These are images of Saturn’s moon Titan, captured by the NASA/ESA/CSA James Webb Space Telescope’s NIRCam instrument on 4 November 2022. The image on the left uses a filter sensitive to Titan’s lower atmosphere. The bright spots are prominent clouds in the northern hemisphere. The image on the right is a color composite image.

Titan is the only moon in the Solar System with a dense atmosphere, and it is also the only planetary body other than Earth that currently has rivers, lakes, and seas. Unlike Earth, however, the liquid on Titan’s surface is composed of hydrocarbons including methane and ethane, not water. Its atmosphere is filled with thick haze that obscures visible light reflecting off the surface.

Scientists have waited for years to use Webb’s infrared vision to study Titan’s atmosphere, including its fascinating weather patterns and gaseous composition, and also see through the haze to study albedo features (bright and dark patches) on the surface. Further Titan data are expected from NIRCam and NIRSpec as well as the first data from Webb’s Mid-Infrared Instrument (MIRI) in May or June of 2023. The MIRI data will reveal an even greater part of Titan’s spectrum, including some wavelengths that have never before been seen. This will give scientists information about the complex gases in Titan’s atmosphere, as well as crucial clues to deciphering why Titan is the only moon in the Solar System with a dense atmosphere.

[Image Description: Side-by-side images of Saturn’s moon Titan, captured by Webb’s Near-Infrared Camera on 4 November 2022, with clouds and other features visible. Left image is various shades of red. Right image is shades of white, blue, and brown.]

Note: This post highlights data from Webb science in progress, which has not yet been through the peer-review process.

Credits: NASA, ESA, CSA, A. Pagan (STScI), JWST Titan GTO Team; CC BY 4.0

Glasgow, host of the 26th UN Climate Change Conference of Parties (COP26), is featured in this image captured by the Copernicus Sentinel-2 mission.

Situated in west-central Scotland, Glasgow is the largest city in the country. It lies along both banks of the River Clyde, the ninth-longest river in the United Kingdom and the third-longest in Scotland. The city occupies much of the lower Clyde valley, and its suburbs extend into the surrounding districts.

Edinburgh, Scotland’s capital, can be seen in the centre-right of the image, located in Lothian on the southern shore of the Firth of Forth. Both Edinburgh and Glasgow, along with Stirling and Dundee, all lie in the Central Lowlands, where over half of Scotland’s population lives.

The Highlands, visible in the upper-left of the image, is the largest region in Scotland covering more than 25 600 sq km of land and is home to stunning scenery. The area is divided in two parts: the Great Glen divides the Grampian Mountains to the southeast from the northwest Highlands. The area is very sparsely populated, with many mountain ranges dominating the region and includes the highest mountain in the British Isles, Ben Nevis, as well as the legendary Loch Ness.

From 31 October to 12 November, the COP26 summit will take place in Glasgow – bringing together parties to accelerate action towards the goals of the Paris Agreement and the UN Framework Convention on Climate Change.

As in previous years, ESA will have a strong presence at COP26. ESA’s theme at COP26 will be ‘Taking the pulse of the planet from space and supporting climate action’ which aims to demonstrate the role of ESA’s missions and satellite data to strengthen our understanding of climate from space. This will support policymakers, society, businesses and communities to mitigate and adapt to a changing climate and develop resilience in support of the UNFCC Paris agreement.

During COP26, the much-anticipated documentary which covers the ESA-led science expedition to the Gorner Glacier in Switzerland will be released for the first time. The documentary follows ESA astronaut Luca Parmitano, along with Susanne Mecklenburg, Head of ESA’s Climate Office, and their scientific team to one of the biggest ice masses in the Alps: the Gorner Glacier. Owing to its dramatic retreat, the glacier is one of the most extensively studies glaciers in the world. Read more about the expedition and watch the documentary trailer.

This image is also featured on the Earth from Space video programme.

Credits: contains modified Copernicus Sentinel data (2019), processed by ESA, CC BY-SA 3.0 IGO

Our planetary neighbours are getting into the holiday spirit with this pair of festive silhouettes spotted by ESA’s Mars Express. The defined wings of an angelic figure, complete with halo, can be seen sweeping up and off the top of the frame in this image from Mars Express’ High Resolution Stereo Camera, while a large heart sits just right of centre. The dark colour of these two shapes is due to the composition of the constituent dune fields, which largely contain sands rich in dark, rock-forming minerals that are also found on Earth.

This image comprises data gathered by ESA’s Mars Express using its High Resolution Stereo Camera (HRSC) on 8 November 2020 (orbit 21305). The ground resolution is approximately 15 m/pixel and the images are centred at about 148°E/78°S. This image was created using data from the nadir and colour channels of the HRSC. The nadir channel is aligned perpendicular to the surface of Mars, as if looking straight down at the surface. North is to the left.

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Credits: ESA/DLR/FU Berlin, CC BY-SA 3.0 IGO

By combining images of the iconic Pillars of Creation from two cameras aboard the NASA/ESA/CSA James Webb Space Telescope, the Universe has been framed in its infrared glory. Webb’s near-infrared image was fused with its mid-infrared image, setting this star-forming region ablaze with new details.

Myriad stars are spread throughout the scene. The stars primarily show up in near-infrared light, marking a contribution of Webb’s Near-Infrared Camera (NIRCam). Near-infrared light also reveals thousands of newly formed stars – look for bright orange spheres that lie just outside the dusty pillars.

In mid-infrared light, the dust is on full display. The contributions from Webb’s Mid-Infrared Instrument (MIRI) are most apparent in the layers of diffuse, orange dust that drape the top of the image, relaxing into a V. The densest regions of dust are cast in deep indigo hues, obscuring our view of the activities inside the dense pillars.

Dust also makes up the spire-like pillars that extend from the bottom left to the top right. This is one of the reasons why the region is overflowing with stars – dust is a major ingredient of star formation. When knots of gas and dust with sufficient mass form in the pillars, they begin to collapse under their own gravitational attraction, slowly heat up, and eventually form new stars. Newly formed stars are especially apparent at the edges of the top two pillars – they are practically bursting onto the scene.

At the top edge of the second pillar, undulating detail in red hints at even more embedded stars. These are even younger, and are quite active as they form. The lava-like regions capture their periodic ejections. As stars form, they periodically send out supersonic jets that can interact within clouds of material, like these thick pillars of gas and dust. These young stars are estimated to be only a few hundred thousand years old, and will continue to form for millions of years.

Almost everything you see in this scene is local. The distant universe is largely blocked from our view both by the interstellar medium, which is made up of sparse gas and dust located between the stars, and a thick dust lane in our Milky Way galaxy. As a result, the stars take center stage in Webb’s view of the Pillars of Creation.

The Pillars of Creation is a small region within the vast Eagle Nebula, which lies 6,500 light-years away.

Revisit Webb’s near-infrared image and its its mid-infrared image. The Pillars of Creation was made famous by the NASA/ESA Hubble Space Telescope in 1995, and again in 2014.

MIRI was contributed by ESA and NASA, with the instrument designed and built by a consortium of nationally funded European Institutes (The MIRI European Consortium) in partnership with JPL and the University of Arizona.

Webb’s NIRCam was built by a team at the University of Arizona and Lockheed Martin’s Advanced Technology Center.

Credits: NASA, ESA, CSA, STScI, J. DePasquale (STScI), A. Pagan (STScI), A. M. Koekemoer (STScI); CC BY 4.0

The Atmosphere-Space Interactions Monitor or ASIM, mounted outside the European laboratory of the International Space Station, enters its second year of science operations.

Launched in April 2018, the payload began operating on 14 June 2018 and has been studying thunderstorms 400 km above Earth ever since.

Specifically, ASIM is on the hunt for elusive electrical discharges in the upper atmosphere, or lightning that extends upwards into space. These discharges have alluring names like red sprites, blue jets and elves and have been reported by pilots over the years.

Besides these phenomena ASIM is also studying terrestrial Gamma-ray flashes. These are high-energy discharges of photons that propagate out into space.

All these light shows appear to be more common than originally thought and scientists are eager to know more about how they could influence Earth’s climate.

ASIM is outfitted with a collection of optical cameras, photometers and an X- and gamma-ray detector designed to track and record the ‘transient luminous events’ and terrestrial gamma-ray flashes.

Scientists knew these terrestrial Gamma-ray flashes existed because they were detected by astronomy spacecraft in the 1990s, but the ‘MXGS’ instrument on ASIM is looking down at Earth from the International Space Station and scans the globe to pinpoint where the gamma-rays are coming from, the first high-energy instrument to generate images of our planet in X-rays.

After just one year in operation, the ASIM science team published the first image of Earth in X-rays at high spatial resolution.

As ASIM can better detect terrestrial gamma-ray flashes it is revealing more details than ever before, as well as showing where they originate. Scientists can then pool data from other spacecraft and ground-based weather stations to complete the overview.

“ASIM is working really well for what is was built for, but it is also producing great secondary science,” says Astrid Orr, ESA’s physical sciences coordinator. “We sometimes get nice bonuses from ASIM.”

In addition to terrestrial gamma rays, ASIM is also catching glimpses of other types of events from its vantage point on the International Space Station. The payload has clocked meteorites, for instance.

“What really inspires me is that, besides doing fantastic experiments inside the Station, we have an external payload giving us more than what it was launched for. This illustrates what a multipurpose scientific laboratory the International Space Station is” adds Astrid.

The data ASIM is generating are now available for download and can be consulted at the ASIM Science Data Center website upon submission of a proposal to the science team.

ASIM was developed by TERMA for ESA for the ASIM Science Team, coordinated by the Technical University of Denmark, and is operated from the Belgian User Support and Operations Centre.

Credits: NASA

The ghostly green glow in this image reveals the presence of 46P Wirtanen – a relatively small comet with an estimated diameter of 1.2 kilometers. Had the path of history taken a different course, we would have much more than estimates about this Jupiter-family comet.

Completing one full orbit of the Sun every 5.4 years, 46P/Wirtanen was the original target of ESA’s Rosetta spacecraft. With the original launch window missed, the now famous comet 67P/Churyumov-Gerasimenko instead became the first ever visited by a human spacecraft and probe.

Five years ago this week, on 19 January 2014, Rosetta’s internal alarm clock woke up the spacecraft following a 31-month deep-space hibernation. In one of the most exciting moments for Rosetta scientists and mission operators on Earth, the spacecraft called back home confirming everything was working fine and that it has survived the most distant part of its journey.

The recent visit of 46P Wirtanen reminds us of the remarkable achievement that was the Rosetta mission, the dynamic nature of space exploration and the flexibility of mission teams who seamlessly moved from one green and remote Solar System comet to another, rubber duck shaped body.

This stunning photo was taken by photographer Ollie Taylor over the famous ‘Durdle Door’ rock arch on the Dorset Jurassic Coast, on the evening of 9 December 2018. Check out more of Ollie’s images on his website.

Credits: Ollie Taylor. Used with permission

Observed with the NASA/ESA Hubble Space Telescope, the faint galaxy featured in this image is known as UGC 12588. Unlike many spiral galaxies, UGC 12588 displays neither a bar of stars across its centre nor the classic prominent spiral arm pattern. Instead, to a viewer, its circular, white and mostly unstructured centre makes this galaxy more reminiscent of a cinnamon bun than a mega-structure of stars and gas in space.

Lying in the constellation of Andromeda in the Northern hemisphere, this galaxy is classified as a spiral galaxy. Unlike the classic image of a spiral galaxy, however, the huge arms of stars and gas in UGC 12588 are very faint, undistinguished, and tightly wound around its centre. The clearest view of the spiral arms comes from the bluer stars sprinkled around the edges of the galaxy that highlight the regions where new star formation is most likely taking place.

Credits: ESA/Hubble & NASA, R. Tully; CC BY 4.0 - Acknowledgement: Gagandeep Anand

The NASA/ESA Hubble Space Telescope’s Wide Field Camera 3 observed Saturn on 20 June 2019 as the planet made its closest approach to Earth this year, at approximately 1.36 billion kilometres away.

Saturn hosts many recognisable features, most notably its trademark ring system, which is now tilted towards Earth. This gives us a magnificent view of its bright icy structure. Hubble resolves numerous ringlets and the fainter inner rings. Dutch astronomer Christiaan Huygens first identified the rings in 1655 and thought they were a continuous disk encircling the planet, but we now know them to be composed of orbiting particles of ice and dust. Though all of the gas giants boast rings, Saturn’s are the largest and most spectacular.

The age of Saturn’s ring system continues to be debated. And, even more perplexingly, it’s unknown what cosmic event formed the rings. There is no consensus among planetary astronomers today.

Read more here.

Credits: NASA, ESA, A. Simon (Goddard Space Flight Center), and M.H. Wong (University of California, Berkeley); CC BY 4.0

Appearing within the boundless darkness of space, the NASA/ESA Hubble Space Telescope’s snapshot of NGC 34 looks more like an otherworldly, bioluminescent creature from the deep oceans than a galaxy. Lying in the constellation Cetus (The Sea Monster), the galaxy’s outer region appears almost translucent, pinpricked with stars and strange wispy tendrils.

The main cause for this galaxy’s odd appearance lies in its past. If we were able to reverse time by a few million years, we would see two beautiful spiral galaxies on a direct collision course. When these galaxies collided into one another, their intricate patterns and spiral arms were permanently disturbed. This image shows the galaxy's bright centre, a result of this merging event that has created a burst of new star formation and lit up the surrounding gas. As the galaxies continue to intertwine and become one, NGC 34’s shape will become more like that of an peculiar galaxy, devoid of any distinct shape.

In the vastness of space, collisions between galaxies are quite rare events, but they can be numerous in mega-clusters containing hundreds or even thousands of galaxies.

Credits: ESA/Hubble & NASA, A. Adamo et al.; CC BY 4.0

The Copernicus Sentinel-2 mission takes us over Carrara – an Italian city known especially for its world-famous marble.

Carrara lies along the Carrione River, in northern Tuscany, around 130 km from Florence. It can be seen just above the centre of the image, stretching into the mountains.

The city is famous for its white or blue-grey marble, called Carrara, taken from nearby quarries in the Apuan Alps, a mountain range that stretches for approximately 55 km and reaching around 2000 m high. What appears as snow cover on the rugged mountains is actually bright white marble, contrasting with Tuscany’s lush green vegetation.

Carrara marble is one of the most prestigious marbles in the world, with its quarries producing more marble than any other place on Earth. The unique stone was formed by calcite-rich shells left behind by marine organisms when they die. When water bodies evaporate, the deposited remains form limestone, and when buried under multi-tonne layers of rock, the intense heat and pressure cause the limestone to metamorphose into marble.

The special quality of the Carrara marble has made it a popular resource for many famous sculptures, including Michelangelo’s Pietà, and has been used for some of the most remarkable buildings in Ancient Rome, including the Pantheon and Trajan’s Column.

Also featured in this summery image from Sentinel-2 are the towns of Forte dei Marmi, Pietrasanta, Lido di Camaiore and Viareggio. Marina di Carrara, southwest of the city, is a beach resort on the Ligurian Sea, with port facilities for transporting and shipping marble. The most popular resorts and beaches nearby are those at Marina di Carrara and Marina di Massa, both of which become very crowded during the summer, especially with Italian holidaymakers. La Spezia, a major naval base and the second largest city in the Liguria region, is visible in the top-left of the image.

Copernicus Sentinel-2 is based on a constellation of two identical satellites in the same orbit, 180° apart for optimal coverage and data delivery. Together they cover all Earth’s land surfaces, large islands, inland and coastal waters every five days at the equator.

This image is also featured on the Earth from Space video programme.

Credits: contains modified Copernicus Sentinel data (2021), processed by ESA, CC BY-SA 3.0 IGO

A global infrared mosaic of Saturn’s moon Enceladus created using a complete dataset from the Cassini spacecraft has revealed new detail on the moon’s surface.

Cassini orbited Saturn and its moons from 2004 to 2017. The mission ended when the spacecraft was intentionally plunged into the planet’s atmosphere, but new discoveries are still being made with the data.

During the mission lifetime, Cassini flew by Enceladus 147 times, with 23 close encounters of the icy moon. The Visual and Infrared Mapping Spectrometer (VIMS) collected data that can be used to reveal information on the temperature and composition of the surface, as well as the sizes and crystallinity of ice grains.

A study published in Icarus has produced a global spectral mosaic using the complete VIMS dataset. The full-colour images were created by combining three IR channels of the VIMS spectro-imager, represented here by red, green, and blue colours, and overlapping these on a mosaic created using the Imaging Science Subsystem on Cassini by another team.

The image shows five infrared views of Enceladus centred on the leading side, the Saturn-facing side, and the trailing side in the top row, and the North and South Pole in the bottom row. Click here for an annotated version. The globe can also be explored interactively.

The scientists used a photometric correction to reveal new details on the surface of the moon. Enceladus has a surface composed almost of pure water ice, which makes it highly reflective, but the observed brightness depends on the properties of the surface material, the surface shape, and the angle at which it is viewed. Correcting for these variations was necessary to show the differences in composition and physical state at the surface.

By using these improved photometric corrections, the scientists have been able to reveal spectral variations which correspond to the different colours in the images. These are particularly striking in the region with four large tectonic faults known as the Tiger Stripes at the South Pole. The image of the South Pole also reveals a clear boundary between terrains where the light red colour meets the blue region. The smooth red colour seen in the first image is likely due to recently exposed freshwater ice. This could be the surface signature of hotspots on the seafloor.

In the future the scientists plan to apply their technique to other icy moons to compare them with Enceladus. Similar infrared mapping by the Juice and Europa Clipper missions will be able to detect recent activity on Jupiter’s moons Europa and Ganymede.

The Cassini mission is a cooperative project between NASA, ESA, and Italy's ASI space agency.

Credits: NASA/JPL-Caltech/University of Arizona/LPG/CNRS/University of Nantes/Space Science Institute

The Tana River, Kenya’s longest river, is featured in this false-colour image captured by the Copernicus Sentinel-2 mission.

The Tana River flows for around 1000 km from the Aberdare Mountains, west of Nyeri, running eastwards before veering south around the massif of Mount Kenya, and opening onto a wide valley, pictured here, where it meanders through a floodplain often subject to inundation. The river then continues its journey before entering the Indian Ocean at Formosa Bay, Kipini.

The river is known for its extraordinary biodiversity, as it provides water and life for wild animals, nomads and their livestock, as well as for agricultural purposes.

Some of the Tana’s tributaries as well as several smaller, seasonal rivers, known as lagas, that only flow during the rainy season, are visible flowing in an east-west direction in the image. The river beds support livestock and wildlife during the dry season owing to their ability to retain water.

This false-colour image, captured on 25 February 2020, was processed in a way that included the near-infrared channel. This type of band combination from Copernicus Sentinel-2 is most commonly used to assess plant density and health, as plants reflect near-infrared and green light, while absorbing red. Since they reflect more near-infrared than green, dense, plant-covered land appears in bright red.

It is easy to pick out the narrow band of riparian forest visible along the banks of the river in the image. The riparian forest usually thrives year-round, although its extent is highly dependent on seasonal flooding and ground water recharge by the Tana.

This image was captured during the area’s wet season, where the small tributaries of the Tana are highly visible and a significant amount of vegetation can be seen. If the image had been captured during the dry season (around June-September), the smaller tributaries and the vegetation growing around them would have dried up.

The river flows alongside the town of Garissa, the capital of Garissa County, and is visible as a greyish patch of land on the east side of the river. Around 5 km south of Garissa lies the Bour-Algi Giraffe Sanctuary, home to around 1000 giraffes and endangered wildlife including the Rothschild giraffe and gerenuk – a long-necked antelope found in the region.

Copernicus Sentinel-2 is a two-satellite mission. Each satellite carries a high-resolution camera that images Earth’s surface in 13 spectral bands. The mission is mostly used to track changes in the way land is being used and to monitor the health of vegetation.

This image is also featured on the Earth from Space video programme.

Credits: contains modified Copernicus Sentinel data (2020), processed by ESA, CC BY-SA 3.0 IGO

The Pillars of Creation are set off in a kaleidoscope of colour in the NASA/ESA/CSA James Webb Space Telescope’s near-infrared-light view. The pillars look like arches and spires rising out of a desert landscape, but are filled with semi-transparent gas and dust, and ever changing. This is a region where young stars are forming – or have barely burst from their dusty cocoons as they continue to form.

Protostars are the scene-stealers in this Near-Infrared Camera (NIRCam) image. These are the bright red orbs that sometimes appear with eight diffraction spikes. When knots with sufficient mass form within the pillars, they begin to collapse under their own gravity, slowly heat up, and eventually begin shining brightly.

Along the edges of the pillars are wavy lines that look like lava. These are ejections from stars that are still forming. Young stars periodically shoot out jets that can interact within clouds of material, like these thick pillars of gas and dust. This sometimes also results in bow shocks, which can form wavy patterns like a boat does as it moves through water. These young stars are estimated to be only a few hundred thousand years old, and will continue to form for millions of years.

Although it may appear that near-infrared light has allowed Webb to “pierce through” the background to reveal great cosmic distances beyond the pillars, the interstellar medium stands in the way, like a drawn curtain.

This is also the reason why there are no distant galaxies in this view. This translucent layer of gas blocks our view of the deeper universe. Plus, dust is lit up by the collective light from the packed “party” of stars that have burst free from the pillars. It’s like standing in a well-lit room looking out a window – the interior light reflects on the pane, obscuring the scene outside and, in turn, illuminating the activity at the party inside.

Webb’s new view of the Pillars of Creation will help researchers revamp models of star formation. By identifying far more precise star populations, along with the quantities of gas and dust in the region, they will begin to build a clearer understanding of how stars form and burst out of these clouds over millions of years.

The Pillars of Creation is a small region within the vast Eagle Nebula, which lies 6500 light-years away.

Webb’s NIRCam was built by a team at the University of Arizona and Lockheed Martin’s Advanced Technology Center.

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NASA, ESA, CSA, STScI; J. DePasquale, A. Koekemoer, A. Pagan (STScI); CC BY 4.0

ESA Young Graduate Trainee Vedant Paul inspecting the Young Professionals Satellite on a shaker table for vibration testing at the Agency’s Mechanical Systems Laboratory. The two cameras seen at the top of this 50-cm tall payload will capture imagery of Europe’s inaugural Ariane 6 flight from the inside.

When ESA announced the opportunity to propose payloads for the first Ariane 6 flight, ESA Young Professionals came together to design a mission mounted to the payload platform that would image the fairing separation and deployment of satellites from the launcher, as well as return views from orbit.

A core team of about 30 Young Professionals from across the Agency’s Establishments, Directorates and disciplines has been working in its spare time to design, build and test the Young Professionals Satellite, YPSat for short, with advice coming from experts in ESA’s Directorates of Technology Engineering and Quality, Operations and Space Transportation Systems.

“Along with returning unique imagery from a historic flight, YPSat will also gather magnetic data along Ariane 6’s trajectory.” comments Young Graduate Trainee Julien Krompholtz, leading the YPSat effort. “Combining mission development with our everyday work is not easy, but it is an opportunity to build additional skills alongside our projects. Creating and developing a spacecraft that we ourselves have directly initiated all the way into space is an amazing opportunity.”

Find out more on the new ESA Young Professionals Satellites website.

Credits: ESA

The joint European-Japanese BepiColombo mission captured this view of Venus on 10 August 2021 as the spacecraft passed the planet for a gravity assist manoeuvre.

The image was taken at 13:57:56 UTC by the Mercury Transfer Module’s Monitoring Camera 3, when the spacecraft was 1573 km from Venus. Closest approach of 552 km took place shortly before, at 13:51:54 UTC.

The cameras provide black-and-white snapshots in 1024 x 1024 pixel resolution. The image has been lightly processed to enhance contrast and use the full dynamic range. A small amount of optical vignetting is seen in the bottom left of the image.

The high-gain antenna of the Mercury Planetary Orbiter and part of the body of the spacecraft are visible in front of Venus, at top left.

The manoeuvre, the second at Venus and the third of nine flybys overall, helped steer the spacecraft on course for Mercury. During its seven-year cruise to the smallest and innermost planet of the Solar System, BepiColombo makes one flyby at Earth, two at Venus and six at Mercury to brake against the gravitational pull of the Sun in order to enter orbit around Mercury. Its first Mercury flyby will take place 1-2 October 2021.

BepiColombo, which comprises ESA’s Mercury Planetary Orbiter and the Mercury Magnetospheric Orbiter of the Japan Aerospace Exploration Agency (JAXA), is scheduled to reach its target orbit around the smallest and innermost planet of the Solar System in 2025.

Credits: ESA/BepiColombo/MTM; CC BY-SA 3.0 IGO

The NASA/ESA Hubble Space Telescope has observation time devoted to Saturn each year, thanks to the Outer Planet Atmospheres Legacy (OPAL) program, and the dynamic gas giant planet always shows us something new. This latest image heralds the start of Saturn's "spoke season" with the appearance of two smudgy spokes in the B ring, on the left in the image.

The spokes are enigmatic features which appear across Saturn’s rings. Their presence and appearance varies with the seasons — like Earth, Saturn is tilted on its axis and therefore has four seasons. With Saturn's much larger orbit, each season lasts approximately seven Earth years. Equinox occurs when the rings are tilted edge-on to the Sun and marks the height of spokes’ visibility, while during a solstice when the Sun is at its highest or lowest latitude, the spokes disappear.

The shape and shading of spokes varies — they can appear light or dark, depending on the viewing angle, and sometimes appear more like blobs than classic radial spoke shapes, as seen here. The ephemeral features don't last long, but as the planet's autumnal equinox approaches on 6 May 2025, more will appear.

Scientists will be looking for clues to explain the cause and nature of the spokes. It's suspected they are caused by interaction between Saturn's magnetic field and the solar wind, which also causes aurorae to appear on the planet. The hypothesis is that spokes are the smallest, dust-sized, icy ring particles being temporarily electrically charged and levitated, but this has not been confirmed.

Saturn's last equinox occurred in 2009, while the NASA/ESA/ASI Cassini spacecraft was orbiting the gas giant planet for close-up reconnaissance. With Cassini's mission completed in 2017, Hubble is continuing the work of long-term monitoring of changes on Saturn and the other outer planets.

[Image description: A close-up image of the planet Saturn. The rings are level with the viewer, and tilted slightly down.]

Credits: ESA/Hubble, NASA & A. Simon, A. Pagan (STScI); CC BY 4.0

The first anniversary image from the NASA/ESA/CSA James Webb Space Telescope displays star birth like it’s never been seen before, full of detailed, impressionistic texture. The subject is the Rho Ophiuchi cloud complex, the closest star-forming region to Earth. It is a relatively small, quiet stellar nursery, but you’d never know it from Webb’s chaotic close-up. Jets bursting from young stars crisscross the image, impacting the surrounding interstellar gas and lighting up molecular hydrogen, shown in red. Some stars display the telltale shadow of a circumstellar disc, the makings of future planetary systems.

The young stars at the centre of many of these discs are similar in mass to the Sun or smaller. The heftiest in this image is the star S1, which appears amid a glowing cave it is carving out with its stellar winds in the lower half of the image. The lighter-coloured gas surrounding S1 consists of polycyclic aromatic hydrocarbons, a family of carbon-based molecules that are among the most common compounds found in space.

[Image description: Red dual opposing jets coming from young stars fill the darker top half of the image, while a glowing pale-yellow, cave-like structure is bottom centre, tilted toward two o’clock, with a bright star at its centre. The dust of the cave structure becomes wispy toward eight o’clock. Above the arched top of the dust cave three groupings of stars with diffraction spikes are arranged. A dark cloud sits at the top of the arch of the glowing dust cave, with one streamer curling down the right-hand side. The dark shadow of the cloud appears pinched in the centre, with light emerging in a triangle shape above and below the pinch, revealing the presence of a star inside the dark cloud. The image’s largest jets of red material emanate from within this dark cloud, thick and displaying structure like the rough face of a cliff, glowing brighter at the edges. At the top centre of the image, a star displays another, larger pinched dark shadow, this time vertically. To the left of this star is a more wispy, indistinct region.]

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Credits: NASA, ESA, CSA

The Sun as seen by Solar Orbiter in extreme ultraviolet light from a distance of roughly 75 million kilometres. The image is a mosaic of 25 individual images taken on 7 March by the high resolution telescope of the Extreme Ultraviolet Imager (EUI) instrument. Taken at a wavelength of 17 nanometers, in the extreme ultraviolet region of the electromagnetic spectrum, this image reveals the Sun’s upper atmosphere, the corona, which has a temperature of around a million degrees Celsius. In total, the final image contains more than 83 million pixels in a 9148 x 9112 pixel grid, making it the highest resolution image of the Sun’s full disc and outer atmosphere, the corona, ever taken.

An image of Earth is also included for scale, at the 2 o’clock position.

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Credits: ESA & NASA/Solar Orbiter/EUI team; Data processing: E. Kraaikamp (ROB)

The Moon seen from the International Space Station by ESA astronaut Thomas Pesquet on 30 May 2021.

Thomas commented on the photo: "The Cupola windows have scratch panes on the inside, that protect the windows from camera lenses bumping into it... but they are quite scratched over the years and it makes it very difficult to take pictures with the big lenses… only one window has a bump shield that slides open. I was only too happy to see the Moon frame itself perfectly in that window. Serendipity! The Moon is symbolically getting closer all the time with new programmes and humans set to land on our natural satellite in the next few years, brought there by the European Service Module for NASA's Orion spacecraft..."

Latest updates on the Alpha mission can be found via @esaspaceflight on Twitter, with more details on ESA’s exploration blog.

Background information on the Alpha mission with a brochure.

Credits: ESA/NASA–T. Pesquet

The heart of the Exospheric Mass Spectrometer (EMS) is visible in this image of the key sensor that will study the abundance of lunar water and water ice for upcoming missions to the Moon.

This spectrometer is being delivered to NASA today as part of the PITMS instrument for its launch to the Moon later this year.

EMS is based on an ‘ion trap’, an ingenious detector device that allows researchers to identify and quantify sample atoms and molecules in a gas and allows to establish a corresponding mass spectrum. Scientists at The Open University and RAL Space are developing EMS under an ESA contract.

Lunar molecules entering the sensor are bombarded by electrons emitted by a heated wire to create ions. The resulting ions are stored within an electric field formed by a set of precisely-shaped electrodes. The ions are then released from this ‘trap’ in order of increasing mass/charge ratio into the detector that identifies and quantifies their chemical makeup.

This will allow the instrument to measure water and other molecules in the very thin atmosphere of the Moon throughout the lunar day to study a lunar ‘water cycle’ concept.

The PITMS instrument will be part of a lunar lander that will arrive on the Moon on NASA’s Astrobotic mission taking commercial lunar payloads to the Valles Mortis region in 2021.

A similar Mass Spectrometer is also developed for ESA’s Prospect mission to study lunar water ice on board the Russian Luna-27 lander, set for launch in 2025. The platform will sample potential resources on the Moon to prepare technologies for future sustainable exploration.

“ESA’s Exospheric Mass Spectrometer will not only acquire science data but also test our latest environmental monitoring technology for planetary environments,” says Roland Trautner, ESA project lead for EMS.

“Instruments like EMS allow the detection of the impact of human activities on the lunar environment, and understanding these changes allows us to improve our science and learn how to protect the natural environment on planetary bodies. Small, lightweight detectors like EMS might become standard equipment on future lunar landers.”

With the goal of developing the first long-term presence on the Moon, ESA is joining forces with NASA and other partners on humanity’s return to the Moon. The next ‘Artemis’ generation to experience lunar landings will be an international one and is opening up lunar space exploration to the global population.

Follow the next major milestone in human exploration by taking part in the first-ever online lunar marathon. The French initiative On the Moon Again is hosting 24 hours of talks and lunar observations in English for a global audience. More information and to registration

Credits: The Open University

Europe strengthened its connection to space on Wednesday 27 January, as NASA astronauts Mike Hopkins (white suit with red stripes) and Victor Glover (plain white suit) installed the Columbus KA-band antenna (ColKa) outside ESA’s Columbus laboratory on the International Space Station.

This antenna will create an additional bi-directional KA-band data transmission for the Space Station, providing a direct link between the Columbus laboratory and Europe, for researchers and astronauts, at home broadband speeds.

Victor transported the fridge-sized unit from the airlock to the worksite on the Canadarm2 robotic arm, with assistance from NASA astronaut Kate Rubins and JAXA astronaut Soichi Noguchi inside the Station. There, he and Mike set to work unscrewing and screwing bolts to hold the antenna in place and routing cables for power and data, guided by the voice of ESA astronaut Andreas Mogensen from NASA’s mission control centre in Houston.

Mike and Victor also connected power cables for external commercial research platform Bartolomeo, located outside Columbus. This connection will be continued during a future spacewalk.

Credits: NASA

This image, captured on 2 April 2021 by the Copernicus Sentinel-2 mission, shows the latest activity in Italy’s Mount Etna. The image has been processed using the mission’s shortwave-infrared band to show the ongoing activity in the crater. Smoke plumes can be seen blowing eastwards towards the town of Giarre.

Read full story: Satellites monitor Mount Etna’s unpredictable behaviour

Credits: contains modified Copernicus Sentinel data (2021), processed by ESA, CC BY-SA 3.0 IGO

This spectacular image of Earth was captured by the Meteosat Second Generation series of missions on 23 March 2022.

Satellites provide essential information for everyday applications, improving agricultural practices, to help when disasters strike, and thanks to the Meteosat series, provide crucial data for weather forecasting.

Given that extreme weather and severe storms pose significant and increasing hazards to society, the Meteosat satellites provide detailed, full disc imagery over Europe and Africa every 15 minutes and rapid scan imagery over Europe every five minutes.

This imagery is crucial for nowcasting, which is about detecting rapidly high impact weather and predicting its evolution a few hours ahead, in support of the safety of life and property. These observations are also used for weather forecasting and climate monitoring.

The Meteosat missions have guaranteed the continuous flow of data for weather forecasting since 1977, and later this year, we will soon begin a new era in weather and climate monitoring with Meteosat Third Generation (MTG).

The third generation will not only guarantee the continuity of data for weather forecasting, but offer significant enhancement of the current imager capabilities, an all-new infrared sounding capability and real-time lightning imaging for early detection of severe storms as they develop.

For the overall MTG mission two types of satellite are being developed; the Imaging satellite (MTG-I) and the Sounding Satellite (MTG-S). MTG-I1 is currently at Thales Alenia Space’s facilities in Cannes, France, undergoing an extensive testing campaign to ensure that the satellite will survive the rigours of the launch and the hostile environment of space.

This image is also featured on the Earth from Space video programme.

Credits: EUMETSAT/ESA

This image of the Cartwheel and its companion galaxies is a composite from the NASA/ESA/CSA James Webb Space Telescope's Near-Infrared Camera (NIRCam) and Mid-Infrared Instrument (MIRI), which reveals details that are difficult to see in the individual images alone.

This galaxy formed as the result of a high-speed collision that occurred about 400 million years ago. The Cartwheel is composed of two rings, a bright inner ring and a colourful outer ring. Both rings expand outward from the centre of the collision like shockwaves.

However, despite the impact, much of the character of the large, spiral galaxy that existed before the collision remains, including its rotating arms. This leads to the “spokes” that inspired the name of the Cartwheel Galaxy, which are the bright red streaks seen between the inner and outer rings. These brilliant red hues, located not only throughout the Cartwheel, but also the companion spiral galaxy at the top left, are caused by glowing, hydrocarbon-rich dust.

In this near- and mid-infrared composite image, MIRI data are coloured red while NIRCam data are coloured blue, orange, and yellow. Amidst the red swirls of dust, there are many individual blue dots, which represent individual stars or pockets of star formation. NIRCam also defines the difference between the older star populations and dense dust in the core and the younger star populations outside of it.

Webb’s observations capture Cartwheel in a very transitory stage. The form that the Cartwheel Galaxy will eventually take, given these two competing forces, is still a mystery. However, this snapshot provides perspective on what happened to the galaxy in the past and what it will do in the future.

NIRCam was built by a team at the University of Arizona and Lockheed Martin’s Advanced Technology Center.

MIRI was contributed by ESA and NASA, with the instrument designed and built by a consortium of nationally funded European Institutes (the MIRI European Consortium) in partnership with JPL and the University of Arizona.

More information

Credits: NASA, ESA, CSA, STScI

Stretches of land across New South Wales, Australia, have been hit with torrential rain leading to record-breaking floods. The heavy rainfall has caused dams to spill over, rives to burst their banks and thousands of people forced to evacuate their homes. Data from the Copernicus Sentinel-1 mission are being used to map flooded areas to help relief efforts.

This radar image uses information from two separate images captured by the Sentinel-1 mission on 7 and 19 March highlighting flooded areas in dark blue and urban areas in light grey. Many of these areas affected by the record-breaking floods were ravaged by wildfires during Australia’s bushfire season in 2019. Large swaths of bushland and grazing country were scorched black by the blazes, with patches of burned land visible in light brown in the image.

Images acquired before and after flooding offer immediate information on the extent of inundation and support assessments of property and environmental damage. Copernicus Sentinel-1’s radar ability to ‘see’ through clouds and rain, and in darkness, makes it particularly useful for monitoring floods.

Data from the Copernicus Sentinel-1 mission have been used by the Copernicus Emergency Mapping Service, activated on 20 March, to map the flooded areas. The service provides information for emergency response to different types of disasters, including meteorological hazards, geophysical hazards, deliberate and accidental man-made disasters and other humanitarian disasters, as well as prevention, preparedness, response and recovery activities.

Credits: Contains modified Copernicus Sentinel data (2021), processed by ESA/NASA MODIS

This sweeping view along a rusty red ridge and into a crater showcases the exquisite beauty of icy, layered terrain in the south polar region on Mars.

The High Resolution Stereo Imaging camera onboard ESA’s Mars Express captured this frosty scene in the Ultimi Scopuli region near the south pole of Mars on 19 May 2022. At this time it was southern hemisphere spring and ice was starting to retreat. Dark dunes began to peak through the frost and elevated terrain appears ice-free.

Read more

Credits: ESA/DLR/FU Berlin, CC BY-SA 3.0 IGO

It can be hard to appreciate that a human-made, football-pitch-sized spacecraft is orbiting 400 km above our heads, but there it is.

The jewel of human cooperation and ingenuity that is the International Space Station shines brightly in this image captured by ESA astronaut Thomas Pesquet from the SpaceX Crew Dragon Endeavour.

Crew-2 got these amazing views during a flyaround of the orbiting lab after undocking from the Harmony module on 8 November, before their return to Earth.

Since this image was taken, there has even been a new addition in the form of the Russian Node Module, known as Prichal. The final Russian module planned for the Station, it is a spherical node attached to the Russian segment with six docking ports for future Progress and Soyuz arrivals.

A collaboration between five space agencies, the Station has become a symbol of peaceful international cooperation for 23 years now. It represents the best of our space engineering capabilities as well as humankind’s pursuit of scientific knowledge and exploration.

By any standards, it is an incredible piece of spacecraft engineering. Weighing 420 tonnes, it travels in low-Earth orbit at more than 27 000 km/hour, circling Earth approximately 16 times every day.

Crew members conduct scientific research in microgravity at facilities such as ESA’s Columbus module. Some of these experiments and tests are preparing the way for human exploration of the Moon and beyond. But the Station also provides a unique view of Earth, while its science benefits life on our planet.

Current ESA astronaut in residence is Matthias Maurer, a first-time flier spending around six-months in orbit for his Cosmic Kiss mission. Matthias will continue to support a wide range of European and international science experiments and technological research on the Station before handing off to the next ESA astronaut to fly, Samantha Cristoforetti.

Follow Matthias’s mission on the Cosmic Kiss page.

Credits: ESA/NASA-T. Pesquet

In a peninsula far, far away, a laser shoots into the sky to study the Antarctic atmosphere at Concordia research station.

The Light Detection and Ranging instrument, or LIDAR, is a remote sensing technique that uses light to study an object.

A pulsed laser beam is aimed at the target and properties of the resulting scattered light are recorded by sensors. Using these measurements, researchers collect information about the atmosphere, including density, temperature, wind speed, cloud formation and aerosol particles.

LIDAR and SONAR (sonic detection and ranging) instruments help monitor the Atmospheric Boundary Layer, the 1 km thick bottom layer of the troposphere where changes on Earth’s surface strongly influence temperature, moisture and wind.

These changes to Earth’s surface are largely caused by human activity. Increased greenhouse gas emissions are raising temperatures and the release of chlorofluorocarbons is thinning the ozone layer, particularly in the Polar Regions.

The station operates two LIDAR instruments. The one imaged is the smaller of the two, located 500 m south of the station. A laser beam is emitted daily for one minute every five minutes during the winter period.

Atmospheric physics and chemistry is one field of research undertaken at Concordia to assess the Antarctic climate and overall climate change.

Concordia also runs biomedical studies as an analogue for space exploration. Each year ESA sponsors a research doctor to continue studies on the psychological, physiological and social effects of living in an isolated, confined and extreme environment.

Read more about studies at Concordia on the blog.

Credits: ESA/IPEV/PNRA–S. Thoolen

Cassiopeia A (Cas A) is a supernova remnant located about 11,000 light-years from Earth in the constellation Cassiopeia. It spans approximately 10 light-years. This new image uses data from Webb’s Mid-Infrared Instrument (MIRI) to reveal Cas A in a new light.

On the remnant’s exterior, particularly at the top and left, lie curtains of material appearing orange and red due to emission from warm dust. This marks where ejected material from the exploded star is ramming into surrounding circumstellar material.

Interior to this outer shell lie mottled filaments of bright pink studded with clumps and knots. This represents material from the star itself, and likely shines due to a mix of various heavy elements and dust emission. The stellar material can also be seen as fainter wisps near the cavity’s interior.

A loop represented in green extends across the right side of the central cavity. Its shape and complexity are unexpected and challenging for scientists to understand.

This image combines various filters with the colour red assigned to 25.5 microns (F2550W), orange-red to 21 microns (F2100W), orange to 18 microns (F1800W), yellow to 12.8 microns (F1280W), green to 11.3 microns (F1130W), cyan to 10 microns (F1000W), light blue to 7.7 microns (F770W), and blue to 5.6 microns (F560W). The data comes from the general observer program 1947.

[Image description: A roughly square image is rotated clockwise about 45 degrees. Within the image is a circular-shaped nebula with complex structure. On the circle’s exterior lie curtains of material glowing orange. Interior to this outer shell lies a ring of mottled filaments of bright pink studded with clumps and knots. At center right, a greenish loop extends from the right side of the ring into the central cavity. Translucent wisps of blue, green, and red appear throughout the image.]

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Credits: NASA, ESA, CSA, D. Milisavljevic (Purdue University), T. Temim (Princeton University), I. De Looze (UGent), J. DePasquale (STScI)

This striking image features a relatively rare celestial phenomenon known as a Herbig–Haro object. This particular Herbig–Haro object is named HH111, and was imaged by Hubble’s Wide Field Camera 3 (WFC3). These spectacular objects are formed under very specific circumstances. Newly formed stars are often very active, and in some cases they expel very narrow jets of rapidly moving ionised gas — gas that is so hot that its molecules and atoms have lost their electrons, making the gas highly charged. The streams of ionised gas then collide with the clouds of gas and dust surrounding newly-formed stars at speeds of hundreds of kilometres per second. It is these energetic collisions that create Herbig–Haro objects such as HH111.

WFC3 takes images at optical and infrared wavelengths, which means that it observes objects at a wavelength range similar to the range that human eyes are sensitive to (optical) and a range of wavelengths that are slightly too long to be detected by human eyes (infrared). Herbig–Haro objects actually release a lot of light at optical wavelengths, but they are difficult to observe because their surrounding dust and gas absorb much of the visible light. Therefore, the WFC3’s ability to observe at infrared wavelengths — where observations are not as affected by gas and dust— is crucial to observing Herbo–Haro objects successfully.

Credits: ESA/Hubble & NASA, B. Nisini; CC BY 4.0

The planet Saturn is easily recognizable for its opulent ring system that can easily be seen through a small telescope. Astronomers have now found that the rings are not as placid as they look: a rain of icy particles is affecting the giant planet's weather. It took observations of Saturn from the ESA/NASA Hubble Space Telescope and the retired NASA/ESA/ASI Cassini probe, in addition to the Voyager 1 and 2 spacecraft and the retired International Ultraviolet Explorer mission, to pull it all together.

The telltale evidence is an excess of ultraviolet radiation, seen as a spectral line of hot hydrogen in Saturn's atmosphere. The most feasible explanation is heating caused by icy ring particles raining down onto Saturn's atmosphere. This rain could be due to the impact of micrometeorites, solar wind particle bombardment, solar ultraviolet radiation, or electromagnetic forces picking up electrically charged dust.

A new study pulled together archival ultraviolet-light (UV) observations from four space missions that studied Saturn. This included observations from the two Voyager probes that flew by Saturn in the 1980s and measured the UV excess — at the time, astronomers dismissed the measurements as noise in the detectors. The Cassini mission, which arrived at Saturn in 2004, also collected UV data on the atmosphere over several years, and additional data came from the International Ultraviolet Explorer, launched in 1978, and from Hubble.

But the lingering question was whether all the data could be illusory, or instead reflected a true phenomenon on Saturn. The key to assembling the jigsaw puzzle came in the decision to use measurements from Hubble's Space Telescope Imaging Spectrograph (STIS). Its precision observations of Saturn were used to calibrate the archival UV data from all four other space missions. Four decades of UV data cover multiple solar cycles and help astronomers study the Sun's seasonal effects on Saturn.

By bringing all the diverse data together and calibrating it, it was determined that there is no seasonal difference to the level of UV radiation. The unexpected interaction between the rings and the upper atmosphere is now being investigated in depth, to define new diagnostic tools for estimating if distant exoplanets have extended, Saturn-like ring systems.

[Image description: A close-up image of the planet Saturn in ultraviolet light. The planet is coloured in shades of blue. It is tilted at a forty-five degree angle, and inclined towards the viewer so that its rings are visible; they are only slightly brighter than the black background.]

Credits: ESA/Hubble, NASA & L. Ben-Jaffel; CC BY 4.0

The heavy snowfall that hit Spain a few days ago still lies heavy across much of the country as this Copernicus Sentinel-3 satellite image shows.

While the idea of snuggling under a blanket in the cold winter months is very appealing, the blanket that covers half of Spain is not remotely comforting. This satellite image, captured on 12 January at 11:40 CET, shows how much of the country is still facing hazardous conditions following the snow that fell at the weekend – the heaviest snowfall the country has had in five decades.

Storm Filomena hit Spain over the weekend, covering a large part of the country in thick snow. Madrid one of the worst affected areas (see satellite image), was brought to a standstill with the airport having to be closed, trains cancelled and roads blocked.

People in central Spain are struggling as a deep freeze follows the heavy snow. Yesterday, the temperature plunged to –25°C in Molina de Aragón and Teruel, in mountains east of Madrid – Spain's coldest night for at least 20 years.

Copernicus Sentinel-3 is a two-satellite mission. Each satellite carries a suite of cutting-edge instruments to measure systematically Earth’s oceans, land, ice and atmosphere to monitor and understand large-scale global dynamics. For example, with a swath width of 1270 km, the ocean and land colour instrument, which acquired the two tiles for this image, provides global coverage every two days.

Credits: contains modified Copernicus Sentinel data (2021), processed by ESA, CC BY-SA 3.0 IGO

With giant storms, powerful winds, aurorae, and extreme temperature and pressure conditions, Jupiter has a lot going on. Now, the NASA/ESA/CSA James Webb Space Telescope has captured new images of the planet. Webb’s Jupiter observations will give scientists even more clues to Jupiter’s inner life.

This image comes from the observatory’s Near-Infrared Camera (NIRCam), which has three specialized infrared filters that showcase details of the planet. Since infrared light is invisible to the human eye, the light has been mapped onto the visible spectrum. Generally, the longest wavelengths appear redder and the shortest wavelengths are shown as more blue. Scientists collaborated with citizen scientist Judy Schmidt to translate the Webb data into images.

This image was created from a composite of several images from Webb. Visible aurorae extend to high altitudes above both the northern and southern poles of Jupiter. The aurorae shine in a filter that is mapped to redder colors, which also highlights light reflected from lower clouds and upper hazes. A different filter, mapped to yellows and greens, shows hazes swirling around the northern and southern poles. A third filter, mapped to blues, showcases light that is reflected from a deeper main cloud. The Great Red Spot, a famous storm so big it could swallow Earth, appears white in these views, as do other clouds, because they are reflecting a lot of sunlight.

For a widefield view, click here.

For an annotated widefield view, click here.

Credits: NASA, ESA, Jupiter ERS Team; image processing by Ricardo Hueso (UPV/EHU) and Judy Schmidt

Saturn’s storm are sights to behold. Unlike other planets in the Solar System, the ringed planet seems to store up huge amounts of energy over multiple Earth decades and then release it all at once in the form of a swirling and chaotic lightning storm.

Scientists are unsure why and how the planet behaves this way, but these massive storms occur roughly once every Saturnian year – or once every 30 Earth years – and are known as Great White Spots.

The Great White Spot pictured here, also named the Great Northern Storm, was the largest and most intense storm that the international Cassini mission ever observed on Saturn. It began in late 2010 and lasted for months, but affected the clouds, temperatures and composition of the atmosphere for more than three years.

This true-colour view from Cassini was taken on 25 February 2011, roughly 12 weeks after the storm began, and shows the turbulent patterns within the storm. There appear to be two bands of storm, one further north and brighter than the other. In fact, the storm has thundered its way around the planet and caught up with itself. Some of the cloud south and west of the storm head can be seen tinged blue as it interacts with other currents in the atmosphere, while the storm head swirls with white and yellow as it heads westward to overtake its subtler tail.

It was a lucky coincidence that Cassini happened to be orbiting Saturn during the storm, offering an unprecedented opportunity to study the gas giant’s turbulent weather and climate patterns. Recently, Cassini found this storm to have been so immense and powerful that it was able to disturb the atmosphere at the planet’s equator some tens of thousands of kilometres away.

This disruption of the long-term, cyclical, continuing atmospheric patterns at mid-latitudes (dubbed informally by some as the planet’s ‘heartbeat’), is thought to be due ‘teleconnection’, which we also observe on Earth – when distant events within a climate system are somehow connected and can influence one another significantly.

This image combines red, green and blue filtered images from Cassini’s wide-angle camera to create a real-colour view. These images were taken at a distance of 2.2 million km from Saturn looking towards the sunlit side of the rings from just above the ring plane, and have a scale of 129 km per pixel.

The Cassini mission is a cooperative project of NASA, ESA and Italy’s ASI space agency. After 13 years of pioneering observations, Cassini ended its mission in spectacular fashion on 15 September 2017, plunging through the planet’s inner rings and atmosphere and breaking contact forever.

Credits: NASA/JPL-Caltech/SSI

Northwest Greenland is featured in this icy image captured by the Copernicus Sentinel-3 mission.

Lying in the North Atlantic Ocean, Greenland is the world’s largest island and is home to the second largest ice sheet after Antarctica. Greenland’s ice sheet covers more than 1.7 million sq km and covers most of the island.

Ice sheets form in areas where snow that falls in winter does not melt entirely over the summer. Over thousands of years, layers of snow pile up into thick masses of ice, growing thicker and denser as the new snow and ice layers compress the older layers.

Ice sheets are constantly in motion. Near the coast, most of the ice moves through relatively fast-moving outlets called ice streams, glaciers and ice shelves.

In the top centre of this image, captured on 29 July 2019, the Petermann glacier is visible. Petermann is one of the largest glaciers connecting the Greenland ice sheet with the Arctic Ocean. Upon reaching the sea, a number of these large outlet glaciers extend into the water with a floating ‘ice tongue’. Icebergs occasionally break or ‘calve’ off these tongues.

In this image, sea ice and icebergs can be seen in the Nares Strait – the waterway between Greenland and Canada’s Ellesmere Island, visible top left in the image.

On the tip of Ellesmere Island lies Alert – the northernmost known settlement in the world. Inhabited mainly by military and scientific personnel on rotation, Alert is about 800 km from the closest community, which is roughly the same distance from Alert to the North Pole.

Scientists have used data from Earth-observing satellites to monitor Greenland’s ice sheet. According to a recent study, both Greenland and Antarctica are losing mass six times faster than they were in 1990s. Between 1992 and 2017, Greenland lost 3.8 trillion tonnes of ice – corresponding to around 10 mm contribution to global sea-level rise.

Melting ice sheets caused by rising temperatures and the subsequent rising of sea levels is a devastating consequence of climate change, especially for low-lying coastal areas. The continued satellite observations of the Greenland ice sheet are critical in understanding whether ice mass loss will continue to accelerate and the full implications of this anticipated change.

This image is also featured on the Earth from Space video programme.

Credits: contains modified Copernicus Sentinel data (2019), processed by ESA, CC BY-SA 3.0 IGO

Just in time for the festive season, this new Picture of the Week from the NASA/ESA Hubble Space Telescope features a glistening scene in holiday red. This image shows a small region of the well-known nebula Westerhout 5, which lies about 7000 light-years from Earth. Suffused with bright red light, this luminous image hosts a variety of interesting features, including a free-floating Evaporating Gaseous Globule (frEGG). The frEGG in this image is the small tadpole-shaped dark region in the upper centre-left. This buoyant-looking bubble is lumbered with two rather uninspiring names — [KAG2008] globule 13 and J025838.6+604259.

FrEGGs are a particular class of Evaporating Gaseous Globules (EGGs). Both frEGGs and EGGs are regions of gas that are sufficiently dense that they photoevaporate less easily than the less compact gas surrounding them. Photoevaporation occurs when gas is ionised and dispersed away by an intense source of radiation — typically young, hot stars releasing vast amounts of ultraviolet light. EGGs were only identified fairly recently, most notably at the tips of the Pillars of Creation, which were captured by Hubble in iconic images released in 1995. FrEGGs were classified even more recently, and are distinguished from EGGs by being detached and having a distinct ‘head-tail’ shape. FrEGGs and EGGs are of particular interest because their density makes it more difficult for intense UV radiation, found in regions rich in young stars, to penetrate them. Their relative opacity means that the gas within them is protected from ionisation and photoevaporation. This is thought to be important for the formation of protostars, and it is predicted that many FrEGGs and EGGs will play host to the birth of new stars.

The frEGG in this image is a dark spot in the sea of red light. The red colour is caused by a particular type of light emission known as H-alpha emission. This occurs when a very energetic electron within a hydrogen atom loses a set amount of its energy, causing the electron to become less energetic and this distinctive red light to be released.

[Image description: The background is filled with bright orange-red clouds of varying density. Towards the top-left several large, pale blue stars with prominent cross-shaped spikes are scattered. A small, tadpole-shaped dark patch floats near one of these stars. More of the same dark, dense gas fills the lower-right, resembling black smoke. A bright yellow star and a smaller blue star shine in front of this.]

Credits: ESA/Hubble & NASA, R. Sahai; CC BY 4.0

Geomagnetic activity caused by our star recently created a stir in the skies over Iceland, resulting in the seeming electrification of the night, as captured here by photographer Ollie Taylor.

Unpredictable and temperamental, our Sun blasts intense radiation and colossal amounts of energetic material in every direction, creating the ever-changing conditions in space known as ‘space weather’.

The solar wind is a constant stream of electrons, protons and stripped-down atoms emitted by the Sun, while Coronal Mass Ejections are the Sun’s periodic outbursts of colossal clouds of solar plasma. The most extreme of these events disturb Earth’s protective magnetic field, creating geomagnetic storms at our planet.

Geomagnetic storms can seriously interfere with infrastructure on Earth and in space, and pose a radiation threat to future explorers of the Moon and Mars. It is thought that a solar storm today on the scale of the Carrington event of 1859, would cause billions of euros of damage to satellites, power grids and radio communications.

While extreme solar events can’t be prevented, advance warning can give operators time to act to protect critical infrastructure. ESA’s planned Lagrange mission to monitor the Sun will do just that, feeding data into the European Space Weather Service Network.

From 3-5 March 2019, ESA will be holding a SocialSpace event in Tromsø, Norway, offering participants the chance to learn all about the stunning Aurora and its slightly sinister origins.

Follow @esaoperations and the hashtag #AuroraHunters for all you could want to know about space weather, the aurora and ESA’s plans to protect us from the dangerous outbursts of our Sun.

For more of Ollie’s wonderful photography, visit his website.

Credits: © Ollie Taylor. Used with permission

This whirling, twisting skyscape is an arresting and somewhat intimidating sight – a perfect Halloween Space Science Image of the Week. Jagged lanes in shades of dark and pale green tangle with bright patches of white, creating a knotted spiral somewhat reminiscent of a celestial serpent writhing across the sky, looming ominously over the sleepy town below.

It may look appropriately spooky and otherworldly, but this image shows something that is quite commonplace at Earth’s northern- and southernmost latitudes. The flashes of green in the sky are an aurora, seen when large bursts of energetic atomic particles stream out from the Sun and hit a planet’s atmosphere. These particles filter down through the protective layers surrounding Earth – such as the magnetosphere, the region of space dominated by the magnetic field – and interact with the air particles found below in the atmosphere. Patches of atmosphere subsequently glow brightly and eerily, filling our skies with startling ripples and flashes of colour.

Auroras are often referred to as ‘the northern lights’ (aurora borealis), but they also occur regularly at southern latitudes (aurora australis). They are best seen from regions including Australia, New Zealand, Antarctica and parts of South America (southern), and Canada, Alaska, Scandinavia and Iceland (northern).

The effect is seen only at polar and near-polar latitudes because the charged particles travel in towards Earth along magnetic field lines that meet our planet at its poles.

Auroras are the most visible manifestation of the Sun’s effect on Earth. Since 2000, ESA’s quartet of Cluster satellites has been investigating the complex Sun–Earth connection and has been unravelling the puzzle of how and why auroras form.

This image shows a town in southern Iceland named Selfoss, on the Ölfusá River (visible in the foreground). It was taken by photographer Davide Necchi on 27 August 2015. This particular aurora was linked to a solar storm, which caused an especially large and sudden outpouring of particles into our atmosphere. As a result, the lights were intense and unusually bright, appearing abruptly in the evening sky before it was fully dark. In fact, the aurora was so bright that Davide opted for a relatively short 3 second exposure time, conscious that any longer may cause the brightest parts of the photograph(image) to ‘burn’ or become ‘blown-out’, thus losing detail.

Necchi used a Canon 5D Mark II camera with a 14 mm f2.8 lens. This image had an ISO of 1600, and no filter has been applied. The bright full Moon is also visible in the frame, hanging beneath a layer of cloud.

Credit: D. Necchi (www.davnec.eu)

The globular cluster Terzan 2 in the constellation Scorpio features in this observation from the NASA/ESA Hubble Space Telescope. Globular clusters are stable, tightly gravitationally bound clusters of tens of thousands to millions of stars found in a wide variety of galaxies. The intense gravitational attraction between the closely packed stars gives globular clusters a regular, spherical shape. As a result, images of the hearts of globular clusters, such as this observation of Terzan 2, are crowded with a multitude of glittering stars.

Hubble used both its Advanced Camera for Surveys and its Wide Field Camera 3 in this observation, taking advantage of the complementary capabilities of these instruments. Despite having only one primary mirror, Hubble’s design allows multiple instruments to be used to inspect astronomical objects. Light from distant astronomical objects enters Hubble and is collected by the telescope's 2.4-metre primary mirror; it is then reflected off the secondary mirror into the depths of the telescope, where smaller mirrors can direct light into individual instruments.

Each of the four operational instruments on Hubble is a masterpiece of astronomical engineering in its own right, and contains an intricate array of mirrors and other optical elements to remove any aberrations or optical imperfections from observations, as well as filters which allow astronomers to observe specific wavelength ranges. The mirrors inside each instrument also correct for the slight imperfection of Hubble's primary mirror. The end result is a crystal-clear observation, such as this glittering portrait of Terzan 2.

Credits: ESA/Hubble & NASA, R. Cohen; CC BY 4.0

The arms of the spiral galaxy M74 are studded with rosy pink regions of fresh star formation in this image from the NASA/ESA Hubble Space Telescope. M74 — also known as the Phantom Galaxy — lies around 32 million light-years away from Earth in the constellation Pisces, and is a familiar sight for Hubble.

The beautiful reddish blooms that spread throughout M74 are huge clouds of hydrogen gas which are made to glow by the ultraviolet radiation from hot, young stars embedded within them. These regions — which astronomers refer to as H II regions — mark the location of recent star formation and are an important target for both space- and ground-based telescopes. Hubble’s Advanced Camera for Surveys, which collected the data in this image, even has a filter designed to pick out only this specific red wavelength of light!

The data in this image come from a set of observations exploring the evolution of local spiral galaxies such as M74, which aim to gain insights into the history of star formation in these spirals. To do this astronomers examined star clusters to date the different parts of spiral galaxies, enabling them to understand how the galaxies assembled over time. They also explored the distribution of dust in spiral galaxies; this dust is visible in this image as the dark threads winding along the spiral arms of M74.

Aside from their quest to understand the history of spiral galaxies, astronomers also observed M74 to complement observations from other telescopes. Combining observations of the same object from different telescopes across the electromagnetic spectrum gives astronomers far more insight than observations from a single telescope would. Hubble’s observations also paved the way for future instruments; M74 was one of the first targets of the powerful new NASA/ESA/CSA James Webb Space Telescope.

Credits: ESA/Hubble & NASA, R. Chandar; CC BY 4.0

While appearing as a delicate and light veil draped across the sky, this image from the NASA/ESA Hubble Space Telescope actually depicts a small section of the Cygnus supernova blast wave, located around 2400 light-years away. The name of the supernova remnant comes from its position in the northern constellation of Cygnus (The Swan), where it covers an area 36 times larger than the full moon.

The original supernova explosion blasted apart a dying star about 20 times more massive than our Sun between 10 000 and 20 000 years ago. Since then, the remnant has expanded 60 light-years from its centre. The shockwave marks the outer edge of the supernova remnant and continues to expand at around 350 kilometres per second. The interaction of the ejected material and the low-density interstellar material swept up by the shockwave forms the distinctive veil-like structure seen in this image.

Credits: ESA/Hubble & NASA, W. Blair; CC BY 4.0; Acknowledgement: Leo Shatz

Scattered around an ancient martian river delta, ten tubes lay filled with samples that could help answer if life ever arose on Mars. How many can you spot?

NASA’s Perseverance rover took this selfie looking down at one of 10 sample tubes deployed during the creation of the first sample depot on another world. The camera on the rover’s robotic arm took 59 individual images to build this vermillion view.

It was on the 690th martian day of its mission, or sol, when the rover dropped the tenth and final tube on the Red Planet in an area nicknamed “Three Forks.” The titanium tubes were deposited in a zigzag pattern, with each sample up to 15 meters apart.

These samples, known together as a “sample depot,” will serve as a backup set. The rover has been busy collecting two samples of each rock in the Jezero crater – one that is held within its belly, and a backup sample left on the surface of Mars.

There are two options for the double sample-taking of the Mars Sample Return campaign. Plan A will see the rover delivering the main set of samples directly to a lander with the help of ESA’s Sample Transfer Arm. In case Perseverance is not able to hand the samples over at the end of this decade, there is a Plan B – two small drone helicopters will fetch the tubes set aside on the ground and take them to the lander. The 2.5 metre-long European robot will give a hand to collect them from the ground and transfer them into the container bound for a trip to Earth.

Mission scientists believe that the rock cores part of this depot will give us an overview of the geological processes that took place in the Jezero crater almost four billion years ago. The rover also deposited an atmospheric sample and a “witness” tube, which is used to determine if samples being collected might be contaminated with materials that traveled with the rover from Earth.

For those who worry about the samples being left on their own for nearly a decade, be assured that teams on Earth are recording the precise location of each tube for when the time comes to collect them. And even if martian winds can reach high speeds, they are not as strong as on Earth. The atmosphere on Mars is less dense: about 100 times less than on our planet. Any dust collecting on the tubes will not cover them fully when collection time comes.

To understand the complexity of the tasks ahead, watch this trailer that describes the Mars Sample Return campaign in just two minutes. Stay up-to-date on the latest news with ESA’s blog To Mars and Back.

Credits: NASA/JPL-Caltech/MSSS

Auroras make for great Halloween décor over Earth, though ESA astronaut Thomas Pesquet snapped these green smoky swirls of plasma from the International Space Station in August. Also pictured are the Soyuz MS-18 “Yuri Gagarin” (left) and the new Nauka module (right).

The Station saw quite some aurora activity that month, caused by solar particles colliding with Earth’s atmosphere and producing a stunning light show.

Fast forward to October and space is quite busy.

On 9 October the Sun ejected a violent mass of fast-moving plasma into space that arrived at Earth a few days later. The coronal mass ejection (CME) crashed into our planet’s magnetosphere and once again lit up the sky.

CMEs explode from the Sun, rush through the Solar System and while doing so speed up the solar wind – a stream of charged particles continuously released from the Sun’s upper atmosphere.

While most of the solar wind is blocked by Earth’s protective magnetosphere, some charged particles become trapped in Earth’s magnetic field and flow down to the geomagnetic poles, colliding with the upper atmosphere to create the beautiful Aurora.

While the view outside the Space Station is mesmerising, the astronauts inside are busy with science and prepping for the next crew’s arrival later this month.

Thomas will welcome fellow ESA astronaut Matthias Maurer, currently scheduled to launch to the Space Station on Halloween.

In the meantime, Thomas has taken over command of the Space Station and is busy completing more science ahead of the end of mission Alpha and his return to Earth.

The astronauts have taken up space farming lately, tending to New Mexico Hatch Green Chili peppers in the name of science. A few investigations are looking into different aspects of plant behaviour in microgravity.

Tending to the body via exercise is also standard practice on the Space Station. The crew performed cycles of experiments looking into immersive exercise practices as well as the familiar Grasp experiment on reflexes under microgravity conditions.

Even downtime is ripe for experimentation, with Thomas wearing a headset to bed to track quality of sleep under weightless conditions. Read more about the goings-on in the latest monthly science recap.

Find more stunning imagery and exciting news on the Alpha blog.

Credits: ESA/NASA–T. Pesquet

The Copernicus Sentinel-2 mission takes us over part of the Namib Desert in western Namibia. At 55 million years old, Namib is considered the oldest desert on Earth.

In this image, captured on 27 October 2019, a large portion of the Namib-Naukluft National Park is visible. The park covers an area of almost 50 000 sq km and encompasses part of the Namib Desert and the Naukluft Mountains to the east. Straight, white lines visible in the right of the image are roads that connect the Namib-Naukluft National Park with other parts of Namibia.

The park’s main attraction is Sossusvlei – a large salt and clay pan visible in the centre of the image. The bright white floors of the pan contrasts with the rust-red dunes that surround it.

Sossusvlei acts as an endorheic basin for the Tsauchab River – an ephemeral river flowing from the east. Owing to the dry conditions in the Namib Desert, the river rarely flows this far and the pan usually remains dry most years. In the past, water from the Tsauchab has reached the Atlantic coast a further 60 km away.

The dunes in this area are some of the highest in the world. The tallest, nicknamed ‘big daddy,’ stands at around 325 m. The dunes facing the river valley are called star dunes and are formed from winds blowing in multiple directions, creating long ‘arms’ that point into the valley from both sides.

These dunes contrast with the saffron-coloured dunes visible in the Namib Sand Sea, just south of Soussusvlei. The sand sea consists of two dune seas, one on top of another. The foundation of the ancient sand sea has existed for at least 21 million years, while the younger sand on top has existed for around 5 million years. The dunes here are formed by the transportation of materials from thousands of kilometres away, carried by river, ocean current and wind.

The Namib Sand Sea is the only coastal desert in the world to contain large dune fields influenced by fog – the primary source of water for the Namib Sand Sea. Haze is visible in the bottom left of the image, the last leftovers of fog coming from the Atlantic Ocean.

Copernicus Sentinel-2 is a two-satellite mission to supply the coverage and data delivery needed for Europe’s Copernicus programme.

This image is featured on the Earth from Space video programme.

Credits: contains modified Copernicus Sentinel data (2019), processed by ESA, CC BY-SA 3.0 IGO

A spectacular trio of merging galaxies in the constellation Boötes takes centre stage in this image from the NASA/ESA Hubble Space Telescope. These three galaxies are set on a collision course and will eventually merge into a single larger galaxy, distorting one another’s spiral structure through mutual gravitational interaction in the process. An unrelated foreground galaxy appears to float serenely alongside the collision, and the smudged shapes of much more distant galaxies are visible in the background.

This colliding trio — known to astronomers as SDSSCGB 10189 — is a relatively rare combination of three large star-forming galaxies lying within only 50 000 light-years of one another. While that might sound like a safe distance, for galaxies this makes them extremely close neighbours! Our own galactic neighbours are much further away; Andromeda, the nearest large galaxy to the Milky Way, is more than 2.5 million light-years away from Earth.

This observation was designed to help astronomers understand the origin of the largest, most massive galaxies in the universe. These galactic behemoths are called Brightest Cluster Galaxies (BCGs) and — as the name suggests — are defined as the brightest galaxies in any given galaxy cluster. Astronomers suspect that BCGs form through the merger of large, gas-rich galaxies like the ones in this image. They turned to Hubble’s Wide Field Camera 3 and Advanced Camera for Surveys to investigate this galactic trio in painstaking detail, hoping to shed light on the formation of the Universe’s most massive galaxies.

[Image description: Three galaxies stand together just right of centre. They are close enough that they appear to be merging into one. Their shapes are distorted, with strands of gas and dust running between them. Each is emitting a lot of light. Further to the left is an unconnected, dimmer spiral galaxy. The background is dark, with a few smaller, dim and faint galaxies and a couple of stars.]

Credits: ESA/Hubble & NASA, M. Sun; CC BY 4.0

The two interacting galaxies making up the pair known as Arp-Madore 608-333 seem to float side by side in this image from the NASA/ESA Hubble Space Telescope. Though they appear serene and unperturbed, the two are subtly warping one another through a mutual gravitational interaction that is disrupting and distorting both galaxies. This drawn-out galactic interaction was captured by Hubble’s Advanced Camera for Surveys.

The interacting galaxies in Arp-Madore 608-333 were captured as part of an effort to build up an archive of interesting targets for more detailed future study with Hubble, ground-based telescopes, and the NASA/ESA/CSA James Webb Space Telescope. To build up this archive, astronomers scoured existing astronomical catalogues for a list of targets spread throughout the night sky. By so doing, they hoped to include objects that had already been identified as interesting and that would be easy for Hubble to observe no matter which direction it was pointing.

Deciding how to award Hubble observing time is a drawn-out, competitive and difficult process, and the observations are allocated so as to use every last second of Hubble time available. However, there is a small but persistent fraction of time — around 2–3% — that goes unused as Hubble turns to point at new targets. Snapshot programmes, such as the one which captured Arp-Madore 608-333, exist to fill this gap and take advantage of the moments between longer observations. As well as creating beautiful images such as this, these snapshot programs enable astronomers to gather as much data as possible with Hubble.

Credits: ESA/Hubble & NASA, Dark Energy Survey/DOE/FNAL/DECam/CTIO/NOIRLab/NSF/AURA, J. Dalcanton; CC BY 4.0

The Tarso Toussidé volcanic massif is featured in this false-colour composite image captured by the Copernicus Sentinel-2 mission.

Tarso Toussidé, capped by the Toussidé (potentially active) stratovolcano, is located in the western end of the Tibesti Mountains, in Chad. With an elevation of 3265 m above sea level, Toussidé is the second highest peak in Tibesti, after Emi Koussi.

Toussidé has undergone a number of eruptions and lava flows, with the lava reaching lengths of 25 km and covering an area of 200 sq km, appearing to have ‘stained’ the ground in the process. The volcano ejected tephra, fragments of rock and volcano glass, lava and ash. In the middle of the field lies Pic Toussidé, a lava dome which can be seen poking out of the caldera.

Toussidé is said to be amongst the youngest volcanoes in Tibesti. A large number of fumaroles (openings in or near a volcano through which gases emerge) are active on its summit, exhaling mostly water vapour at temperatures of 40–60 °C – suggesting it is the only active Tibesti volcano.

Just next to Toussidé, in the far-right of the image, lies the Trou au Natron caldera, which sits at an elevation of around 2450 m. A number of volcanic cones sit on the floor of the caldera, with numerous vents and hot springs on the caldera’s floor emitting hot steam.

Much of the surface of the caldera is lined with a white crust of salts, including sodium carbonite. These crusts are usually formed when mineral-rich steam is emitted from small vents on the crater’s floor, and when this evaporates in the heat, the minerals are left behind.

The caldera has an irregular diameter of around 6-8 km and is up to 1000 m deep, and is said to have been filled by a freshwater lake during the last glacial maximum.

In the left of the image, the red shows sparse vegetation along the ephemeral creeks.

Satellite imagery is a practical way to study remote areas such as the volcanic regions in the Tibesti Mountain Range. The Copernicus Sentinel-2 mission carries a multispectral imager with 13 spectral bands and has a wide swath coverage, delivering data on Earth’s land every five days.

This image, acquired on 21 September 2019, is also featured on the Earth from Space video programme.

Credits:

contains modified Copernicus Sentinel data (2019), processed by ESA, CC BY-SA 3.0 IGO

This oblique perspective view of part of Mars’ informally named Holden Basin was generated from the digital terrain model and the nadir and colour channels of the High Resolution Stereo Camera on ESA’s Mars Express.

Read more

Credits: ESA/DLR/FU Berlin, CC BY-SA 3.0 IGO

The peculiar spiral galaxy ESO 415-19, which lies around 450 million light-years away, stretches lazily across this image from the NASA/ESA Hubble Space Telescope. While the centre of this object resembles a regular spiral galaxy, long streams of stars stretch out from the galactic core like bizarrely elongated spiral arms. These are tidal streams caused by some chance interaction in the galaxy’s past, and give ESO 415-19 a distinctly peculiar appearance.

ESO 415-19’s peculiarity made it a great target for Hubble. This observation comes from an ongoing campaign to explore the Arp Atlas of Peculiar Galaxies, a menagerie of some of the weirdest and most wonderful galaxies that the Universe has to offer. These galaxies range from bizarre lonesome galaxies to spectacularly interacting galaxy pairs, triplets, and even quintets. These space oddities are spread throughout the night sky, which means that Hubble can spare a moment to observe them as it moves between other observational targets.

This particular observation lies in a part of the night sky contained by the Fornax constellation. This constellation was also the site of a particularly important Hubble observation; the Hubble Ultra Deep Field. Creating the Ultra Deep Field required almost a million seconds of Hubble time, and captured nearly 10,000 galaxies of various ages, sizes, shapes, and colours. Just as climate scientists can recreate the planet’s atmospheric history from ice cores, astronomers can use deep field observations to explore slices of the Universe’s history from the present all the way to when the Universe was only 800 million years old!

[Image description: A spiral galaxy. It has a bright core with patches of dark dust, and fuzzier, dimmer spiral arms in cooler colours, with spots of bright blue. Long, faint tidal streams stretch from the galaxy’s arms: one up to the top of the frame, one curving down to the bottom-left corner. In the top-right there is a smaller, orange elliptical galaxy. The background is studded with many tiny stars and galaxies.]

Credits: ESA/Hubble & NASA, J. Dalcanton, Dark Energy Survey/DOE/FNAL/DECam/CTIO/NOIRLab/NSF/AURA; CC BY 4.0

This stellar whirlpool is a spiral galaxy named NCG 7329, which has been imaged by Hubble’s Wide Field Camera 3 (WFC3). Creating a colourful image such as this one using a telescope such as Hubble is not as straightforward as pointing and clicking a camera. Commercial cameras will typically try to collect as much light of all visible wavelengths as they can, in order to create the most vibrant images possible. In contrast, raw images collected by Hubble are always monochromatic, because astronomers typically want to capture very specific ranges of wavelengths of light at any time, in order to do the best, most accurate science possible. In order to control which wavelengths of light will be collected, Hubble’s cameras are equipped with a wide variety of filters, which only allow certain wavelengths of light to reach the cameras’ CCDs (a CCD is a camera’s light sensor — phone cameras also have CCDs!).

How are the colourful Hubble images possible given that the raw Hubble images are monochromatic? This is accomplished by combining multiple different observations of the same object, obtained using different filters. This image, for example, was processed from Hubble observations made using four different filters, each of which spans a different region of the light spectrum, from the ultraviolet to optical and infrared. Specialised image processors and artists can make informed judgements about which optical colours best correspond to each filter used. They can then colour the images taken using that filter accordingly. Finally, the images taken with different filters are stacked together, and voila! The colourful image of a distant galaxy is complete, with colours as representative of reality as possible.

Credits: ESA/Hubble & NASA, A. Riess et al.; CC BY 4.0