, he had been here before. Eight months earlier, as part of a routine visit, he had destroyed some Catholic images that were in stained glass, and prayer clauses in brass inscriptions, but had trusted the churchwardens to deal with a multitude of other sins, images that were beyond his reach without a ladder, or which would be too time-consuming. This was common practice - after all, the churchwardens of Suffolk were generally equally as puritan as Dowsing. It was assumed that people in such a position were supporters of the New Puritan project, especially in East Anglia. Dowsing rarely revisited churches. But, for some reason, he felt he had to come back here to make sure that his orders had been carried out.
Why was this? In retrospect, we can see that Ufford was one of less than half a dozen churches where the churchwardens were uncooperative. Elsewhere, at hundreds of other churches, the wardens welcomed Dowsing with open arms. And Dowsing only visited churches in the first place if it was thought there might be a problem, parishes with notorious 'scandalous ministers' - which is to say, theological liberals. Richard Lovekin, the Rector of Ufford, had been turned out of his living the previous year, although he survived to return when the Church of England was restored in 1660. But that was in the future. Something about his January visit told Dowsing that he needed to come back to Ufford.
Standing in the nave of the Assumption today, you can still see something that Dowsing saw, something which he must have seen in January, but which he doesn't mention until his second visit, in the entry in his journal for August 21st, which appears to be written in a passion. This is Ufford's most famous treasure, the great 15th century font cover.
It rises, six metres high, magnificent and stately, into the clerestory, enormous in its scale and presence. In all England, only the font cover at Southwold is taller. The cover is telescopic, and crocketting and arcading dances around it like waterfalls and forests. There are tiny niches, filled today with 19th century statues. At the top is a gilt pelican, plucking its breast.
Dowsing describes the font cover as glorious... like a pope's triple crown... but this is just anti-Catholic innuendo. The word glorious in the 17th century meant about the same as the word 'pretentious' means to us now - Dowsing was scoffing. But there was no reason for him to be offended by it. The Anglicans had destroyed all the statues in the niches a century before, and all that remained was the pelican at the top, pecking its breast to feed its chicks. Dowsing would have known that this was a Catholic image of the Sacrifice of the Mass, and would have disapproved. But he did not order the font cover to be destroyed. After all, the rest of the cover was harmless enough, apart from being a waste of good firewood, and the awkwardness of the Ufford churchwardens seems to have put him off following through. He never went back.
Certainly, there can have been no theological reason for the churchwardens to protect their font cover. I like to think that they looked after it simply because they knew it to be beautiful, and that they also knew it had been constructed by ordinary workmen of their parish two hundred years before, under the direction of some European master designer. They protected it because of local pride, and amen to that. The contemporary font beneath is of a type more familiar in Norfolk than Suffolk, with quatrefoils alternating with shields, and heads beneath the bowl.
While the font cover is extraordinary, and of national importance, it is one of just several medieval survivals in the nave of the Assumption. All around it are 15th century benches, with superbly characterful and imaginative images on their ends. The best is the bench with St Margaret and St Catherine on it. This was recently on display at the Victoria and Albert Museum as part of the Gothic exhibition. Other bench end figures include a long haired, haloed woman seated on a throne, which may well be a representation of the Mother of God Enthroned, and another which may be the Coronation of the Queen of Heaven. There is also a praying woman in a butterfly headdress, once one of a pair, and a man wearing what appears to be a bowler hat, although I expect it is a helmet of some kind. His beard is magnificent. There are also a number of finely carved animals.
High up in the chancel arch is an unusual survival, the crocketted rood beam that once supported the crucifix, flanked by the grieving Mary and John, with perhaps a tympanum behind depicting the last judgement. These are now all gone, of course, as is the rood loft that once stood in front of the beam and allowed access to it. But below, the dado of the screen survives, with twelve panels. Figures survive on the south side. They have not worn well. They are six female Saints: St Agnes, St Cecilia, St Agatha, St Faith, St Bridget and, uniquely in England, St Florence. Curiously, the head of this last has been, in recent years, surrounded by stars, in imitation of the later Our Lady of the Immaculate Conception. Presumably this was done in a fit of Anglo-catholic enthusiasm about a century ago.
The arrangement is similar to the south side of the screen at Westhall, and it may even be that the artist was the same. While there is no liturgical reason for having the female Saints on one side and, presumably, male Saints on the other, a similar arrangement exists on several Norfolk screens in the Dereham area.
Much of the character of the church today comes from it embracing, in the early years of the 20th century, Anglo-catholicism in full flood. As at Great Ryburgh in Norfolk, patronage ensured that this work was carried out to the very highest specification under the eye of the young Ninian Comper. Comper is an enthusiast's enthusiast, but I think he is at his best on a small scale like here and Ryburgh. His is the extraordinary war memorial window in the south aisle chapel, dedicated to St Leonard. It depicts Christ carrying his cross on the via dolorosa, but he is aided by a soldier in WWI uniform and, behind him, a sailor. The use of blues is very striking, as is the grain on the wood of the cross which, incidentally, can also be seen to the same effect on Comper's reredos at Ryburgh.
Comper's other major window here is on the north side of the nave. This is a depiction of the Annunciation, although it is the figures above which are most extraordinary. They are two of the Ancient Greek sibyls, Erythrea and Cumana, who are associated with the foretelling of Christ. At the top is a stunning Holy Trinity in the East Anglian style. There are angels at the bottom, and all in all this window shows Comper at the height of his powers.
Stepping into the chancel, there is older glass - or, at least, what at first sight appears to be. Certainly, there are some curious roundels which are probably continental 17th century work, ironically from about the same time that Dowsing was here. They were probably acquired by collectors in the 19th century, and installed here by Victorians. The image of a woman seated among goats is curious, as though she might represent the season of spring or be an allegory of fertility, but she is usually identified as St Agnes. It is a pity this roundel has been spoiled by dripping cement or plaster. Another roundel depicts St Sebastian shot with arrows, and a third St Anthony praying to a cross in the desert. However, the images in 'medieval' glass in the east window are entirely modern, though done so well you might not know. A clue, of course, is that the main figures, St Mary Salome with the infants St James and St John on the left, and St Anne with the infant Virgin on the right, are wholly un-East Anglian in style. In fact, they are 19th century copies by Clayton & Bell of images at All Souls College, Oxford, installed here in the 1970s. I also think that the images of heads below may be modern, but the angel below St Anne is 15th century, and obviously East Anglian, as is St Stephen to the north.
High above, the ancient roofs with their sacred monograms are the ones that Dowsing saw, the ones that the 15th century builders gilt and painted to be beautiful to the glory of God - and, of course, to the glory of their patrons. Rich patronage survived the Reformation, and at the west end of the south aisle is the massive memorial to Sir Henry Wood, who died in 1671, eleven years after the end of the Commonwealth. It is monumental, the wreathed ox heads a severely classical motif. Wood, Mortlock tells us, was Treasurer to the Household of Queen Henrietta Maria.
There is so much to see in this wonderful church that, even visiting time and time again, there is always something new to see, or something old to see in a new way. It is, above all, a beautiful space, and although it no longer maintains its high Anglo-catholic worship tradition, it is is still kept in high liturgical style. It is at once a beautiful art object and a hallowed space, an organic touchstone, precious and powerful.
Not the best photo in the world but at least I got one of these quick little fellows in flight. I will have to crank the SS up a bit in future!!
We spent our Xmas vacation in Hawaii Oahu for two weeks. One week we stayed in Waikiki and one week we stayed in Koolina because Raymond told me this is the best place to see sunset. Raymond absolutely right, we all fell in love with this place, especially the two natural lagoons.
Raymond, thank you for the hospitality you gave me, and I hope that I may be able to return your kindness in future.
Happy Year 2014!
On this planet we are not alone, spiecies have proceeded us and might in future...and now that we are the masters of this planet, our decisions is affecting any other living being on this sphere...
It is sad to know that, despite our techonological advances, which might preserve lif on this planet, we are getting apart from nature -at least how the trend of life is making each and every individual to be more or less self-centered rather than sharing and enjoying what is surrounding us from living beings....you are not alone!
“SATURN APOLLO 501 IN HIGH BAY 1, WITH WORK PLATFORMS RETRACTED. VAB HIGH BAY 1.
5-24-67”
Note access arm No. 8 “Service Module (inflight)” directly behind the CSM. Access arm No. 9 “Command Module (preflight)” is to the far right. Speaking of the CSM, note also the lack of RCS thrusters on the SM. Kind of clue as to vehicle identification.
And, unless something else surfaces, maybe on the verso of a “S-67-XXXXX” version of this photo - if such exists - the following lame, I’m sure contemporary pablum is apparently what’s meant to pass as the official description/caption:
“This photograph depicts the Saturn V vehicle (SA-501) for the Apollo 4 mission in the Vehicle Assembly Building (VAB) at the Kennedy Space Center (KSC). After the completion of the assembly operation, the work platform was retracted and the vehicle was readied to rollout from the VAB to the launch pad. The Apollo 4 mission was the first launch of the Saturn V launch vehicle. Objectives of the unmanned Apollo 4 test flight were to obtain flight information on launch vehicle and spacecraft structural integrity and compatibility, flight loads, stage separation, and subsystems operation including testing of restart of the S-IVB stage, and to evaluate the Apollo command module heat shield. The Apollo 4 was launched on November 9, 1967 from KSC.”
Surprisingly, the above, with a bullshit, probably arbitrarily assigned “NASA ID” of 6754387 is actually available at:
images.nasa.gov/details-6754387
Unfortunately, as with many others, the description has been propagated everywhere. While I’ve read MUCH worse, it’s merely a copy/paste from some Apollo 4 document, which doesn’t address the context of the photograph…that is, what’s actually going on…the REASON the photograph was taken.
With that, the recognition/correct identification of the content of this photograph, along with the date, hence its pertinence to the problematic history of the SA-501 vehicle, has been…take your pick: lost, overlooked, unrecognized, omitted…something unacceptable.
For starters, the NASA photo ninjas, especially at the time of the photo’s processing, i.e., 1967, should’ve recognized that the CSM atop the vehicle was NOT the flight CSM (CSM-017). It ALSO should’ve been easily/readily identified as M-11, the Flight Verification Vehicle (FVV), it having been photographed a bazillion times during 1966 as part of SA-500F photo documentation.
As if that weren’t enough, within the multiple regurgitations of the trials & tribulations of making Apollo 4 happen, there’s not a mention of M-11, other than within the following, which although incomplete, with its own errors, at least references it…ONCE:
“The third stage (S-IVB) was the first major component of Apollo 4 to be delivered at KSC. It arrived from Sacramento aboard the Guppy aircraft on 14 August 1966 and went immediately into a low bay of the assembly building for inspection and checkout. The following week the spacer and instrument unit arrived. On 12 September, as Peter Conrad and Richard Gordon prepared to blast off in Gemini 11, the barge Poseidon sailed into the Banana River with the first stage. Boeing gave it a lengthy checkout in the transfer aisle of the high bay before erecting the booster on 27 October. During the following week, technicians stacked the remaining launch vehicle stages, using the spool for the absent S-II. There were a few problems - the checkout of the swing arms took an extra two days and a cooling unit for the instrument unit sprang a leak - but the launch team, still counting on the mid-November delivery date for the S-II, hoped to roll the complete vehicle out to pad A by 13 January 1967.
By late November the Apollo Program Office had moved the S-II's arrival back to January, and the launch back to April. Since spacecraft 017 would not arrive for another three weeks, KSC erected the facilities verification model of Apollo on 28 November.
[The first linked black & white photograph by Cliff Steenhoff below, depicts such.]
This allowed North American to check out some of its spacecraft support equipment. The first week in December the memory core in a digital events evaluator failed after intermittent troubles; cracked solder joints were blamed. A hurried repair put the computer back on line.
The command-service module arrived at KSC on Christmas Eve and was mated to the launch vehicle on 12 January 1967. That tardy prima donna, the S-II stage, finally appeared on 21 January. Tank inspection, insulation, and engine work were in progress by the 23rd. Test crews found damaged connectors on three recirculation pumps and set about investigating the extent of the rework that would be necessary. While inspecting the liquid hydrogen tank on the second stage, the North American team found 22 cracked gussets. These triangular metal braces, used to support the horizontal ribs of the stage framework, had to be replaced. Plans to move the second stage into a low bay checkout cell on the 29th were temporarily set aside because of a late shipment of the aft interstage (the cylindrical aluminum structure that formed the structural interface between the first and second stages). The interstage arrived on 31 January, and by the end of the next day the stage was in a low bay cell with work platforms around it.
Despite the delay with the S-II stage, KSC officials expected to meet the new launch date in May. The fire on 27 January placed all schedules in question. Although Apollo 4 was an unmanned mission, NASA officials wanted to give command-module 017 a close examination. On 14 February, a week before the S-II could be inserted into a fully assembled vehicle, the spacecraft was removed from the stack and taken to the operations and checkout building. When inspection disclosed a number of wiring errors, KSC's Operations Office cancelled the restacking of the spacecraft. By 1 March electrical engineers had discovered so many wiring discrepancies that the test team stopped their repair work, pending a thorough investigation of all spacecraft wiring. Within two weeks the North American and NASA quality control teams recorded 1,407 discrepancies. While North American repaired about half of these on the spot, modifications, repair work, and validations continued into June. During the break technicians performed pressure tests on service module systems at pad 16. It would be mid-June, with the wiring modifications for the command module finally completed, before North American could remate the spacecraft and take it back to the assembly building.
As the extent of the wiring problems was not immediately recognized, the launch vehicle team forged ahead to recoup the time lost on the S-II stage. In mid-February Boeing's airframe handling and ordnance group removed the instrument unit and spacer from the 501 stack and on the 23rd erected the S-II. The operation involved incredibly close tolerances. To qualify crane handlers, Stanley Smith, Bendix senior engineer of the crane and hoist group, stated, "We give them a technical examination and then check their reflexes and response to commands in training sessions." During a mating, an operator and an electrician boarded the crane and another man helped guide movements from the floor by communicating with the operator via a walkie-talkie. Smith set a high goal for his team: "We strive to train our men to the point where they could conceivably lower the crane hook on top of an egg without breaking the shell."
After a stage was properly aligned on the Saturn stack, a crew of one engineer, two quality control inspectors, one chief mechanic, and eight assistants took eight hours to complete the mating. Three 30-centimeter pins on the second stage fitted into brackets located 120 degrees apart on the periphery of the first stage. Then the mechanics inserted 216 one-centimeter, high-strength fasteners into matching holes around the perimeter where the two stages joined. The team torqued the fasteners in a staggered sequence to secure the bolts evenly and ensure a uniform distribution of stress. The mating of the second and third stages was conducted in much the same manner. The 501 was now set up except for the missing CSM.
[This is where something about the FVV (M-11) being reincorporated into the stack should’ve been referenced.]
The lengthy delays with the flight hardware aided the Site Activation Board in its efforts to get LC-39 ready for its first launch. The board's first flow [see chapter 15-1] included firing room 1, mobile launcher 1, high bay 1, and the other facilities required for the support of Apollo 4 - 1,280 activities altogether. During the first quarter of 1967, PERT charts showed less than 1% of these activities behind schedule. The decision in mid-April to modify the LOX system on launcher 1 and pad A put five weeks of negative slack into the site activation schedule. The modifications were made necessary by excessive pressure in the LOX system. KSC engineers added an automatic bleed system, relief valve supports, and a block valve that prevented purging through the drain line. As continued vehicle problems further delayed the rollout, the five weeks of negative slack disappeared.
On 24 May the S-II stage was in trouble again. NASA announced it would be dismantled for inspection, consequent on the discovery of hairline cracks in the propellant tank weld seams on another S-II at the factory in California.
[The photograph is dated 5-24-67. If correct, then the image was taken as part of documenting preparations for destacking M-11 & the S-IVB in order to remove the S-II stage.]
Additionally, thanks to the remarkable “CAPCOM ESPACE” website:
“For Apollo 4, the M11 was placed on launcher 501 on November 28, 1966 and removed at the end of 1966 following delays in stage S2. It will be put back in place on April 6, 1967 and removed on May 26.”]
Above, along with much more good stuff, at:
www.capcomespace.net/dossiers/espace_US/apollo/vaisseaux/...
So, somewhere out there, there’s some documentation from which the above was gleaned. I probably don’t have it & certainly didn’t find it online.]
The additional checks were not expected to delay the flight of 501 "more than a week or so." By mid-June the inspection, which included extensive x-ray and dye penetrant tests, was completed and the stage returned to the stack. On 20 June, the command-service module was mechanically mated to the Saturn V, and 501 was - at last - a fully assembled space vehicle. A revised schedule on 21 July set rollout for mid-August. On 26 August 1967, the big rocket emerged from the high bay slightly more than a year after its first components had arrived at KSC, and a good six months after its originally scheduled launch date. It had been a year of delay and frustration, and the end was not yet.”
The above, other than the inserted (bracketed) astute comments, observations & additional useful links, at/from:
www.hq.nasa.gov/office/pao/History/SP-4204/ch19-3.html
Inexcusable, incompetent, confounding at least, considering the importance/significance of this vehicle. But then again, for an organization that seems to have “officially/formally” misidentified the Command Module on display at Expo ’67 – to this day – the oversight, ignorance & tacit mis/non-identification of a lowly FVV is both literally & figuratively a no-brainer. The buffoonery continues. At least this shit is so far back in the rearview mirror that no one remembers, those that did are probably dead, and no one now cares, or will in the future. No harm, no foul, all good. 👍
More Detailed Pictures on Imgur: imgur.com/a/FT5L6l6
A DC MOC from Ben?!?! Whattt!!! ... This isn't Marvel!
Yeah man DC is rad, and so was the Aquaman movie! After buying the set based off of the movie, I just had to make a vig with those figs. Really happy with this one. Would love to play with 'underwater stuff' again in future!
Also I would've posted detailed pictures on MOCpages or Brickshelf, but both site aren't working (I can upload to MOCpages but the images become dead links, and Brickshelf I can't login or even create an account) ... Anyone know what's up there?
All in camera - single exposure. Please see ""Let's Glow More Sunflowers!" for images of the kit used.
This is the second in a series of light stenciled propaganda posters I'm attempting with the much appreciated help of the Hooded Accomplice.
For light stenciling, you build a foil box, put an image on the front of it, and fire a flash through it from behind. The flash lights the image and "stamps" it onto your sensor/film. Then you move the box, and let the rest of the scene burn in. If you're interested, I'd recommend you check out tdub303's excellent tutorial piece here.
I put some quick thoughts down in the first of the series (linked above) as to why on earth you would choose to do it this way, in camera, rather than using Photoshop. Certainly it takes a lot of time and demands you make a lot of cumbersome kit to burden yourself with. However, the challenges it throws up are worth confronting. This is how you learn about light and cameras.
Hope everyone is having a great week!
Using an ESP32 board to push images to a small TFT display. Will hopefully be able to make use of these in future buildings.
Sony A7RII +Techart Techart Pro M/E Autofocus Adapter* + Leica Summilux-M 50mm f/1.4 ASPH.
Handheld. Edited in Lightroom CC + VSCO.
From Hong Kong.
* Somehow the Techart Pro Adaptor will register as DT 40mm F2.8 SAM in the Sony A7RII...not sure if that will be fixed in future firmware release.
Press "L" to view large scale.
Again I was surprised by the colours of the background. I always look trough the subject to the background when taking pictures. I think that it often creates the atmosphere of a picture. Simple changes by position, a cloud, shadow etc. often shows a great different in a picture of the same subject. I never create a background or change colours til now by using software. Maybe I'll try in future,
Een heel goed week end.
Have a great week end.
Хорошего конца недели.
آخر هفته خوب است.
ونهاية الاسبوع جيدة.
Pokot village.
The Pokot people are categorized under the larger Kalenjin tribes grouping of Kenyan Nilotic speakers because they have oral traditions of a similar origin. They speak the Pokot language. The Pokot people live in the Baringo and Western Pokot districts of Kenya and also in the Eastern Karamoja region of Uganda. The Pokots are dived into two main sub-groups depending of their location and way of life. The two groups are the Hill Pokot who practice both farming and pastoralism, and live in the rainy highlands in the west and in the central south. The second group is made up of the Plains Pokot who living in dry and infertile plains, herd cows, goats and sheep.
As a result of their nomadic lifestyle, adopted by most of the Pokot, they have interacted with different peoples in their history and therefore incorporated social customs of neighbors into their life. The Turkana and the Karamojong of Uganda, who they neighbor, appear to have had the most influence on the Pokot. Those who are cultivators mainly grow corn/maize. Nevertheless, whether a pastoralist or a farmer, wealth among the Pokot is measured by the number of cattle one has. The other major uses of cows are in bride price and barter trade. As long as a Pokot man has enough wealth in terms of cows to offer, marrying more than one wife is allowed.
Dairy products like milk are an important part of the diet of the Pokot. Porridge made from wild fruits boiled with a mixture of milk and blood, a repast rich in nutrients and iron is the staple of the Pokot diet. Using a special arrow, it's shot into the neck of a cow to drain blood without permanently causing harm to the animal.
The Tororot being the utmost god according to the Pokot, prayers and sacrifices are made to him during ethnic festivals and dances that are organized by their elders. Also, the Pokot have diviners who are in charge for maintaining the spiritual balance within their society. Being superstitious and believing in sorcery and sometimes calling on various forms of shielding lucky charms to ward off the ill will of any sorcerers is a part of their tradition. They also worship other deities like the sun, moon and believe in the spirit of death.
Governing within the Pokot community, is through a number of age-sets and association with any particular set is be determined by the age during which a Pokot goes through their initiation into that set group or society. It is typically between the ages of fifteen and twenty for the men while, it is around twelve, for the women. Matrimonial binds for the youngsters are allowed, once the initiation has been accomplished. As well, they begin taking part in the local economic functions. The bonds formed within the initiation groups, are close and are functional in future political ties as they progress through the positions in the tribal organization. At old age, they get a certain degree of status and the esteem that goes with it. Presiding over important tribal decisions, festivals and religious celebrations are the duties among others that elders are in charge of.
The Pokot are quite proud of their culture are bound to hold on to it in the future. Generally, Pokot women wear colorful necklaces and beaded headgears, brass jewelry and big loop type earrings whereas men wear just a few wrap garments and cowhide capes and shirts. They use beaded skirts to distinguish those females who have been initiated from those who haven't. Pokot warriors wear red clay on their hair, special headgears of feathers. Dances are an important aspect of their culture especially during social-cultural events.
**View On Black* (Please Press "L')
愛散發的溫柔在此刻用心感受
www.youtube.com/watch?v=_QtkNKHD2bw&list=FLpt1qpOq9s5...
愛有夢才快樂
就算未來的路都不同
你在我心中到永久
When there's dream in love, there's happiness,
Even if we go our separate ways in future
You wil be in my heart forever
© All rights reserved Anna Kwa. Please do not use this image on websites, blogs or any other media without my explicit written permission.
... this is my 1000th Upload on Flickr ... It's been a fascinating journey of capturing frames. Special thanks to all who have been with me in this short endeavour in photography ...
hope you'll be with me in future and inspire with your encouraging comments ..!
It is a long-distance lovely migrant bird and visit Taiwan.
Carry on my gear(15.5 kg).
About 1 km flat road, after that a vertical climbing a total of 2.4 km.
I suspect, the feet tell me and may have to strike for three days.
Need to go massage.. Lol..
Of cause, hard job will feed back,
have other good one, post after few days..
Thank you for the comment and Award with invite..
Have a nice day&night..
We know nothing of what will happen in future, but by the analogy of past experience.
~~ By from Abraham Li. ~~
Warm Kind regards
Aber
en.wikipedia.org/wiki/Chestnut_Bunting
Yehliu Geopark of Taiwan and welcome.
November 2025
Curator - An AI Photography Critique system
Caption: a city street with a bus and a car
Style: Street
Interestingness: 6.27/10 (★★★☆☆)
Critique: Overall, this image captures a typical street scene in an urban environment, reflecting the essence of city life with its mix of architectural elements and human activity. The main visual strength lies in the contrast between light and shadow, which adds depth to the photograph and highlights certain aspects while leaving others in darkness.
As for secondary observations, there seems to be room for improvement regarding composition; the image feels somewhat unbalanced due to an uneven distribution of subjects across the frame. Additionally, although it's a street photography style piece, one could argue that capturing more decisive moments or interactions between people would elevate its storytelling potential and potentially increase the score.
One actionable improvement is considering adjusting the framing slightly so as not to cut off parts of the buildings on either side, allowing for better visual flow within the image. Overall, while it's a snapshot with clear intentions, refining these elements could enhance both technical execution and narrative impact in future works.
Camera: Ricoh, GR III, lens:GR LENS 18.3mm F2.8, 18mm, f/5.6, ISO200
This was really amazing! It's a Blythe head on a Monster High body! She was so lovely!! I hope someone does more of these in future. :D
This is a product shot with extreme micro technique. Kenco extension tube having used.
The color are all natural. It is my intension to use the old watch for this shot.
You might wonder why I put this title!!
This watch is actually over 28 years now. it was given by my late father when I returned from Swansea; Wales; UK.
I have use this all the time except few occasion I use other branded watch for the VIP function.
In the old Chinese Saying:
The $ value is not as valuable then the thoughts!!
Especially, now My Dad's is already gone, whenever I see the watch, I think about him. & I missed him. Although when I was 12, he beaten me up until I wounded, & Again in 1990 after I my successful initialization of "Creating The New Excellence Philips Corporate Culture", then Philips disbanded my division in Telecom & Data System. When I return to S.E.A.. The 2nd Brother's in the family have set things up for both parents to dis-owned me.
I experience worst family wealth; money; politics & struggle in my life. The reason for me to walk away is because I just don't want to get involve.( It is the same in my careers with those multi-natinational corp as well.) In 1990 Nov, I attended Comdex & I wrote back to both the 38 points of the family trouble & my visions of what have become for the family in future. Then my mom's burn the letter upon receiving.
Before, both passed away, they looks back & think back for what have happening & the expel of me from the family, they are very much regret, especially their near death experience whereby the Yamas' (Emperors' of Hells) told them what is truth. However, it is too late.
Well, whatever happening, I still pray for them to rebirth in the higher plane. As the Buddha said Birth is suffering, all beings are suffering except become the perfect one; the excel one; the enlighten one -- that is become the Buddha oneself.
At the month of "Ching Ming" - Month of remembrance; let's pray & transfer merits to all our 3 births parents' ( That is Past Present & Future!!)
Satu; Satu; Satu...
Peace; Peace; Peace.....................
I know the new all singing and dancing flickr is with us; but should you want to see it large then click
Cwm Idwal shot earlier in the year. I forget what grad i used for this shot, i suspect it was a 1.2 lee soft grad on a 70-200 lens.
Also, my pro account runs out today, i doubt whether i will renew it; whilst i enjoy the community of flickr i dont like what flickr has become as a corporate body. In future i will be paying for a smugmug account. I will still load on here but the archives will probably be lost.
Day 53/365
"Equilibrium...The Art of Glasses"
This is my second art of equilibrium collection.
hobefully in future I will take it to wild level ;)
Abut this photo: this photo is colored!! its not black and white, its my first time that I beat the camera sensor in term of matching colors since the background is brown sheet and in the right is blue sheet and in the left purple sheet.
Strobist Info: 2x 580EX II one from the left and one from the right and both are in TTL -1 mode pointed to the background from behind the sided sheets.
Flash triggered via Pocket wizard MiniTT1 and FlexTT5.
Rather than using a water bottle to make the drop I thought I'd use the tap this time. It made focusing a little bit easier but brought with it other problems such as poor light, difficulty placing the background, shadows...
I'll stick to a bottle in future.
Faux tilt shift of a river in the Dublin mountains. The original shot looked enough like a model to warrant me adding the effect (i like tilt shift in moderation).
The oversaturation is part of the effect :)
Best viewed Large On Black.
Please, if you're giving this photo a low rating tell me why. That way I can improve in future.
For more photos follow me on twitter, on my blog or on shuttrr.
This is the 112th Image in my 365 challenge.
This post is to get an idea of who is currently active in the group.
I tagged members I know to have posted recently. A few members I was not able to tag. If anyone wishes to be removed from the photo ask me and I will remove the tag. If you want added or know someone that should be added, let me know. Also if for some reason you don't like to be tagged, let me know for future reference.
We thought a photo post would be easier than adding a topic in the discussions section. Andhe has made an 'Active Characters Thread" which can be found here:
www.flickr.com/groups/llh/discuss/72157684748074444/
This will also help for collaborating and to get an idea who wants tagged in future posts. We know a lot of you have other projects, but if you have been active or plan to be more active in the group, comment below. As always no matter how new you are to the group, feel free to chime in.
I'm sure I'm leaving out some info, but the main goal is just to get an idea of who's active.
I'll edit this post as needed.
New 3D-printed rods for the 60 Class Garratt and my first attempt at designing and printing Walschaerts valve gear.
I finally found some time to make 3D printed rods for the Garratt. I have made them 2mm wide, which substantially reduces the width of the valve gear. While the original rods were more ‘Lego’, I think the thinner 3D rods look a lot better.
I’m still working out the best settings to use on the 3D printer, and can hopefully improve the finish in future, but I think these are good enough to be going on with.
The loco ran well on an initial test, but if there are issues, they will show up when it runs at the next show in August.
I only discovered this company called Economy Waste a few months ago when I was out videoing some Central Coast residential trucks. I was stopped at a set of lights in West Gosford and next thing a beast 8x4 Kenworth with an open top bin on the back goes past me, surprisingly being a dino instead of the hook lift I first expected. While having a quick feed at KFC, I sussed out the company on Google, learning their yard was just up the road :D In the blink of an eye I was having a brief chat with the boss and got a little look at a couple of other trucks run by the business. The first fleet member to catch my eye was the pictured one with the bail hook sticking out of the frame rails, belonging to an awesome 1988 Kenworth L710. The next truck over is just a bare chassis Hino which I didn’t query, and behind that is a monster Kenworth marrel... I really want to check this fleet out more in future! Bugger I didn’t get a good photo (do a Google search) of the first Kenworth I spotted, but a rego check tells me it’s a 2002 K104 model, something I class as a damn fucking real truck after hearing the exhaust grumble. Economy Waste appears to have a decent local customer base on the Central Coast, but I also get the impression they subcontract to the bigger companies in the area. As per the mudguard, I believe the name “Calleija” also has some ties to the waste industry of the old days.
The 1989–90 Whitbread Round the World Race was run from Southampton to Southampton in 1989–90. It was run with several classes of yacht.
Steinlager 2 skippered by Peter Blake won the race easily. For the first time since 1981–82 (when the race comprised just four legs), the victor won every leg (albeit closely chased by both Grant Dalton's Fisher & Paykel NZ and Pierre Fehlmann's Merit entries). The vast difference in speed and capability of the many different boats involved in the 1989 to 1990 race lead to the creation of a committee to examine the commission of a Whitbread class boat for use in future races. Many of the Maxi yachts in this year's race were nearly twice the size (LOA) of the smallest, and carried well over twice the sail area. The net result of this was that many of the smaller boats finished the longer legs more than ten days after the leg winner. In the overall results, the last finisher was some 52 days behind Blake's Steinlager 2 128-day aggregate time. In addition, the cost of the big yachts was becoming too expensive to fund - even for the well sponsored teams like Steinlager, Rothmans and Merit. Eventually, the new class would be called the Whitbread 60.
The race featured the first all-woman crew on Tracy Edwards' Maiden. Although in a much smaller boat than many of their male counterparts the women fared well—claiming two leg victories in Division D.[1] Edwards was named yachtsman of the year and appointed MBE. Recently a documentary has been made about the team's participation in the race.
Central Auckland Statistical Area, Auckland, New Zealand
I took myself a photo of this WSN/SITA/Suez truck ejecting a load at Pioneer Waste Management in Taren Point, being the average 5t of bulk waste taken away from Kogarah. Worth noting is that this is a Heil Europe machine, obvious telltale being the control console - funny thing is that the lifter was operated by a valve lever instead of buttons like you’d expect! Had a lot of problems with the packer on this, lots of manual operation was required mainly during the second half of the cycle, kept seizing up in auto. Something I’ve gotta mention is how awesome this truck sounded at every point, even just the sharp kick of revs when dis/engaging the tailgate locks... especially epic doing the Pacific Square dock in Maroubra but. This truck did do Randwick for a short time when I transferred across, and it was mad fun to use, might’ve had some hardware issues and bent lifter teeth, but it worked quick and went tough. Absolutely devo I never managed to take a video and probably won’t in future.
Sat down for 3 days doing this a few weeks back while I was sick. Keep an eye out for this in future.
This is a first bloom of a mericlone growing in a 5-inch plastic pot. The dark red flowers measure 4 inches across. It is expected that the flowers will be larger in future blooms. The flowers have bright yellow veins at the mid lobe of the lip.
During a search of places to potentially visit, I came across an image taken from around here. The potential was clear so thought it'd be worth a shot. We got here and this was the view we were treated to. Definitely a place to return to in future!
Ebony SV45TE
Schneider 110mm XL
Fuji Provia 100F
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.
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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.
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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].
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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].
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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.
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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).
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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].
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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.
Visiting St Machars Cathedral today 12/5/2018, I noticed this beautiful Blossom Tree dominating the centre of the grave yard in amongst graves dating back hundreds of years , made me think life still goes on, no matter who has passed away, rank, position, fame , recognition, money etc does not matter, when its our time to fall asleep , the world will still turn and life will go on, forever.
Resurrection
Resurrection is the concept of coming back to life after death. In a number of ancient religions, a dying-and-rising god is a deity which dies and resurrects. The death and resurrection of Jesus, an example of resurrection, is the central focus of Christianity.
As a religious concept, it is used in two distinct respects: a belief in the resurrection of individual souls that is current and ongoing (Christian idealism, realized eschatology), or else a belief in a singular resurrection of the dead at the end of the world. The resurrection of the dead is a standard eschatological belief in the Abrahamic religions.
Some believe the soul is the actual vehicle by which people are resurrected.
Christian theological debate ensues with regard to what kind of resurrection is factual – either a spiritual resurrection with a spirit body into Heaven, or a material resurrection with a restored human body. While most Christians believe Jesus' resurrection from the dead and ascension to Heaven was in a material body, a very small minority believe it was spiritual.
There are documented rare cases of the return to life of the clinically dead which are classified scientifically as examples of the Lazarus syndrome, a term originating from the Biblical story of the Resurrection of Lazarus.
Etymology
Resurrection, from the Latin noun resurrectio -onis, from the verb rego, "to make straight, rule" + preposition sub, "under", altered to subrigo and contracted to surgo, surrexi, surrectum + preposition re-, "again", thus literally "a straightening from under again".
Religion
Ancient religions in the Near East
See also: Dying-and-rising god
The concept of resurrection is found in the writings of some ancient non-Abrahamic religions in the Middle East. A few extant Egyptian and Canaanite writings allude to dying and rising gods such as Osiris and Baal. Sir James Frazer in his book The Golden Bough relates to these dying and rising gods, but many of his examples, according to various scholars, distort the sources. Taking a more positive position, Tryggve Mettinger argues in his recent book that the category of rise and return to life is significant for the following deities: Ugaritic Baal, Melqart, Adonis, Eshmun, Osiris and Dumuzi.
Ancient Greek religion
In ancient Greek religion a number of men and women were made physically immortal as they were resurrected from the dead. Asclepius was killed by Zeus, only to be resurrected and transformed into a major deity. Achilles, after being killed, was snatched from his funeral pyre by his divine mother Thetis and resurrected, brought to an immortal existence in either Leuce, Elysian plains or the Islands of the Blessed. Memnon, who was killed by Achilles, seems to have received a similar fate. Alcmene, Castor, Heracles, and Melicertes, were also among the figures sometimes considered to have been resurrected to physical immortality. According to Herodotus's Histories, the seventh century BC sage Aristeas of Proconnesus was first found dead, after which his body disappeared from a locked room. Later he found not only to have been resurrected but to have gained immortality.
Many other figures, like a great part of those who fought in the Trojan and Theban wars, Menelaus, and the historical pugilist Cleomedes of Astupalaea, were also believed to have been made physically immortal, but without having died in the first place. Indeed, in Greek religion, immortality originally always included an eternal union of body and soul. The philosophical idea of an immortal soul was a later invention, which, although influential, never had a breakthrough in the Greek world. As may be witnessed even into the Christian era, not least by the complaints of various philosophers over popular beliefs, traditional Greek believers maintained the conviction that certain individuals were resurrected from the dead and made physically immortal and that for the rest of us, we could only look forward to an existence as disembodied and dead souls.
This traditional religious belief in physical immortality was generally denied by the Greek philosophers. Writing his Lives of Illustrious Men (Parallel Lives) in the first century CE, the Middle Platonic philosopher Plutarch's chapter on Romulus gave an account of the mysterious disappearance and subsequent deification of this first king of Rome, comparing it to traditional Greek beliefs such as the resurrection and physical immortalization of Alcmene and Aristeas the Proconnesian, "for they say Aristeas died in a fuller's work-shop, and his friends coming to look for him, found his body vanished; and that some presently after, coming from abroad, said they met him traveling towards Croton." Plutarch openly scorned such beliefs held in traditional ancient Greek religion, writing, "many such improbabilities do your fabulous writers relate, deifying creatures naturally mortal."
The parallel between these traditional beliefs and the later resurrection of Jesus was not lost on the early Christians, as Justin Martyr argued: "when we say ... Jesus Christ, our teacher, was crucified and died, and rose again, and ascended into heaven, we propose nothing different from what you believe regarding those whom you consider sons of Zeus." (1 Apol. 21). There is, however, no belief in a general resurrection in ancient Greek religion, as the Greeks held that not even the gods were able to recreate flesh that had been lost to decay, fire or consumption.
The notion of a general resurrection of the dead was therefore apparently quite preposterous to the Greeks. This is made clear in Paul's Areopagus discourse. After having first told about the resurrection of Jesus, which makes the Athenians interested to hear more, Paul goes on, relating how this event relates to a general resurrection of the dead:
"Therefore having overlooked the times of ignorance, God is now declaring to men that all everywhere should repent, because He has fixed a day in which He will judge the world in righteousness through a Man whom He has appointed, having furnished proof to all men by raising Him from the dead." Now when they heard of the resurrection of the dead, some began to sneer, but others said, `We shall hear you again concerning this."
Christianity
Resurrection of Jesus
In Christianity, resurrection most critically concerns the Resurrection of Jesus, but also includes the resurrection of Judgment Day known as the Resurrection of the Dead by those Christians who subscribe to the Nicene Creed (which is the majority or Mainstream Christianity), as well as the resurrection miracles done by Jesus and the prophets of the Old Testament. Some churches distinguish between raising the dead (a resumption of mortal life) and a resurrection (the beginning of an immortal life).
Resurrection of Jesus
Christians regard the resurrection of Jesus as the central doctrine in Christianity. Others take the Incarnation of Jesus to be more central; however, it is the miracles – and particularly his Resurrection – which provide validation of his incarnation. According to Paul, the entire Christian faith hinges upon the centrality of the resurrection of Jesus and the hope for a life after death. The Apostle Paul wrote in his first letter to the Corinthians: If only for this life we have hope in Christ, we are to be pitied more than all men. But Christ has indeed been raised from the dead, the first fruits of those who have fallen asleep.
Resurrection
Miracles of Jesus § Resurrection of the dead
During the Ministry of Jesus on earth, before his death, Jesus commissioned his Twelve Apostles to, among other things, raise the dead. In the New Testament, Jesus is said to have raised several persons from death. These resurrections included the daughter of Jairus shortly after death, a young man in the midst of his own funeral procession, and Lazarus, who had been buried for four days. According to the Gospel of Matthew, after Jesus's resurrection, many of those previously dead came out of their tombs and entered Jerusalem, where they appeared to many.
Similar resurrections are credited to Christian apostles and saints. Peter allegedly raised a woman named Dorcas (called Tabitha), and Paul the Apostle revived a man named Eutychus who had fallen asleep and fell from a window to his death, according to the book of Acts. Proceeding the apostolic era, many saints were said to resurrect the dead, as recorded in Orthodox Christian hagiographies.[citation needed] St Columba supposedly raised a boy from the dead in the land of Picts .
Most Christians understand these miraculous resurrections to be of a different nature than the resurrection of Jesus and the future resurrection of the dead. The raising of Lazarus and others from the dead could also be called "resuscitations" or "reanimations", since the life given to them is presumably temporary in nature—there is no suggestion in the Bible or hagiographic traditions that these people became truly immortal. In contrast, the resurrection of Jesus and the future resurrection of the dead will abolish death once and for all (see Isaiah 25:8, 1 Corinthians 15:26, 2 Timothy 1:10, Revelation 21:4).
Resurrection of the Dead
Christianity started as a religious movement within 1st-century Judaism (late Second Temple Judaism), and it retains what the New Testament itself claims was the Pharisaic belief in the afterlife and Resurrection of the Dead. Whereas this belief was only one of many beliefs held about the World to Come in Second Temple Judaism, and was notably rejected by both the Sadducees and, according to Josephus, the Pharisees, this belief became dominant within Early Christianity and already in the Gospels of Luke and John included an insistence on the resurrection of the flesh. This was later rejected by gnostic teachings, which instead continued the Pauline insistence that flesh and bones had no place in heaven.
Most modern Christian churches continue to uphold the belief that there will be a final Resurrection of the Dead and World to Come, perhaps as prophesied by the Apostle Paul when he said: "...he hath appointed a day, in the which he will judge the world..." (Acts 17:31 KJV) and "...there shall be a resurrection of the dead, both of the just and unjust." (Acts 24:15 KJV).
Belief in the Resurrection of the Dead, and Jesus's role as judge, is codified in the Apostles' Creed, which is the fundamental creed of Christian baptismal faith. The Book of Revelation also makes many references about the Day of Judgment when the dead will be raised up.
Difference From Platonic philosophy
In Platonic philosophy and other Greek philosophical thought, at death the soul was said to leave the inferior body behind. The idea that Jesus was resurrected spiritually rather than physically even gained popularity among some Christian teachers, whom the author of 1 John declared to be antichrists. Similar beliefs appeared in the early church as Gnosticism. However, in Luke 24:39, the resurrected Jesus expressly states "behold my hands and my feet, that it is I myself. Handle me and see, for a spirit does not have flesh and bones as you see I have."
Islam
Belief in the "Day of Resurrection", Yawm al-Qiyāmah (Arabic: يوم القيامة) is also crucial for Muslims. They believe the time of Qiyāmah is preordained by God but unknown to man. The trials and tribulations preceding and during the Qiyāmah are described in the Qur'an and the hadith, and also in the commentaries of scholars. The Qur'an emphasizes bodily resurrection, a break from the pre-Islamic Arabian understanding of death.
Judaism and Samaritanism
There are three explicit examples in the Hebrew Bible of people being resurrected from the dead:
* The prophet Elijah prays and God raises a young boy from death (1 Kings 17:17-24)
* Elisha raises the son of the Shunammite woman (2 Kings 4:32-37); this was the very same child whose birth he previously foretold (2 Kings 4:8-16)
* A dead man's body that was thrown into the dead Elisha's tomb is resurrected when the body touches Elisha's bones (2 Kings 13:21)
During the period of the Second Temple, there developed a diversity of beliefs concerning the resurrection. The concept of resurrection of the physical body is found in 2 Maccabees, according to which it will happen through recreation of the flesh.[17] Resurrection of the dead also appears in detail in the extra-canonical books of Enoch,[18] in Apocalypse of Baruch, and 2 Esdras. According to the British scholar in ancient Judaism Philip R. Davies, there is “little or no clear reference … either to immortality or to resurrection from the dead” in the Dead Sea scrolls texts.
Both Josephus and the New Testament record that the Sadducees did not believe in an afterlife, but the sources vary on the beliefs of the Pharisees. The New Testament claims that the Pharisees believed in the resurrection, but does not specify whether this included the flesh or not. According to Josephus, who himself was a Pharisee, the Pharisees held that only the soul was immortal and the souls of good people will be reincarnated and “pass into other bodies,” while “the souls of the wicked will suffer eternal punishment.” Paul, who also was a Pharisee, said that at the resurrection what is "sown as a natural body is raised a spiritual body." Jubilees seems to refer to the resurrection of the soul only, or to a more general idea of an immortal soul.
According to Herbert C. Brichto, writing in Reform Judaism's Hebrew Union College Annual, the family tomb is the central concept in understanding biblical views of the afterlife. Brichto states that it is "not mere sentimental respect for the physical remains that is...the motivation for the practice, but rather an assumed connection between proper sepulture and the condition of happiness of the deceased in the afterlife".
According to Brichto, the early Israelites apparently believed that the graves of family, or tribe, united into one, and that this unified collectivity is to what the Biblical Hebrew term Sheol refers, the common Grave of humans. Although not well defined in the Tanakh, Sheol in this view was a subterranean underworld where the souls of the dead went after the body died. The Babylonians had a similar underworld called Aralu, and the Greeks had one known as Hades. For biblical references to Sheol see Genesis 42:38, Isaiah 14:11, Psalm 141:7, Daniel 12:2, Proverbs 7:27 and Job 10:21,22, and 17:16, among others. According to Brichto, other Biblical names for Sheol were: Abaddon (ruin), found in Psalm 88:11, Job 28:22 and Proverbs 15:11; Bor (the pit), found in Isaiah 14:15, 24:22, Ezekiel 26:20; and Shakhat (corruption), found in Isaiah 38:17, Ezekiel 28:8.
Zen Buddhism
There are stories in Buddhism where the power of resurrection was allegedly demonstrated in Chan or Zen tradition. One is the legend of Bodhidharma, the Indian master who brought the Ekayana school of India to China that subsequently became Chan Buddhism.
The other is the passing of Chinese Chan master Puhua (J., Fuke) and is recounted in the Record of Linji (J., Rinzai). Puhua was known for his unusual behavior and teaching style so it is no wonder that he is associated with an event that breaks the usual prohibition on displaying such powers. Here is the account from Irmgard Schloegl's "The Zen Teaching of Rinzai".
"One day at the street market Fuke was begging all and sundry to give him a robe. Everybody offered him one, but he did not want any of them. The master [Linji] made the superior buy a coffin, and when Fuke returned, said to him: "There, I had this robe made for you." Fuke shouldered the coffin, and went back to the street market, calling loudly: "Rinzai had this robe made for me! I am off to the East Gate to enter transformation" (to die)." The people of the market crowded after him, eager to look. Fuke said: "No, not today. Tomorrow, I shall go to the South Gate to enter transformation." And so for three days. Nobody believed it any longer. On the fourth day, and now without any spectators, Fuke went alone outside the city walls, and laid himself into the coffin. He asked a traveler who chanced by to nail down the lid.
The news spread at once, and the people of the market rushed there. On opening the coffin, they found that the body had vanished, but from high up in the sky they heard the ring of his hand bell."
Technological resurrection
Cryonics is the low-temperature preservation of humans who cannot be sustained by contemporary medicine, with the hope that healing and resuscitation may be possible in the future. Cryonics procedures ideally begin within minutes of cardiac arrest, and use cryoprotectants to prevent ice formation during cryopreservation.
However, the idea of cryonics also includes preservation of people long after death because of the possibility that brain encoding memory structure and personality may still persist or be inferable in the future. Whether sufficient brain information still exists for cryonics to successfully preserve may be intrinsically unprovable by present knowledge. Therefore, most proponents of cryonics see it as an intervention with prospects for success that vary widely depending on circumstances.
Russian Cosmist Nikolai Fyodorovich Fyodorov advocated resurrection of the dead using scientific methods. Fedorov tried to plan specific actions for scientific research of the possibility of restoring life and making it infinite. His first project is connected with collecting and synthesizing decayed remains of dead based on "knowledge and control over all atoms and molecules of the world".
The second method described by Fedorov is genetic-hereditary. The revival could be done successively in the ancestral line: sons and daughters restore their fathers and mothers, they in turn restore their parents and so on. This means restoring the ancestors using the hereditary information that they passed on to their children. Using this genetic method it is only possible to create a genetic twin of the dead person. It is necessary to give back the revived person his old mind, his personality. Fedorov speculates about the idea of "radial images" that may contain the personalities of the people and survive after death. Nevertheless, Fedorov noted that even if a soul is destroyed after death, Man will learn to restore it whole by mastering the forces of decay and fragmentation.
In his 1994 book The Physics of Immortality, American physicist Frank J. Tipler, an expert on the general theory of relativity, presented his Omega Point Theory which outlines how a resurrection of the dead could take place at the end of the cosmos. He posits that humans will evolve into robots which will turn the entire cosmos into a supercomputer which will, shortly before the big crunch, perform the resurrection within its cyberspace, reconstructing formerly dead humans (from information captured by the supercomputer from the past light cone of the cosmos) as avatars within its metaverse.
David Deutsch, British physicist and pioneer in the field of quantum computing, agrees with Tipler's Omega Point cosmology and the idea of resurrecting deceased people with the help of quantum computer but he is critical of Tipler's theological views.
Italian physicist and computer scientist Giulio Prisco presents the idea of "quantum archaeology", "reconstructing the life, thoughts, memories, and feelings of any person in the past, up to any desired level of detail, and thus resurrecting the original person via 'copying to the future'".
In his book Mind Children, roboticist Hans Moravec proposed that a future supercomputer might be able to resurrect long-dead minds from the information that still survived. For example, this information can be in the form of memories, filmstrips, medical records, and DNA.
Ray Kurzweil, American inventor and futurist, believes that when his concept of singularity comes to pass, it will be possible to resurrect the dead by digital recreation.
In their science fiction novel The Light of Other Days, Sir Arthur Clarke and Stephen Baxter imagine a future civilization resurrecting the dead of past ages by reaching into the past, through micro wormholes and with nanorobots, to download full snapshots of brain states and memories.
Both the Church of Perpetual Life and the Terasem Movement consider themselves transreligions and advocate for the use of technology to indefinitely extend the human lifespan.
Zombies
A zombie (Haitian Creole: zonbi; North Mbundu: nzumbe) can be either a fictional undead monster or a person in an entranced state believed to be controlled by a bokor or wizard. These latter are the original zombies, occurring in the West African Vodun religion and its American offshoots Haitian Vodou and New Orleans Voodoo.
Zombies became a popular device in modern horror fiction, largely because of the success of George A. Romero's 1968 film Night of the Living Dead and they have appeared as plot devices in various books, films and in television shows. Zombie fiction is now a sizable subgenre of horror, usually describing a breakdown of civilization occurring when most of the population become flesh-eating zombies – a zombie apocalypse. The monsters are usually hungry for human flesh, often specifically brains. Sometimes they are victims of a fictional pandemic illness causing the dead to reanimate or the living to behave this way, but often no cause is given in the story.
Disappearances (as distinct from resurrection)
As knowledge of different religions has grown, so have claims of bodily disappearance of some religious and mythological figures. In ancient Greek religion, this was a way the gods made some physically immortal, including such figures as Cleitus, Ganymede, Menelaus, and Tithonus. After his death, Cycnus was changed into a swan and vanished. In his chapter on Romulus from Parallel Lives, Plutarch criticises the continuous belief in such disappearances, referring to the allegedly miraculous disappearance of the historical figures Romulus, Cleomedes of Astypalaea, and Croesus. In ancient times, Greek and Roman pagan similarities were explained by the early Christian writers, such as Justin Martyr, as the work of demons, with the intention of leading Christians astray.
In somewhat recent years it has been learned that Gesar, the Savior of Tibet, at the end, chants on a mountain top and his clothes fall empty to the ground. The body of the first Guru of the Sikhs, Guru Nanak Dev, is said to have disappeared and flowers were left in place of his dead body.
Lord Raglan's Hero Pattern lists many religious figures whose bodies disappear, or have more than one sepulchre. B. Traven, author of The Treasure of the Sierra Madre, wrote that the Inca Virococha arrived at Cusco (in modern-day Peru) and the Pacific seacoast where he walked across the water and vanished.[46] It has been thought that teachings regarding the purity and incorruptibility of the hero's human body are linked to this phenomenon. Perhaps, this is also to deter the practice of disturbing and collecting the hero's remains. They are safely protected if they have disappeared.
The first such case mentioned in the Bible is that of Enoch (son of Jared, great-grandfather of Noah, and father of Methuselah). Enoch is said to have lived a life where he "walked with God", after which "he was not, for God took him" (Genesis 5:1–18).
In Deuteronomy (34:6) Moses is secretly buried. Elijah vanishes in a whirlwind 2 Kings (2:11). After hundreds of years these two earlier Biblical heroes suddenly reappear, and are seen walking with Jesus, then again vanish. Mark (9:2–8), Matthew (17:1–8) and Luke (9:28–33). The last time he is seen, Luke (24:51) alone tells of Jesus leaving his disciples by ascending into the sky.
St Machar's Cathedral (or, more formally, the Cathedral Church of St Machar) is a Church of Scotland church in Aberdeen, Scotland. It is located to the north of the city centre, in the former burgh of Old Aberdeen. Technically, St Machar's is no longer a cathedral but rather a high kirk, as it has not been the seat of a bishopsince 1690.
St Machar is said to have been a companion of St Columba on his journey to Iona. A fourteenth-century legend tells how God (or St Columba) told Machar to establish a church where a river bends into the shape of a bishop's crosier before flowing into the sea.
The River Don bends in this way just below where the Cathedral now stands. According to legend, St Machar founded a site of worship in Old Aberdeen in about 580. Machar's church was superseded by a Norman cathedral in 1131, shortly after David I transferred the See from Mortlach to Aberdeen.
Almost nothing of that original cathedral survives; a lozenge-decorated base for a capital supporting one of the architraves can be seen in the Charter Room in the present church.
After the execution of William Wallace in 1305, his body was cut up and sent to different corners of the country to warn other dissenters. His left quarter ended up in Aberdeen and is buried in the walls of the cathedral.
At the end of the thirteenth century Bishop Henry Cheyne decided to extend the church, but the work was interrupted by the Scottish Wars of Independence. Cheyne's progress included piers for an extended choir at the transept crossing. These pillars, with decorated capitals of red sandstone, are still visible at the east end of the present church.
Though worn by exposure to the elements after the collapse of the cathedral's central tower, these capitals are among the finest stone carvings of their date to survive in Scotland.
Bishop Alexander Kininmund II demolished the Norman cathedral in the late 14th century, and began the nave, including the granite columns and the towers at the western end. Bishop Henry Lichtoun completed the nave, the west front and the northern transept, and made a start on the central tower.
Bishop Ingram Lindsay completed the roof and the paving stones in the later part of the fifteenth century. Further work was done over the next fifty years by Thomas Spens, William Elphinstone and Gavin Dunbar; Dunbar is responsible for the heraldic ceiling and the two western spires.
The chancel was demolished in 1560 during the Scottish Reformation. The bells and lead from the roof were sent to be sold in Holland, but the ship sank near Girdle Ness.
The central tower and spire collapsed in 1688, in a storm, and this destroyed the choir and transepts. The west arch of the crossing was then filled in, and worship carried on in the nave only; the current church consists only of the nave and aisles of the earlier building.
The ruined transepts and crossing are under the care of Historic Scotland, and contain an important group of late medieval bishops' tombs, protected from the weather by modern canopies. The Cathedral is chiefly built of outlayer granite. On the unique flat panelled ceiling of the nave (first half of the 16th Century) are the heraldic shields of the contemporary kings of Europe, and the chief earls and bishops of Scotland.
The Cathedral is a fine example of a fortified kirk, with twin towers built in the fashion of fourteenth-century tower houses. Their walls have the strength to hold spiral staircases to the upper floors and battlements. The spires which presently crown the
Though worn by exposure to the elements after the collapse of the cathedral's central tower, these capitals are among the finest stone carvings of their date to survive in Scotland.
Bishop Alexander Kininmund II demolished the Norman cathedral in the late 14th century, and began the nave, including the granite columns and the towers at the western end. Bishop Henry Lichtoun completed the nave, the west front and the northern transept, and made a start on the central tower.
Bishop Ingram Lindsay completed the roof and the paving stones in the later part of the fifteenth century. Further work was done over the next fifty years by Thomas Spens, William Elphinstone and Gavin Dunbar; Dunbar is responsible for the heraldic ceiling and the two western spires.
The chancel was demolished in 1560 during the Scottish Reformation. The bells and lead from the roof were sent to be sold in Holland, but the ship sank near Girdle Ness.
The central tower and spire collapsed in 1688, in a storm, and this destroyed the choir and transepts. The west arch of the crossing was then filled in, and worship carried on in the nave only; the current church consists only of the nave and aisles of the earlier building.
The ruined transepts and crossing are under the care of Historic Scotland, and contain an important group of late medieval bishops' tombs, protected from the weather by modern canopies. The Cathedral is chiefly built of outlayer granite. On the unique flat panelled ceiling of the nave (first half of the 16th Century) are the heraldic shields of the contemporary kings of Europe, and the chief earls and bishops of Scotland.
Bishops Gavin Dunbar and Alexander Galloway built the western towers and installed the heraldic ceiling, featuring 48 coats of arms in three rows of sixteen. Among those shown are:
* Pope Leo X's coat of arms in the centre, followed in order of importance by those of the Scottish archbishops and bishops.
* the Prior of St Andrews, representing other Church orders.
* King's College, the westernmost shield.
* Henry VIII of England, James V of Scotland and multiple instances for the Holy Roman Emperor Charles V, who was also King of Spain, Aragon, Navarre and Sicily at the time the ceiling was created.
* St Margaret of Scotland, possibly as a stand-in for Margaret Tudor, James V's mother, whose own arms would have been the marshalled arms of England and Scotland.
* the arms of Aberdeen and of the families Gordon, Lindsay, Hay and Keith.
The ceiling is set off by a frieze which starts at the north-west corner of the nave and lists the bishops of the see from Nechtan in 1131 to William Gordon at the Reformation in 1560. This is followed by the Scottish monarchs from Máel Coluim II to Mary, Queen of Scots.
Notable figures buried in the cathedral cemetery include the author J.J. Bell, Robert Brough, Gavin Dunbar, Robert Laws, a missionary to Malawi and William Ogilvie of Pittensear—the ‘rebel professor’.
There has been considerable investment in recent years in restoration work and the improvement of the display of historic artefacts at the Cathedral.
The battlements of the western towers, incomplete for several centuries, have been renewed to their original height and design, greatly improving the appearance of the exterior. Meanwhile, within the building, a number of important stone monuments have been displayed to advantage.
These include a possibly 7th-8th century cross-slab from Seaton (the only surviving evidence from Aberdeen of Christianity at such an early date); a rare 12th century sanctuary cross-head; and several well-preserved late medieval effigies of Cathedral clergy, valuable for their detailed representation of contemporary dress.
A notable modern addition to the Cathedral's artistic treasures is a carved wooden triptych commemorating John Barbour, archdeacon of Aberdeen (d. 1395), author of The Brus.