11 December is International Mountain Day and to commemorate this day, the Copernicus Sentinel-2 satellite flies over Mount Everest, the highest mountain on Earth.

Mount Everest is part of a region known as "third pole", since the high-altitude ice fields in this area contain the largest reserve of freshwater outside the polar regions.

With such a large portion of the world’s population dependent on water from these cold heights, changes in the size and flow of these glaciers can bring serious consequences for society by affecting the amount of water arriving downstream. From the vantage point of space, satellites, such as the Copernicus Sentinels, provide essential information to monitor the changing face of Earth’s glaciers, which are typically in remote regions and therefore difficult to monitor systematically from the ground.

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

On 11 March 2022, the James Webb Space Telescope (Webb) team completed the stage of mirror alignment known as "fine phasing". Although there are months to go before Webb ultimately delivers its new view of the cosmos, achieving this milestone means the team is confident that Webb’s first-of-its-kind optical system is working as well as possible.

At this key stage in the commissioning of Webb’s Optical Telescope Element, every optical parameter that has been checked and tested is performing at, or above, expectations. The team also found no critical issues and no measurable contamination or blockages to Webb’s optical path: the observatory is able to successfully gather light from distant objects and deliver it to its instruments without issue. At this stage of Webb’s mirror alignment, each of the primary mirror segments has been adjusted to produce one unified image of the same star using only Webb’s primary imager, the Near-Infrared Camera (NIRCam), and NIRCam has been fully aligned to the observatory's mirrors.

While the purpose of this image was to focus on the bright star at the centre (called 2MASS J17554042+6551277) for alignment evaluation, Webb's optics and NIRCam are so sensitive that galaxies and stars in the background also show up. This image uses a red filter to optimise visual contrast.

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Credits: NASA/STScI

This eerie coloured orb is nothing less than the life-giver of the Solar System. It is the Sun, the prodigious nuclear reactor that sits at the heart of our planetary system and supplies our world with all the light and heat needed for us to exist.

This image was taken by SOHO's (Solar & Heliospheric Observatory) extreme-ultraviolet telescope. This telescope is sensitive to four wavelengths of extreme-ultraviolet light, and the three shortest were used to build this image. Each wavelength has been colour-coded to highlight the different temperatures of gas in the Sun.

Credit: SOHO (ESA & NASA)

Read more about the colours in this image here. 

Resting on the tail of the Great Bear in the constellation of Ursa Major, lies NGC 5585, a spiral galaxy that is more than it appears.

The many stars, and dust and gas clouds that make up NGC 5585, shown here in this Hubble image, contribute only a small fraction of the total mass of the galaxy. As in many galaxies, this discrepancy can be explained by the abundant yet seemingly invisible presence of dark matter.

The stellar disc of the galaxy extends over 35 000 light-years across. When compared with galaxies of a similar shape and size, NGC 5585 stands out by having a notably different composition: Contributing to the total mass of the galaxy, it contains a far higher proportion of dark matter.

Hotspots of star formation can be seen along the galaxy’s faint spiral arms. These regions shine a brilliant blue, contrasting strikingly against the ever-black background of space.

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

Acknowledgement: Gagandeep Anand

This NASA/ESA Hubble Space Telescope image of the asteroid Dimorphos was taken on 19 December 2022, nearly four months after the asteroid was impacted by NASA’s DART (Double Asteroid Redirection Test) mission. Hubble’s sensitivity reveals a few dozen boulders knocked off the asteroid by the force of the collision. These are among the faintest objects Hubble has ever photographed inside the Solar System. The ejected boulders range in size from 1 m to 6.7 m across, based on Hubble photometry. They are drifting away from the asteroid at around 1 km per hour. The discovery yields invaluable insights into the behaviour of a small asteroid when it is hit by a projectile for the purpose of altering its trajectory.

[Image Description: The bright white object at lower left is the asteroid Dimorphos. It has a blue dust tail extending diagonally to the upper right. A cluster of blue dots surrounds the asteroid. These are boulders that were knocked off the asteroid when, on 26 September 2022, NASA deliberately slammed the half-tonne DART impactor spacecraft into the asteroid as a test of what it would take to deflect some future asteroid from hitting Earth. Hubble photographed the slow-moving boulders in December 2022.]

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Credits: NASA, ESA, D. Jewitt (UCLA); CC BY 4.0

An odd-shaped formation of gas and dust at the centre of the Milky Way, captured by the far-infrared cameras on board ESA’s Herschel space observatory. The nearly continuous strip of dense and cold clumps of material forms an infinity symbol, or sideways 8, that is a few hundred light years across. In this image, the strip twists around an invisible axis running roughly from the top left to the bottom right.

The infinity-shaped loop, estimated to have a whopping 30 million solar masses, is made up of dense gas and dust at a temperature of just 15 degrees above absolute zero. Displayed in yellow in the image, it contrasts with warmer, less dense gas and dust from the centre of the Galaxy that appears inside the strip and is coloured in blue. Surrounding the loop is cool gas, painted in red-brownish tones.

The ring and its surroundings harbour a number of star-forming regions and young stars, which stand out in bright-blue colour in the image. The area is part of the Central Molecular Zone, a region at the centre of the Milky Way permeated with molecular clouds, which are ideal sites for star formation.

The Galactic Centre is located almost 30,000 light years away from the Sun, in the direction of the Sagittarius constellation. It is a complex and dynamic place, with emission nebulae and supernova remnants – in addition to star-forming molecular clouds – surrounding the supermassive black hole that sits at our Galaxy’s core. The gas and dust in this region appears mostly dark when viewed through an optical telescope, but it can be seen clearly with Herschel’s instruments.

This image was captured by the Herschel’s PACS (Photodetector Array Camera and Spectrometer) and SPIRE (Spectral and Photometric Imaging REceiver) far-infrared cameras, and it was first published in 2011. Obtained as part of Hi-GAL, the Herschel infrared Galactic Plane Survey, it combines observations at three different wavelengths: 70 microns (blue), 160 microns (green) and 250 microns (red).

Herschel was an ESA space observatory active from 2009 to 2013. At the time of its launch, it had the largest telescope ever sent into space.

Credits: ESA / NASA / JPL-Caltech / Hi-GAL

Space Science image of the week:

Thanks to a quirk of our cosmos, the Moon’s average distance from Earth is just right for it to appear as the same size in the sky as the significantly larger Sun. Once in a while the Moon slides directly between Earth and the Sun such that it appears to cover our star completely, temporarily blocking out its light and creating a total solar eclipse for those along the narrow path cast by the Moon’s shadow.

Next week, on 21 August, observers situated along a 115 km-wide swath stretching from Oregon to South Carolina in the US will be on this path of totality, with peak totality occurring at 18:26 GMT (check here for detailed timings). For up to 2 minutes 40 seconds, observers at a given location will be bathed in an eerie twilight in the middle of the day.

It is not possible to view totality from Europe, although those in the westernmost region may see a partial eclipse before the Sun drops below the horizon at sunset.

A team of astronomers from ESA will be studying the eclipse from the USA and, like many others, hoping that skies will be clear so that they can capture the phenomena visible only during eclipses. These include beads of light shining through gaps in the lunar terrain, and the glittering ‘diamond ring’ effect as the last and first slither of sunlight glints through immediately before and after totality.

They will also aim to image the Sun’s extended atmosphere, the corona, which is visible to the naked eye only during totality when the rest of the Sun’s light is blocked out.

Observations of the corona are business as usual for the ESA/NASA Solar and Heliospheric Observatory, SOHO, which can use a special filter to block the Sun’s light. During Earth’s total eclipse, SOHO will provide important context of the corona and Sun’s activity from its viewpoint in space.

Outside of the path of totality observers will experience a partial eclipse – seeing the Moon appear to take a bite out of the Sun’s disc. This is similar to what our Proba-2 satellite will see – an example is shown in the image presented here, which was taken during the annular eclipse earlier this year. It shows the turbulent solar disc and swirling corona at extreme-ultraviolet wavelengths.

In fact, Proba-2 will see a series of partial eclipses from Earth orbit. Proba-2 orbits Earth about 14.5 times per day, and thanks to the constant change in viewing angle, will dip in and out of the Moon’s shadow several times during the solar eclipse.

In addition, astronauts aboard the International Space Station, including ESA’s Paolo Nespoli, should also be able to see some aspects of the eclipse. From their unique vantage point, they will view partial eclipses and also hope to capture the Moon’s shadow on the surface of our planet.

Follow ESA’s ground-based activities via cesar.esa.int and join the conversation on Twitter with #eclipse2017 and #solareclipse. We’ll keep you posted on our activities – from ground and space – via @esascience.

Remember: never look directly at the Sun, even when partially eclipsed, without proper eye protection such as special solar eclipse glasses, or you risk permanent eye damage.

Credit: ESA/Royal Observatory of Belgium

During spring and summer, as the air warms up and the sun beats down on the Greenland Ice Sheet, melt ponds pop up. Melt ponds are vast pools of open water that form on both sea ice and ice sheets and are visible as turquoise-blue pools of water in this Copernicus Sentinel-2 image.

When snow and ice melts atop glaciers, water flows in channels and streams and collects in depressions on the surface. These melt ponds can speed up the melting of the surrounding ice since they greatly reduce the ice’s ability to reflect sunlight. This can create a positive feedback where an increasing number of melt ponds absorb more heat which causes ice cover to melt even faster. In this image, captured on 29 August 2022, melt ponds in the province of Avannaata can be easily spotted from space as they are usually much darker than the surrounding ice. In some ponds, chunks of ice float atop the pond’s waters.

The bay visible here is Sugar Loaf Bay (an indentation of the northeast Baffin Bay) in the Upernavik Archipelago. The archipelago extends from the northwest coast of Sigguup Nunaa peninsula to the southern end of Melville Bay.

The Greenland Ice Sheet is the largest ice mass in the northern hemisphere. It extends 2220 km north-south with an average thickness of around 1500 m and spans 1100 km at its widest point.

As most of the northern hemisphere baked under a prolonged heatwave this summer, Greenland has been hit with an unusual late-season heatwave and melt event in early September – the kind of melt that usually occurs in the middle of summer.

The first day of September typically marks the end of the Greenland melt season, as the sun moves lower in the sky with temperatures usually cooling. However, at the beginning of September 2022, temperatures began to rise again when a strong air pressure region parked at the southeast edge of Greenland and drew warmer air northwards across Baffin Bay and the west coast of Greenland.

This led to meltwater runoff, the amount of surface water entering the ocean, to increase with its extensive melting contributing to global sea level rise – which impacts the millions of people living in coastal communities.

In a recent paper published in Nature Climate Change, scientists found that major sea-level rise from the melting of the Greenland ice cap is now ‘inevitable’ even if the burning of fossil fuels were to halt overnight. Using satellite observations of Greenland ice loss and ice cap from 2000 to 2019, the team found the losses will lead to a minimum rise of 27 cm regardless of climate change.

Earth observation satellites are key to monitoring ice as they carry instruments that measure changes in the thickness of the ice sheets, fluctuations in the speed of the outlet glaciers and even small changes in Earth’s gravity field caused by melting ice as well as sea-level rise.

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

Credits: contains modified Copernicus Sentinel data (2022), processed by ESA, CC BY-SA 3.0 IGO

Data from more than 1.8 billion stars has been used to create this map of the entire sky. It shows the total brightness and colour of stars observed by ESA’s Gaia satellite and released as part of Gaia’s Early Data Release 3 (Gaia EDR3).

Brighter regions represent denser concentrations of bright stars, while darker regions correspond to patches of the sky where fewer and fainter stars are observed. The colour of the image is obtained by combining the total amount of light with the amount of blue and red light recorded by Gaia in each patch of the sky.

The bright horizontal structure that dominates the image is the plane of our Milky Way galaxy. It is actually a flattened disc seen edge-on that contains most of the galaxy’s stars. In the middle of the image, the Galactic centre appears bright, and thronged with stars.

Darker regions across the Galactic plane correspond to foreground clouds of interstellar gas and dust, which absorb the light of more distant stars. Many of these clouds conceal stellar nurseries where new generations of stars are currently being born.

Dotted across the image are also many globular and open clusters, as well as entire galaxies beyond our own. The two bright objects in the lower right of the image are the Large and Small Magellanic Clouds, two dwarf galaxies orbiting the Milky Way.

Gaia EDR3 was made public on 3 December 2020 and includes the position and brightness of more than 1.8 billion stars, the parallax and proper motion of almost 1.5 billion stars, and the colour of more than 1.5 billion stars. It also includes more than 1.6 million extragalactic sources.

A complementary image showing Gaia's density map of the stars is available here.

Gaia's all-sky colour view is also available in equirectangular projection (suitable for full-dome presentations) here.

Credits: ESA/Gaia/DPAC; CC BY-SA 3.0 IGO. Acknowledgement: A. Moitinho and M. Barros

ESA astronaut Thomas Pesquet snapped this image of Normandy from the International Space Station during his second long-duration mission known as Alpha. He posted it on social media saying "The Space Station always travels from West to East, which is great for taking pictures of my birthplace Normandy. A perfect frame to start the Earth pictures of #MissionAlpha "

Thomas was launched to the International Space Station for his second mission, Alpha, on 23 April 2021. He will spend six months living and working on the orbital outpost where he will support more than 200 international experiments in space.

Follow Thomas and his Mission Alpha on his blog.

Credits: ESA/NASA–T. Pesquet

This image shows the irregular galaxy NGC 6822, which was observed by the Near-InfraRed Camera (NIRCam) and Mid-InfraRed Instrument (MIRI) mounted on the NASA/ESA/CSA James Webb Space Telescope. As their names suggest, NIRCam and MIRI probe different parts of the electromagnetic spectrum. This allows the instruments to observe different components of the same galaxy, with MIRI especially sensitive to its gas-rich regions (the yellow swirls in this image) and NIRCam suitable for observing its densely packed field of stars.

NGC 6822 lies about 1.5 million light-years away, and is the Milky Way’s nearest galactic neighbour that is not one of its satellites. It has a very low metallicity, meaning that it contains very low proportions of elements that are not hydrogen and helium. Metallicity is an absolutely key concept in astronomy, in part because elements other than hydrogen and helium are largely produced by stars over their lifetimes. Therefore, in the very early Universe (before the first generation of stars had been born, lived and died) everything had very low metallicity. This makes contemporary low-metallicity objects (like NGC 6822) objects of interest for understanding how processes such as the evolution of stars and the life cycle of interstellar dust likely occurred in the early Universe. This was the motivation for these observations of NGC 6822 with Webb: to better understand how stars form and how dust evolves in low-metallicity environments.

The study of NGC 6822 has an interesting history that long predates modern investigations with Webb. It was first discovered by E. E. Barnard, who presented his discovery in a very brief paper in 1884 in The Sidereal Messenger: a short-lived but important American monthly astronomical journal that was published between 1882 and 1891. As with many astronomical objects that appeared diffuse with telescopes of the time, NGC 6822 was miscategorised as an "exceedingly faint nebula".

Over the next few years, a series of confusions arose around NGC 6822 over its apparent size, brightness, and even what kind of object it was, because astronomers at the time did not properly account for how different the same object might look with different telescopes. Edwin Hubble, namesake of the NASA/ESA Hubble Space telescope, went on to study NGC 6822 in depth and published a far more detailed paper of his own in 1925. This work was exceptionally important for humanity’s evolving understanding of the Universe, because, in Hubble’s own words: "N.G.C. 6822, [was] the first object definitely assigned to a region outside the galactic system". This paper contributed to solving the debate that was raging amongst astronomers about the extent of the Universe at the time by demonstrating that there were astronomical objects that lay beyond the Milky Way. The study of this galaxy was notably continued by Susan Keyser, who was the first woman to receive a PhD in astronomy from Caltech. Her 1966 thesis remained the most thorough investigation of this galaxy until the 2000s. Now, the study of this key local galaxy is being continued by Webb.

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[Image Description: A dense field of stars with clouds of gas and dust billowing across it. The clouds are patchy and wispy, dense and glowing parts obscuring the centre of the image. Bright galaxies with various shapes and sizes shine through the gas and stars. Some of the star images are a bit larger than the rest, with visible diffraction spikes; two foreground stars are bright in the lower-right corner.]

Credits: ESA

Parts of the Mediterranean and central Europe have experienced extreme temperatures this summer, with wildfires causing devastation in both Turkey and Greece. The blaze on Evia, Greece’s second-largest island, is one of the worst hit with fires having burned down large forested areas, homes and businesses – forcing thousands to evacuate by sea to save their lives.

This false-colour Copernicus Sentinel-2 image was captured yesterday on 11 August, and has been processed in a way that included the near-infrared channel which is usually used to highlight vegetation (visible in bright red). The image shows the extent of the burned area (visible in shades of brown and green) in the northern part of the island which has suffered the most damage, with an estimated 50 000 hectares lost.

The blaze, fuelled by strong winds, began on 3 August and is still ongoing, with hundreds of firefighters currently tackling the flames.

The heatwave has seen some countries record their highest temperature in decades, with the Italian island of Sicily registering 48.8°C, which may be Europe’s hottest temperature on record. Wildfires have also been raging in other parts of Greece, Italy, Albania and Algeria, prompting activations in the Copernicus Emergency Mapping Service. The mapping service uses data from satellites to aid response to disasters such as wildfires and floods.

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

This panorama of the International Space Station is a wider view of what ESA astronaut Luca Parmitano was capturing on camera during the first of a series of historic spacewalks that took place in November 2019.

Author, journalist and researcher Lee Brandon-Cremer created this photo by stitching together three images taken by Luca as he made his way to the worksite during the first Extravehicular Activity or EVA to service the Alpha Magnetic Spectrometer (AMS), the Station’s dark matter detector.

"For every spacewalk there are thousands of images taken. Sometimes a few images jump out at me,” he explains. “One day I realised I could stitch these images together to expand the scene and show what the astronaut sees in a broader sense.”

To create this view, Lee first went looking for images with common points. This proved tricky: of the 1000 or so images he scanned, he found three that could be worked into two expanded photos of the Space Station.

He then joined and lightly edited the images to create a smooth photograph, a technique referred to as “stitching”.

In the final image you can see the white panel radiators that keep the Space Station cool. The spacecraft on the left is a Soyuz. On the right is the Kibo module, with Japanese flag visible. The Space Station is flying to the right in this picture.

Nowadays we are spoiled for space imagery. From satellites circling the Earth and spacecraft taking selfies to astronaut snaps from the International Space Station, there is no shortage of photographs at which to marvel – and they are easy to access.

Aside from the critical role these images play in aiding scientific studies of Earth, the Solar System and outer space, they are important tools for science communication and public engagement.

One advantage of space imagery made public is how it engages citizen scientists and students all over the world. Take two projects as examples:

Cities at Night asks residents to identify major cities at night as seen by astronauts from the Space Station to help map out and combat light pollution. The Climate Detectives school project tasks students with investigating a local climate problem and proposing a solution by studying Earth observation satellite imagery.

For others like Lee, the images are a source of inspiration and creativity.

“It’s truly thrilling for me to recreate these broader views and it makes me wonder how many more unique views like this one captured by Luca are hiding in space agency archives,” Lee adds.

Download the high resolution image in the link above.

Credits: L. Brandon-Cremer

The narrow galaxy elegantly curving around its spherical companion in this image is a fantastic example of a truly strange and very rare phenomenon. This image, taken with the NASA/ESA Hubble Space Telescope, depicts GAL-CLUS-022058s, located in the southern hemisphere constellation of Fornax (The Furnace). GAL-CLUS-022058s is the largest and one of the most complete Einstein rings ever discovered in our Universe. The object has been nicknamed by the Principal Investigator and his team who are studying this Einstein ring as the "Molten Ring", which alludes to its appearance and host constellation.

First theorised to exist by Einstein in his general theory of relativity, this object’s unusual shape can be explained by a process called gravitational lensing, which causes light shining from far away to be bent and pulled by the gravity of an object between its source and the observer. In this case, the light from the background galaxy has been distorted into the curve we see by the gravity of the galaxy cluster sitting in front of it. The near exact alignment of the background galaxy with the central elliptical galaxy of the cluster, seen in the middle of this image, has warped and magnified the image of the background galaxy around itself into an almost perfect ring. The gravity from other galaxies in the cluster is soon to cause additional distortions.

Objects like these are the ideal laboratory in which to research galaxies too faint and distant to otherwise see.

Credits: ESA/Hubble & NASA, S. Jha; CC BY 4.0

Acknowledgement: L. Shatz

Approximately 85 million light-years from Earth, in the constellation of Libra, is the beautiful galaxy NGC 5861, captured here by the NASA/ESA Hubble Space Telescope.

NGC 5861 is an intermediate spiral galaxy. Astronomers classify most galaxies by their morphology. For example, the Milky Way galaxy is a barred spiral galaxy. An intermediate spiral galaxy has a shape lying in between that of a barred spiral galaxy, one that appears to have a central bar-shaped structure, and that of an unbarred spiral galaxy, one without a central bar.

Two supernovae, SN1971D and SN2017erp, have been observed in the galaxy. Supernovae are powerful and luminous explosions that can light up the night sky. The brightest supernova ever recorded was possibly SN 1006. It shone 16 times as bright as Venus from April 30 to May 1, 1006 AD.

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

An aerial image of ESA’s technical heart, the European Space Research and Technology Centre, ESTEC, making it look as if you could pick it up in your hands.

Nestled beside coastal dunes in Noordwijk in the Netherlands, ESTEC is ESA’s largest establishment and hub of Europe’s space efforts. Combining the downward view angle with defocused surrounding terrain, known as ‘tilt-shifting’, makes the entire sprawling complex appear miniaturised.

On the dune side stands the main building, home to ESA laboratories and mission teams, distinguished by an almost 200-m long main corridor. The central white-hued lab building extends forward from it. The small white dome beside it houses ESA’s Large Diameter Centrifuge for high-gravity testing.

To the left of the main building is the restaurant and tower complex built by renowned Dutch architect Aldo van Eyck. On its right can be seen ESTEC’s Test Centre for full-scale testing of satellites, equipped with a suite of simulation facilities to reproduce every aspect of the space environment.

In front of the car park to the left is the three-block T-building, home to ESA’s Galileo team, in the centre stands the Erasmus centre for human spaceflight with the headquarters of ESA’s Technology Transfer and Patent Office beside it.

This photo was taken during a hobby flight by ESA biomedical engineer Arnaud Runge.

Credits: ESA-SJM Photography

This image, captured by the Copernicus Sentinel-2 mission on 10 October, shows the new flow of lava from the volcano erupting on the Spanish island of La Palma.

This Sentinel-2 image has been processed in true colour, using the shortwave infrared channel to highlight the lava flow. The Sentinel-2 mission is based on a constellation of two identical satellites, each carrying an innovative wide swath high-resolution multispectral imager with 13 spectral bands for monitoring changes in Earth’s land and vegetation.

The Volcanology Institute of the Canary Islands (Involcan) stated that the lava flow, with temperatures up to 1240°C, destroyed the few remaining buildings still standing north of the Todoque neighbourhood.

Read full story: La Palma volcano: How satellites help us monitor eruptions

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

ESA astronaut Thomas Pesquet and NASA astronaut Megan MacArthur run sessions on the Pilote experiment proposed by France’s space agency CNES in the European Columbus module of the International Space Station.

Continuing French neuroscience experiments started on the Russian space station Mir, the Pilote experiment evaluates a new way of providing tactile and visual feedback to astronauts when operating robots. Using a virtual reality headset and a haptic joystick can recreate the feeling of pressure and touch when tele-operating a robotic arm.

The results from Pilote will improve the work space on the International Space Station and future spacecraft for lunar and martian missions, where astronauts in orbit could operate rovers on the surface.

Watch a time lapse of the session here.

Over 200 experiments are planned for Thomas and crew, with 40 European ones and 12 new experiments led by CNES.

Read an overall of Thomas’ first month in space

for mission Alpha, which included work on Pilote and other science experiments, organising Dragon cargo spacecraft deliveries, Space Station maintenance, not to mention daily exercise.

Credits: ESA/NASA

This oblique perspective view shows the southern flanks of Ascraeus Mons, the second-tallest volcano on Mars.

Deep, irregular fissures in the martian surface can be seen snaking towards the camera. These are part of a group of features collectively named Ascraeus Chasmata, which encompasses an enormous patch of collapsed terrain over 70 km across. The part shown here formed as strings of circular or near-circular depressions combined and coalesced to form troughs, causing the ground to collapse – a bit like forming a sinkhole.

This image was generated from the digital terrain model and the nadir and colour channels of the High Resolution Stereo Camera on ESA’s Mars Express.

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

The lunar eclipse that took place in the early hours of Monday 21 January kicks off a major year for our satellite. This year marks the 50th anniversary of the Apollo 11 mission, the first crewed landing on the Moon.

After more than four decades, the Moon is again in the spotlight of space agencies worldwide as a destination for both robotic missions and human explorers.

But first, the lunar eclipse.

The phenomenon known as a total lunar eclipse occurs when the Earth passes directly between the Moon and the Sun, hiding the light that illuminates the surface of our satellite.

As the Moon passes through the shadow of Earth it appears in orange and red hues. This is because a small portion of sunlight is refracted by the Earth's atmosphere and mostly red light reaches the Moon.

Many across Europe woke in the early hours to view this phenomenon and shared their images on social media. The images were stunning across the continent, but particularly over Lake Maggiore. This image of the eclipse at totality was taken at 06:23 CET by Alberto Negro.

In collaboration with international partners, ESA is preparing to go forward to the Moon on several missions to be developed over the next few years.

ESA has already delivered a key component to the NASA Orion spacecraft that will take humans back to the Moon. The European Service Module, the powerhouse engine that will propel the spacecraft, is currently undergoing mating and testing with the rest of the spacecraft in the United States.

Moving away from one-shot orbital missions, ESA is also teaming up with international partners on missions to explore the polar regions hand-in-hand with robots, in international cooperation and commercial participation.

Learn more about our closest neighbour in the Solar System in our interactive exploration guide or this new set of infographics.

Credits: Alberto Negro

This Picture of the Week depicts the open star cluster NGC 330, which lies around 180,000 light-years away inside the Small Magellanic Cloud. The cluster — which is in the constellation Tucana (The Toucan) — contains a multitude of stars, many of which are scattered across this striking image.

Pictures of the Week from the NASA/ESA Hubble Space Telescope show us something new about the Universe. This image, however, also contains clues about the inner workings of Hubble itself. The criss-cross patterns surrounding the stars in this image — known as diffraction spikes — were created when starlight interacted with the four thin vanes supporting Hubble’s secondary mirror.

As star clusters form from a single primordial cloud of gas and dust, all the stars they contain are roughly the same age. This makes them useful natural laboratories for astronomers to learn how stars form and evolve. This image uses observations from Hubble’s Wide Field Camera 3, and incorporates data from two very different astronomical investigations. The first aimed to understand why stars in star clusters appear to evolve differently from stars elsewhere, a peculiarity first observed by the Hubble Space Telescope. The second aimed to determine how large stars can be before they become doomed to end their lives in cataclysmic supernova explosions.

Credits: ESA/Hubble & NASA, J. Kalirai, A. Milone; CC BY 4.0

This image from ESA’s Mars Express shows Korolev crater, an 82-kilometre-across feature found in the northern lowlands of Mars.

This oblique perspective view was generated using a digital terrain model and Mars Express data gathered over orbits 18042 (captured on 4 April 2018), 5726, 5692, 5654, and 1412. The crater itself is centred at 165° E, 73° N on the martian surface. The image has aresolution of roughly 21 metres per pixel.

This image was created using data from the nadir and colour channels of the High Resolution Stereo Camera (HRSC). The nadir channel is aligned perpendicular to the surface of Mars, as if looking straight down at the surface.

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

The image, taken on 27 April 2020 and centred at 52.3°S, 351.8°E, shows part of an impact crater located inside the larger Green Crater in the Argyre quadrangle in the southern hemisphere of Mars.

The image reveals an almost black dune field on the right, surrounded by red soils that are partially covered with bright white ice. Gullies, also partially covered with ice, are visible in the crater wall in the centre of the image. Scientists are currently investigating the relationship between this seasonal ice and the presence of the gullies. The image was taken just after the spring equinox in the southern hemisphere of Mars, when the southernmost part of the crater (to the right) was almost completely free of ice while the northern part (centre) was still partially covered. The southern crater wall has had a longer exposure to the Sun (like on Earth equator-facing slopes receive more sunlight), so the ice in this area recedes faster.

Credits: ESA/ExoMars/CaSSIS

The NASA/ESA Hubble Space Telescope sees galaxies of all shapes, sizes, brightnesses, and orientations in the cosmos. Sometimes, the telescope gazes at a galaxy oriented sideways — as shown here. The spiral galaxy featured in this Picture of the Week is called NGC 3717, and it is located about 60 million light-years away in the constellation of Hydra (The Sea Serpent).

Seeing a spiral almost in profile, as Hubble has here, can provide a vivid sense of its three-dimensional shape. Through most of their expanse, spiral galaxies are shaped like a thin pancake. At their cores, though, they have bright, spherical, star-filled bulges that extend above and below this disc, giving these galaxies a shape somewhat like that of a flying saucer when they are seen edgeon.

NGC 3717 is not captured perfectly edge-on in this image; the nearer part of the galaxy is tilted ever so slightly down, and the far side tilted up. This angle affords a view across the disc and the central bulge (of which only one side is visible).

Credits: ESA/Hubble & NASA, D. Rosario; CC BY 4.0

Astronomers have caught a rare glimpse of a rapidly fading shroud of gas around an aging star. Archival data from the NASA/ESA Hubble Space Telescope reveal that the nebula Hen 3-1357, nicknamed the Stingray nebula, has faded precipitously over just the past two decades. Witnessing such a swift rate of change in a planetary nebula is exceedingly without precedent, researchers say.

Even though the Universe is constantly changing, most processes are too slow to be observed within a human lifespan. However, the Stingray Nebula is now offering scientists a special opportunity to observe a system’s evolution in real time.

Images captured by Hubble in 2016, when compared to Hubble images taken in 1996, show a nebula that has drastically dimmed in brightness and changed shape. Bright blue shells of gas near the centre of the nebula have all but disappeared, and the wavy edges that earned this nebula its aquatic-themed name are virtually gone. The young nebula no longer pops against the black velvet background of the distant Universe.

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Credits: NASA, ESA, B. Balick (University of Washington), M. Guerrero (Instituto de Astrofísica de Andalucía), and G. Ramos-Larios (Universidad de Guadalajara); CC BY 4.0

Planetary oddball Uranus rolls around the Sun on its side as it follows its 84-year orbit, rather than spinning in a more ’vertical’ position as Earth does. Its weirdly tilted ‘horizontal’ rotation axis is angled just eight degrees off the plane of the planet’s orbit. One recent theory proposes that Uranus once had a massive moon that gravitationally destabilised it and then crashed into it. Other possibilities include giant impacts during the formation of the planets, or even giant planets exerting resonant torques on each other over time. The consequences of Uranus’s tilt are that for stretches of time lasting up to 42 years, parts of one hemisphere are completely without sunlight. When the Voyager 2 spacecraft visited during the 1980s, the planet’s south pole was pointed almost directly at the Sun. Hubble’s latest view shows the northern pole now tipping toward the Sun.

[LEFT] - This is a Hubble view of Uranus taken in 2014, seven years after the northern spring equinox when the Sun was shining directly over the planet’s equator, and shows one of the first images from the OPAL programme. Multiple storms with methane ice-crystal clouds appear at mid-northern latitudes above the planet’s cyan-tinted lower atmosphere. Hubble photographed the ring system edge-on in 2007, but the rings are seen starting to open up seven years later in this view. At this time, the planet had multiple small storms and even some faint cloud bands.

[RIGHT] - As seen in 2022, Uranus’s north pole shows a thickened photochemical haze that looks similar to the smog over cities. Several little storms can be seen near the edge of the polar haze boundary. Hubble has been tracking the size and brightness of the north polar cap and it continues to get brighter year after year. Astronomers are disentangling multiple effects — from atmospheric circulation, particle properties, and chemical processes — that control how the atmospheric polar cap changes with the seasons. At the Uranian equinox in 2007, neither pole was particularly bright. As the northern summer solstice approaches in 2028 the cap may grow brighter still, and will be aimed directly toward Earth, allowing good views of the rings and the north pole; the ring system will then appear face-on. This image was taken on 10 November 2022.

[Image description: Two views of the tipped planet Uranus appear side-by-side for comparison.]

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Credits: NASA, ESA, STScI, A. Simon (NASA-GSFC), M. H. Wong (UC Berkeley), J. DePasquale (STScI); CC BY 4.0

Captured by the NASA/ESA Hubble Space Telescope, this image shows NGC 7513, a barred spiral galaxy. Located approximately 60 million light-years away, NGC 7513 lies within the Sculptor constellation in the southern hemisphere.

This galaxy is moving at the astounding speed of 1564 kilometres per second, and it is heading away from us. For context, the Earth orbits the Sun at about 30 kilometres per second. Though NGC 7513’s apparent movement away from the Milky Way might seem strange, it is not that unusual.

While some galaxies, like the Milky Way and the Andromeda galaxy, are caught in each other’s gravitational pull and will eventually merge together, the vast majority of galaxies in our Universe appear to be moving away from each other. This phenomenon is due to the expansion of the Universe, and it is the space between galaxies that is stretching, rather than the galaxies themselves moving.

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

This ghostly image shows what can happen when an interstellar cloud passes too close to a star. Barnard's Merope Nebula, also known as IC 349, is a cloud of interstellar gas and dust travelling through the Pleiades star cluster at a relative speed of 11 kilometres per second. It is passing close to the star Merope, located 0.06 light years away from the cloud, which is equivalent to about 3 500 times the distance between the Earth and the Sun. This passage is disrupting the nebula and creating the wispy effect seen in the image.

Merope is located just out of the frame at the top right. Light from the star is reflected from the surface of the cloud, which illuminates it to become what astronomers call a reflection nebula. The beams of light at the upper right from the star are an effect produced by the telescope but the eerie wisps of light from the lower left to upper right are real.

Astronomers believe that radiation pressure from the star is acting like a sieve to separate dust particles of different sizes. As the nebula approaches Merope, the starlight decelerates dust particles, but the small particles slow down more than the large particles. As an effect, the almost straight lines that are reaching out towards Merope in this view are made of large particles, whereas smaller-sized particles lag behind to create the wispy structure on the lower left.

The nebula will continue its approach towards Merope over the next few thousand years and will eventually move past the star, if it survives. Studying the nebula's interaction with the star is important as it provides a chance to observe interstellar material in an unusual situation and learn more about interstellar dust.

The nebula near Merope was discovered in 1890 by E.E. Barnard using the 36 inch telescope at the Lick Observatory in California. This image was captured by the NASA/ESA Hubble Space Telescope on 19 September 1999 and was originally published in 2000.

Credits: NASA/ESA and The Hubble Heritage Team (STScI/AURA), George Herbig and Theodore Simon (University of Hawaii); CC BY 4.0

While the Winter Olympics is in full swing in PyeongChang, South Korea, and many winter sport fanatics head to snow-clad mountains to get their thrills on the slopes this ski-season, this dramatic mountain scene is somewhat off-piste – in Saturn’s rings to be precise.

These fluffy peaks are among the tallest seen in Saturn’s main rings, towering as high as 2.5 km above the plane of the rings, a significant deviation from the vertical thickness of the planet’s main rings, which is generally only about 10 m. They rise abruptly from the edge of the B ring to cast long shadows in this image.

But these mountains are far from solid: they are constantly changing accumulations of ring particles that respond to the gravity of moonlets and wave-like formations induced in the rings.

Part of the Cassini Division, between the B and the A rings, appears at the top of the image, showing ringlets in the inner division. This is one prominent region at the outer edge of the B ring where moonlets up to a kilometre or more in size are found. It is possible that these bodies significantly affect the ring material streaming past them and force the particles upward in a ‘splashing’ manner, in reality making them impossible to ski.

Images like this are only possible around the time of Saturn’s equinox, which occurs every half-Saturn-year, or about every 15 Earth years. The illumination geometry that accompanies equinox lowers the Sun’s angle to the ring plane and causes structures jutting out of the plane to cast long shadows across the rings.

This image was taken by the international Cassini spacecraft’s narrow-angle camera on 26 July 2009, two weeks before the planet’s 11 August equinox, as the Sun shone directly edge-on to the ring plane.

This view looks toward the southern, sunlit side of the rings from about 32º below the ring plane. The view was acquired at a distance of 336 000 km from Saturn and at a Sun–Saturn–spacecraft, angle of 132º. Image scale is 2 km/ pixel and the image captures a 1200 km-long section arcing along the outer edge of the B ring.

The image was previously highlighted in a release on 1 November 2010.

The Cassini mission is a cooperative project of NASA, ESA and Italy’s ASI space agency. The mission concluded in September 2017.

Credits: NASA/JPL/SSI

This oblique perspective view shows the southern flanks of Ascraeus Mons, the second-tallest volcano on Mars.

A number of weaving depressions can be seen from this perspective; these are fissures and ‘coalesced pit crater troughs’, features where strings of circular or near-circular depressions have combined and coalesced to form troughs. They are part of a group of features – including lava flows and channel-like rilles – collectively named Ascraeus Chasmata, which encompasses an enormous patch of collapsed terrain over 70 km across.

This image was generated from the digital terrain model and the nadir and colour channels of the High Resolution Stereo Camera on ESA’s Mars Express.

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

This oblique perspective view of part of the scarred and colourful landscape that makes up Aonia Terra, an upland region in the southern highlands of Mars, was generated from the digital terrain model and the nadir and colour channels of the High Resolution Stereo Camera on ESA’s Mars Express.

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

The historic centre of Rome, Italy’s capital city, is featured in this image captured on 28 March 2023.

Known as the Eternal City, Rome lies on the banks of the Tiber River, the third longest river in Italy. The Tiber can be seen snaking its way through the city. The colour of the river water, owing to the sandy and silty riverbed, is why the Tiber is sometimes known as the ‘blond river’.

A number of world-famous sites are visible in this image.

The distinctive oval shape of the Colosseum, the largest Roman amphitheatre ever built, stands out near the centre right of the image, on the east side of the river and adjacent to the ruins of the Roman Forum and the Palatine Hill.

Below that is the elongated outline of the Circus Maximus, which was the largest chariot racetrack in ancient Rome. To the left on a bend in the river, is the boat-shaped Tiber Island, the only island in the urban part of the river.

Following the Tiber northwards, we find, to the east of the elliptical shape of Piazza Navona, the white open-topped dome of the Pantheon, which is over 43 metres in diameter.

A little further north on the other side of the river, we can see the sovereign state of Vatican City, with St. Peter’s Basilica and its famous square. The star-shaped Castel St. Angelo is also visible nearby. It was the tomb of Emperor Hadrian, but later served as a fortress.

As evident in the image, Rome has many green spaces: parks, historic villas and public gardens, together covering about 4000 hectares.

This image was acquired by the Pléiades Neo mission, a very high-resolution optical constellation. Pléiades Neo is part of ESA’s Third Party Missions programme, which means ESA uses its multi-mission ground systems and expertise to acquire, process, distribute and archive data from a wide range of satellite missions developed and operated by other agencies.

Credits: Airbus DS (2023)

The seven galaxies highlighted in this image from the NASA/ESA/CSA Telescope have been confirmed to be at a distance that astronomers refer to as redshift 7.9, which correlates to 650 million years after the big bang. This makes them the earliest galaxies yet to be spectroscopically confirmed as part of a developing cluster.

The seven galaxies confirmed by Webb were first established as candidates for observation using data from the NASA/ESA Hubble Space Telescope’s Frontier Fields program. The program dedicated Hubble time to observations using gravitational lensing, to observe very distant galaxies in detail. However, because Hubble cannot detect light beyond near-infrared, there is only so much detail it can see. Webb picked up the investigation, focusing on the galaxies scouted by Hubble and gathering detailed spectroscopic data in addition to imagery.

Astronomers used Webb's Near-Infrared Spectrograph (NIRSpec) instrument to precisely measure the distances and determine that the galaxies are part of a developing cluster. Galaxy YD4, previously estimated to be at a further distance based on imaging data alone, was able to be more accurately placed at the same redshift as the other galaxies. Before Webb, astronomers did not have high resolution imaging or spectral infrared data available to do this type of science.

At extreme distances, astronomers use the redshift reference to account for the fact that, as the universe expands, wavelengths of light are stretched and “shifted” to redder wavelengths, which are longer. Shorter wavelengths, for example ultraviolet and X-ray, are toward the bluer end of the electromagnetic spectrum. So extreme distances in the early universe are referenced by how much the light emitted there has been shifted as it travelled through space to be detected by a telescope.

The results have been published in the Astrophysical Journal Letters.

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Webb is the largest, most powerful telescope ever launched into space. Under an international collaboration agreement, ESA provided the telescope’s launch service, using the Ariane 5 launch vehicle. Working with partners, ESA was responsible for the development and qualification of Ariane 5 adaptations for the Webb mission and for the procurement of the launch service by Arianespace. ESA also provided the workhorse spectrograph NIRSpec and 50% of the mid-infrared instrument MIRI, which was 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 is an international partnership between NASA, ESA and the Canadian Space Agency (CSA).

Credits: NASA, ESA, CSA, T. Morishita (IPAC), A. Pagan (STScI)

Sometimes it’s all about perspective. This very convincing image of a conjoined moon masquerading as a snowman is actually two separate Saturnian moons – Dione and Rhea – taken from such an angle by the international Cassini spacecraft that they appear as one.

Dione (top) was actually closer to the spacecraft at the time the image was taken, at around 1.1 million kilometres, compared to Rhea (bottom) which was around 1.6 million kilometres from Cassini. Dione has a diameter of 1123 kilometres and Rhea is larger with a diameter of 1528 kilometres, but they appear to have a similar size in this image due to the difference in distance.

The moons also orbit Saturn at different distances: Dione lies at roughly the same distance as the Moon from the Earth and orbits around the ringed planet in just 2.7 days, while Rhea sits slightly further away and has a 4.5 day orbit.

Dione has a large crater called Evander, centred at the south polar region, which allows the two moons to blend seamlessly together in this view. They also have a similar reflectivity, contributing to the snowman-like appearance, while also pointing to a comparable surface composition.

Dione is made of around one third rock, comprising the core, and two thirds ice with a suspected subsurface ocean.

Interestingly, the moon is more heavily cratered on the hemisphere that faces away from the direction of motion compared to the hemisphere that faces the direction of motion, opposite to what is expected as the forward facing side of the moon should be bombarded with more material. This unusual cratering pattern suggests that it suffered an impact which spun the moon around 180 degrees.

Rhea is Saturn’s second largest moon, after Titan, and is similar to Dione in density, but is around one quarter rock mixed with three quarters ice – a giant frozen dirty snowball.

The image was taken on 27 July 2010 by Cassini in visible light using the narrow-angle camera. The resolution is seven kilometres per pixel on Dione and ten kilometres per pixel on Rhea. Saturn is towards the right and out of view. The Cassini mission is a cooperative project of NASA, ESA and Italy’s ASI space agency. The mission concluded in September 2017.

Credits: NASA/JPL/Space Science Institute

In celebration of the 31st anniversary of the launching of the NASA/ESA Hubble Space Telescope, astronomers aimed the celebrated observatory at one of the brightest stars seen in our galaxy to capture its beauty.

The giant star featured in this latest Hubble Space Telescope anniversary image is waging a tug-of-war between gravity and radiation to avoid self-destruction. The star, called AG Carinae, is surrounded by an expanding shell of gas and dust — a nebula. The nebula is about five light-years wide, which equals the distance from here to our nearest star, Alpha Centauri.

The huge structure was created from one or more giant eruptions several thousand years ago. The star’s outer layers were blown into space, the expelled material amounting to roughly 10 times the mass of our Sun. These outbursts are typical in the life of a rare breed of star called a Luminous Blue Variable (LBV), a brief unstable phase in the short life of an ultra-bright, glamorous star that lives fast and dies young. These stars are among the most massive and brightest stars known. They live for only a few million years, compared to the roughly 10-billion-year lifetime of our own Sun. AG Carinae is a few million years old and resides 20 000 light-years away inside our Milky Way galaxy. The star’s expected lifetime is between 5 million and 6 million years.

LBVs have a dual personality. They appear to spend years in semi-quiescent bliss and then they erupt in a petulant outburst, during which their luminosity increases — sometimes by several orders of magnitude. These behemoths are stars in the extreme, far different from normal stars like our Sun. In fact AG Carinae is estimated to be up to 70 times more massive than our Sun and shines with the blinding brilliance of 1 million suns.

Major outbursts such as the one that produced the nebula featured in this image occur a few times during a LBV’s lifetime. A LBV star only casts off material when it is in danger of self-destruction. Because of their massive forms and super-hot temperatures, luminous blue variable stars like AG Carinae are in a constant battle to maintain stability. It’s an arm-wrestling contest between radiation pressure from within the star pushing outward and gravity pressing inward. This arm-wrestling match results in the star’s expanding and contracting. The outward pressure occasionally wins the battle, and the star expands to such an immense size that it blows off its outer layers, like a volcano erupting. But this outburst only happens when the star is on the verge of coming apart. After the star ejects the material, it contracts to its normal (large) size, settles back down, and becomes stable again.

LBV stars are rare: fewer than 50 are known among the galaxies in our local group of neighbouring galaxies. These stars spend tens of thousands of years in this phase, a blink of an eye in cosmic time. Some are expected to end their lives in titanic supernova blasts, which enrich the Universe with the heavier elements beyond iron.

Like many other LBVs, AG Carinae remains unstable. It has experienced lesser outbursts that have not been as powerful as the one that created the present nebula. Although AG Carinae is semi-quiescient now, its searing radiation and powerful stellar wind (streams of charged particles) have been shaping the ancient nebula, sculpting intricate structures as outflowing gas slams into the slower-moving outer nebula. The wind is travelling at up to 1 million kilometres per hour, about 10 times faster than the expanding nebula. Over time, the hot wind catches up with the cooler expelled material, ploughs into it, and pushes it farther away from the star. This “snowplough” effect has cleared a cavity around the star.

The red material is glowing hydrogen gas laced with nitrogen gas. The diffuse red material at upper left pinpoints where the wind has broken through a tenuous region of material and swept it into space. The most prominent features, highlighted in blue, are filamentary structures shaped like tadpoles and lopsided bubbles. These structures are dust clumps illuminated by the star’s light. The tadpole-shaped features, most prominent at left and bottom, are denser dust clumps that have been sculpted by the stellar wind. Hubble’s sharp vision reveals these delicate-looking structures in great detail.

The image was taken in visible and ultraviolet light. Hubble is ideally suited for observations in ultraviolet light because this wavelength range can only be viewed from space.

Credits: NASA, ESA and STScI; CC BY 4.0

On 5 April 2018, Ariane 5 flight VA242 lifted off from Europe’s Spaceport in French Guiana and delivered two telecom satellites, DSN-1/Superbird-8 and Hylas-4, into their planned orbits.

Credits:: 2018 ESA-CNES-Arianespace / Optique vidéo du CSG - S. Martin

While much of Europe is on drought alert, this image, captured from space by Copernicus Sentinel-1 on 30 August 2022, shows the extent of flooding that is currently devastating Pakistan. Heavy monsoon rainfall – ten times heavier than usual – since mid-June have led to more than a third of the country now being underwater.

This catastrophic flood has claimed the lives of more than 1100 people and more than 33 million, one in seven Pakistanis, have been affected by the flooding. Homes, croplands and infrastructure have been washed away. Prime Minister of Pakistan, Shehbaz Sharif, describes the flood as the worst in the country’s history and says it will cost at least $10 billion to repair damaged infrastructure.

The left side of the Copernicus Sentinel-1 image shows a wide view of the area affected and the image on the right zooms into the area between Dera Murad Jamali and Larkana. The Indus River has overflowed, effectively creating a long lake, tens of kilometres wide. The blue to black colours show where the land is submerged.

The Copernicus Emergency Management Service has been activated to provide flood maps from space to help responders deal with the crisis.

Europe’s Copernicus Sentinel-1 mission carries a radar instrument to ‘see’ through clouds and rain darkness, making it particularly useful for monitoring floods.

Credits: contains modified Copernicus Sentinel data (2022), processed by ESA, CC BY-SA 3.0 IGO

While heatwaves are quite common during the summer months, the scorching heatwave hitting parts of western Canada and the US has been particularly devastating – with temperature records shattered and hundreds of people falling victim to the extreme heat.

Canada broke its temperature record for a third consecutive day: recording a whopping 49.6°C on 29 June in Lytton, a village northeast of Vancouver, in British Columbia.

Portland, Oregon, also broke its all-time temperature record for three days in a row.

The extent of the heatwave can be seen in this map, which shows the land surface temperature of parts of Canada and the US on 29 June. The data show that surface temperatures in Vancouver reached 43°C, and Calgary and Portland recorded 43°C. The hottest temperatures recorded are in the state of Washington (visible in deep red) with maximum land surface temperatures of around 69°C.

The map has been generated using data from the Copernicus Sentinel-3 mission. While weather forecasts typically use air temperatures, the Sea and Land Surface Temperature Radiometer onboard Sentinel-3 measures the energy radiating from Earth’s surface. Therefore, the map shows the actual temperature of the land’s surface pictured here, which can be significantly hotter or colder than air temperatures.

The light blue in the image represents either snow and ice or cloud coverage. Snow and ice can be seen, for example, in the mountain ranges of Canada and Mount Rainier in the US, while some clouds can be seen on the Pacific Coast and in the bottom right of the map.

The persistent heat over parts of western Canada and parts of the US has been caused by a heat dome stretching from California to the Arctic. Temperatures have been easing in coastal areas, but there has been little respite for the inland regions.

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

A composite view of the Abell 2384 system, comprising two galaxy clusters located 1.2 billion light years from Earth.

The X-ray view from ESA's XMM-Newton and NASA's Chandra X-ray observatories is shown in blue, alongside observations in radio waves performed with the Giant Metrewave Radio Telescope in India (shown in red) and optical data from the Digitized Sky Survey (shown in yellow).

The two clusters, comprising each many galaxies, vast amounts of hot gas even larger amounts of unseen dark matter, are linked by a three million light-year long bridge of hot gas that shines brightly in X-rays.

This new multi-wavelength view reveals the effects of a jet shooting away from a supermassive black hole in the center of a galaxy in one of the clusters.

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Credits: X-ray: NASA/CXC/SAO/V.Parekh, et al. & ESA/XMM-Newton; Radio: NCRA/GMRT

This oblique perspective view of Nectaris Fossae and Protva Valles on Mars was generated from the digital terrain model and the nadir and colour channels of the High Resolution Stereo Camera on ESA’s Mars Express. A large impact crater features in the bottom left, stretching partially out of frame, with four smaller craters dotted across to its right. Some textures and grooves can be seen in the more distant surface.

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

Part of the Frisian Islands, a low-lying archipelago just off the coast of northern Europe, is visible in this image captured by the Copernicus Sentinel-2 mission.

The Frisian Islands stretch from the northwest of the Netherlands through Germany to the west of Denmark. Although they are considered a single physical feature, they are divided into West, East and North Frisian Islands – with the North Frisian Islands visible here.

The North Frisian Islands are split between Germany and Denmark. There are four larger islands that make up the archipelago: Sylt, Föhr, Amrum, and Pellworm.

Sylt, the largest of the archipelago, is around 100 sq km and is known for its distinctive shape of its shoreline. Sylt extends in length more than 35 km and, in some places, is only 1 km wide. A sandy beach stretches across the islands’ west coast, however it has begun to erode owing to storm tides. The northernmost island of Germany, it is connected to the mainland by the Hindenburgdamm, an 11 km-long causeway.

The Wadden Sea on the islands’ east side, between Sylt and the mainland, is part of the Schleswig-Holstein Wadden Sea National Park and has been a nature reserve and bird sanctuary since 1935.

The islands of Föhr and Amrum are visible southeast of Sylt. The larger Föhr is called the ‘Green Island’ due to it being sheltered from the storms of the North Sea by its neighbouring islands. The island of Amrum features an extended beach area along its west coast, which faces the open North Sea. The east coast borders to mud flats and tidal creeks of the Wadden Sea.

The three white islands visible below Amrum are the North Frisian Barrier Islands. These sand banks, or shoals, act as a natural breakwater for the smaller islands closer to land. Just east of these lies the island of Pellworm.

North of Sylt lie the Danish islands of Rømø, Mandø, and, lastly, Fanø. In the top-left of the image, a large algal bloom is visible in emerald green. Harmful algal blooms caused by excessive growth of marine algae have occurred in the North Sea in recent years, with satellite data being used to track their growth and spread. These data can then be used to help develop alert systems to mitigate against damaging impacts for tourism and fishing industries.

This image, captured on 1 June 2020, 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

Someone decked the skies with boughs of sprites.

The red jellyfish in the sky is a unique red sprite high above a storm across the southern plains of the United States.

Taken in the early hours of 21 October by outdoor photographer Paul Smith, red sprites, along with blue jets and elves, are elusive electrical discharges in the upper atmosphere that are difficult to study as they occur over thunderstorms and propagate out into space.

“There were some very strong events and many dancing sprites as the storms matured,” says Paul.

“I was so amazed to capture some very bright reflections in the lake I was shooting from. I was out until the early hours of the morning and got home at 5:00, but so worth it!” The photo was taken from Lake Acadia, Oklahoma. Watch a video of the storm here.

Sightings of these elusive high altitude optical phenomena had long been based on hearsay and appeared to be linked with thunderstorms. First camera images of red sprites were obtained about 30 years ago. The scientific community was intrigued and wanted to learn more, leading to the creation of an observatory that is now aboard the International Space Station.

Called the Atmosphere-Space Interactions Monitor, or ASIM, the suite of instruments includes optical cameras and photometers to capture red sprites and other high altitude luminous events as well as lightning. ASIM also carries a Gamma-ray detector to study so-called Terrestrial Gamma-ray Flashes (TGFs).

All these instruments are mounted together outside the European Columbus module and look downwards towards the Earth. The combination of optical and Gamma-ray detectors in the same payload makes it possible to describe the lightning processes that lead to TGF emissions. ASIM provides the highest ever spatial and temporal resolution for the study of electrical activity linked to thunderstorms.

New data from ASIM will improve our understanding of the effect of thunderstorms on the atmosphere and thus contribute to more accurate climate models.

The data ASIM is generating has been made available to the public for the first time and can be consulted at the ASIM Science Data Center. A recent paper was also published in Science magazine.

Though they are difficult to detect due to their faintness and the fact that they disappear within milliseconds, the conditions from Earth were just right to catch these sprites in action.

You can find more of Paul’s work on his website, Facebook, Twitter, and YouTube.

Credits: Paul M. Smith

Observations by the NASA/ESA Hubble Space Telescope recently revealed water vapour in the atmosphere of Ganymede, one of Jupiter’s moons. A new analysis of archival images and spectra has now revealed that water vapour is also present in the atmosphere of Jupiter’s icy moon Europa. The analysis found that a water vapour atmosphere is present only on one hemisphere of the moon. This result advances our understanding of the atmospheric structure of icy moons, and helps lay the groundwork for upcoming science missions which will explore Jupiter’s icy moons.

Europa — one of Jupiter’s 79 moons — is both the sixth closest moon to Jupiter and the sixth largest moon in the Solar System. It is an icy orb larger than the dwarf planet Pluto with a smooth, icy surface scarred by cracks and fissures. The surface of the moon is a bleak environment with an average temperature of −171 °C and only a tenuous atmosphere. However, astronomers suspect that Europa harbours a vast ocean underneath its icy surface, which some scientists speculate could host extraterrestrial life. Now, for the first time, an astronomer has discovered evidence for persistent water vapour in the atmosphere of Europa.

Using a technique that recently resulted in the discovery of water vapour in the atmosphere of Jupiter’s moon Ganymede, an astronomer has found evidence of water in Europa’s trailing hemisphere — the portion of the moon that is always opposite to its direction of motion. The asymmetric distribution of water vapour was predicted by previous studies based on computer simulations, but had not previously been detected observationally.

“The observation of water vapour on Ganymede and on the trailing side of Europa advances our understanding of the atmospheres of icy moons,” commented Lorenz Roth of the KTH Royal Institute of Technology in Stockholm, Sweden, the author of this study. “The detection of a stable H2O abundance on Europa is surprising because the surface temperatures are so low.”

To make this discovery, Roth delved into archival Hubble datasets, selecting ultraviolet observations of Europa from 1999, 2012, 2014 and 2015 while the moon was at various orbital positions. These observations were all taken with one of Hubble’s most versatile instruments — the Space Telescope Imaging Spectrograph (STIS). These ultraviolet STIS observations allowed Roth to determine the abundance of oxygen — one of the constituents of water — in Europa’s atmosphere, and by interpreting the strength of emission at different wavelengths he was able to infer the presence of water vapour.

Previous observations of water vapour on Europa have been associated with transient plumes erupting through the ice, analogous to geysers here on Earth but more than 100 kilometres high. The phenomena seen in these plume studies were apparently transient inhomogeneities or blobs in the atmosphere. The new results, however, show similar amounts of water vapour to be present spread over a larger area in observations spanning from 1999 to 2015. This suggests the long-term presence of a water vapour atmosphere on Europa’s trailing hemisphere. Despite the presence of water vapour on Europa’s trailing hemisphere there is no indication of H2O on the leading hemisphere of Europa.

Space scientists working to understand these icy moons will soon be able to benefit from a close-up view. ESA’s JUpiter ICy moons Explorer (JUICE) mission is being prepared for a tour of Ganymede, Callisto and Europa, Jupiter’s three largest icy moons. JUICE is the first large-class mission in ESA's Cosmic Vision 2015–2025 programme and is expected to launch in 2022 and arrive at Jupiter in 2031. The probe will carry an advanced suite of instruments — the most powerful remote sensing payload ever flown to the outer Solar System — and will spend at least three years making detailed observations of the Jovian system. Europa will also be visited by a NASA mission, Europa Clipper, which will perform a series of flybys of the moon and investigate its habitability, as well as selecting a landing site for a future mission.

“This result lays the groundwork for future science based on upcoming missions to the Jovian moons,” concluded Roth. “The more we can understand about these icy moons before spacecraft like JUICE and Europa Clipper arrive, the better use we can make of our limited observing time within the Jovian system.”

This discovery and the insights from upcoming missions such as JUICE will improve our understanding of potentially habitable environments in the Solar System. Understanding the formation and evolution of Jupiter and its moons also helps astronomers gain insights into Jupiter-like exoplanets around other stars. Combined with observations from space telescopes such as the upcoming NASA/ESA/CSA James Webb Space Telescope, this could help astronomers determine if life could emerge in Jupiter-like exoplanetary systems elsewhere in the universe.

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

New observations made with ESA’s X-ray XMM Newton telescope have revealed an “orphan cloud” – an isolated cloud in a galaxy cluster that is the first discovery of its kind.

A lot goes on in a galaxy cluster. There can be anything from tens to thousands of galaxies bound together by gravity. The galaxies themselves have a range of different properties, but typically contain systems with stars and planets, along with the material in between the stars – the interstellar medium. In between the galaxies is more material – tenuous hot gas known as the intercluster medium. And sometimes in all the chaos, some of the interstellar medium can get ripped out of a galaxy and get stranded in an isolated region of the cluster, as this new study reveals.

Unexpected discovery

Abell 1367, also known as the Leo Cluster, is a young cluster that contains around 70 galaxies and is located around 300 million light-years from Earth. In 2017, a small warm gas cloud of unknown origin was discovered in A1367 by the Subaru telescope in Japan. A follow-up X-ray survey to study other aspects of A1367 unexpectedly discovered X-rays emanating from this cloud, revealing that the cloud is actually bigger than the Milky Way.

This is the first time an intercluster clump has been observed in both X-rays and the light that comes from the warm gas. Since the orphan cloud is isolated and not associated with any galaxy, it has likely been floating in the space between galaxies for a long time, making its mere survival surprising.

The discovery of this orphan cloud was made by Chong Ge at the University of Alabama in Huntsville, and colleagues, and the study has been published in Monthly Notices of the Royal Astronomical Society.

Along with data from XMM-Newton and Subaru, Chong and colleagues also used the Multi Unit Spectroscopic Explorer (MUSE) on the Very Large Telescope (VLT) to observe the cluster in visible light.

The orphan cloud is the blue umbrella-shaped part of the image. It has been colour-coded to show the X-ray part of the cloud in blue, the warm gas in red, and the visible region in white shows some of the galaxies in the cluster. The part of the cloud that had been discovered in 2017 (in red) overlaps with the X-ray at the bottom of the cloud.

How the cloud became an orphan

It was previously thought that the distribution of material between galaxies is smooth, however more recent X-ray studies have revealed the presence of clumps in clusters. It was theorised that clumps of gas in the clusters were originally the gas that exists between stars in individual galaxies. The intercluster gas acts as a wind that is strong enough to pull the interstellar gas out of the galaxy as the galaxy is moving through the cluster. However, observations showing that intercluster clumps are originally stripped interstellar material have never been made until now. The observation of the warm gas in the clump provides the evidence to show that this orphan cloud originated within a galaxy. Interstellar material is much cooler than intercluster material, and the temperature of the orphan cloud matches that of interstellar gas. The researchers were also able to determine why the orphan cloud has survived for as long as it has. An isolated cloud would be expected to be ripped apart by instabilities caused by velocity and density differences. However, they found that a magnetic field in the cloud would be able to suppress these instabilities.

Searching for the parent galaxy

It is likely that the parent galaxy of the orphan cloud is a massive one as the mass of the X-ray gas in the orphan is substantial. It is possible that the parent might one day be discovered with future observations by following some breadcrumbs. For example, there are traces of the warm gas that extend beyond the orphan cloud that could be used to identify the parent with more data. There are other unsolved mysteries regarding the cloud that could be deciphered with more observations, such as mysterious offset between the brightest X-rays and the brightest light from the warm gas.

A closer inspection of this orphan will also further our understanding of the evolution of stripped interstellar medium at such a great distance from its parent galaxy and will provide a rare laboratory to study other things such as turbulence and heat conduction. This study paves the way for research on intercluster clumps, as future warm gas surveys can now be targeted to search for other orphan clouds.

Credits: Ge et al (2021)

The NASA/ESA Hubble Space Telescope has made its stunning yearly observations of the Solar System’s giant planets, to reveal atmospheric changes.

The NASA/ESA Hubble Space Telescope has completed its annual grand tour of the outer Solar System. This is the realm of the giant planets — Jupiter, Saturn, Uranus, and Neptune — extending as far as 30 times the distance between Earth and the Sun. Unlike the rocky terrestrial planets like Earth and Mars that huddle close to the Sun’s warmth, these far-flung worlds are mostly composed of chilly gaseous soups of hydrogen, helium, ammonia, and methane around a packed, intensely hot, compact core.

Though robotic spacecraft have sent back snapshots of their visits to these four monster planets over the past 50 years, their swirling, colourful atmospheres are constantly changing. Fulfilling the role of a weather forecaster, every time Hubble’s sharp cameras revisit these worlds there are new surprises, offering fresh insights into their wild weather, driven by still largely unknown dynamics taking place under the cloudtops.

Hubble’s snapshots of the outer planets reveal both extreme and subtle changes rapidly taking place in these distant worlds. Hubble’s sharp view gleans insights into the fascinating, dynamic weather patterns and seasons on these gas giants and allows astronomers to investigate the very similar — and very different — variables that contribute to their changing atmospheres.

Jupiter

This year’s Hubble observations of Jupiter track the ever-changing landscape of its turbulent atmosphere, where several new storms are making their mark and the planet’s equator has changed colour yet again.

Hubble’s 4 September photo puts the giant planet’s tumultuous atmosphere on full display. The planet’s equatorial zone is now a deep orange hue, which researchers are calling unusual. While the equator has departed from its traditional white or beige appearance for a few years now, scientists were surprised to find a deeper orange in Hubble’s recent imaging, when they were expecting the zone to cloud up again.

Just above the equator, researchers note the appearance of several new storms, nicknamed “barges.” These elongated, deeply structured red cells can be defined as cyclonic vortices, which vary in appearance. Whilst some of the storms are sharply defined and clear, others are fuzzy and hazy. This difference in appearance is caused by the physical properties within the clouds of the vortices.

Researchers also note that a feature dubbed “Red Spot Jr.” (Oval BA), below the Great Red Spot where Hubble just discovered winds are speeding up, is still a darker beige colour, and is joined by several additional white, cyclonic storms to the south.

Hubble’s crisp views of Jupiter in 2020 was one of the most popular ESA/Hubble photo releases to date.

Saturn

Hubble’s new look at Saturn on 7 September 2021 shows rapid and extreme colour changes in the bands in the planet’s northern hemisphere, where it is now early autumn. The bands have varied throughout Hubble observations in both 2019 and 2020. Hubble’s Saturn image catches the planet following the southern hemisphere’s winter, evident in the lingering blue-ish hue of the south pole.

Uranus

Hubble’s 25 October view of Uranus puts the planet’s bright northern polar hood in the spotlight. It’s springtime in the northern hemisphere and the increase in ultraviolet radiation from the Sun seems to be causing the polar region to brighten. Researchers aren’t sure why. It could be a change in the opacity of atmospheric methane haze, or some variation in the aerosol particles. Curiously, even as the atmospheric hood gets brighter, the sharp southernmost boundary remains at the same latitude. This has been constant over the past several years of Hubble observations of the planet. Perhaps some sort of jetstream is setting up a barrier at that latitude of 43 degrees.

Neptune

In observations taken on 7 September 2021, researchers found that Neptune’s dark spot, which was recently found to have reversed course from moving towards the equator, is still visible in this image, along with a darkened northern hemisphere. There is also a notable dark, elongated circle encompassing Neptune’s south pole. The blue colour of both Neptune and Uranus is a result of the absorption of red light by the planets’ methane-rich atmospheres.

Notes

These new Hubble images form part of yearly maps of the entire planet taken under the Outer Planets Atmospheres Legacy programme, or OPAL. The programme provides yearly Hubble global views of the outer planets to look for changes in their storms, winds, and clouds.

Note: The planets are not shown to scale in this image.

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

This remarkable spiral galaxy, known as NGC 4651, may look serene and peaceful as it swirls in the vast, silent emptiness of space, but don’t be fooled — it keeps a violent secret. It is believed that this galaxy consumed another smaller galaxy to become the large and beautiful spiral that we observe today.

Although only a telescope like the NASA/ESA Hubble Space Telescope, which captured this image, could give us a picture this clear, NGC 4651 can also be observed with an amateur telescope — so if you have a telescope at home and a star-gazing eye, look out for this glittering carnivorous spiral.

Credits: ESA/Hubble & NASA, D. Leonard; CC BY 4.0

Three views of the same supernova appear in the 2016 image on the left, taken by the NASA/ESA Hubble Space Telescope. But they're gone in the 2019 image. The distant supernova, named Requiem, is embedded in the giant galaxy cluster MACS J0138. The cluster is so massive that its powerful gravity bends and magnifies the light from the supernova, located in a galaxy far behind it. Called gravitational lensing, this phenomenon also splits the supernova's light into multiple mirror images, highlighted by the white circles in the 2016 image.

The multiply imaged supernova disappears in the 2019 image of the same cluster, at right. The snapshot, taken in 2019, helped astronomers confirm the object's pedigree. Supernovae explode and fade away over time. Researchers predict that a rerun of the same supernova will make an appearance in 2037. The predicted location of that fourth image is highlighted by the yellow circle at top left.

The light from Supernova Requiem needed an estimated 10 billion years for its journey, based on the distance of its host galaxy. The light that Hubble captured from the cluster, MACS J0138.0-2155, took about 4 billion years to reach Earth.

The images were taken in near-infrared light by Hubble's Wide Field Camera 3.

Credits: NASA, ESA, Steve A. Rodney (University of South Carolina), Gabriel Brammer (Cosmic Dawn Center/Niels Bohr Institute/University of Copenhagen), Joseph DePasquale (STScI); CC BY 4.0

Cassini ended its 13-year mission at Saturn on 15 September 2017 when it plunged into the gas giant's atmosphere, but the NASA/ESA Hubble Space Telescope is still keeping an eye on the ringed planet.

This is a composite image taken by Hubble on 6 June 2018 showing a fully-illuminated Saturn and its rings, along with six of its 62 known moons. The visible moons are (from left to right) Dione, Enceladus, Tethys, Janus, Epimetheus and Mimas (click here for an annotated version). Dione is the largest moon in the picture, with a diameter of 1123 km, compared to the smallest, oddly-shaped Epimetheus with a diameter around 116 km.

During Cassini’s mission, Enceladus was identified as one of the most intriguing moons, with the discovery of water vapour jets spewing from the surface implying the existence of a subsurface ocean. Icy moons with subsurface oceans could potentially offer the conditions to harbour life, and understanding their origins and properties are essential for furthering our knowledge of the Solar System. ESA's JUpiter ICy moons Explorer (Juice), due to launch in 2022, aims to continue this theme by studying Jupiter's ocean-bearing moons: Ganymede, Europa, and Callisto.

The Hubble image shown here was taken shortly before Saturn's opposition on 27 June, when the Sun, Earth and Saturn were aligned so that the Sun fully illuminated Saturn as seen from Earth. Saturn's closest approach to Earth occurs around the same time as opposition, which makes it appear brighter and larger and allows the planet to be imaged in greater detail.

In this image the planet’s rings are seen near their maximum tilt towards Earth. Towards the end of Cassini’s mission, the spacecraft made multiple dives through the gap between Saturn and its rings, gathering spectacular data in this previously unchartered territory.

The image also shows a hexagonal atmospheric feature around the north pole, with the remnants of a storm, seen as a string of bright clouds. The hexagon-shaped cloud phenomenon is a stable and persistent feature first seen by the Voyager 1 space probe when it flew past Saturn 1981. In a study published just last week, scientists using Cassini data collected between 2013 and 2017, as the planet approached northern summer, identified a hexagonal vortex above the cloud structure, showing there is still much to learn about the dynamics of Saturn’s atmosphere.

The Hubble observations making up this image were performed as part of the Outer Planet Atmospheres Legacy (OPAL) project, which uses Hubble to observe the outer planets to understand the dynamics and evolution of their complex atmospheres. This was the first time that Saturn was imaged as part of OPAL. This image was first published on 26 July.

Credits: NASA, ESA, A. Simon (GSFC) and the OPAL Team, and J. DePasquale (STScI); CC BY 4.0

This image from the NASA/ESA Hubble Space Telescope shows a pair of quasars (known as J0749+2255) that existed when the Universe was just 3 billion years old. They are embedded inside a pair of colliding galaxies. The quasars are separated by less than the size of a single galaxy. Quasars are powered by voracious, supermassive black holes blasting out ferocious fountains of energy as they engorge themselves on gas, dust, and anything else within their gravitational grasp. The black holes will eventually merge.

This discovery required the combined power of the NASA/ESA Hubble Space Telescope and the W.M. Keck Observatories in Hawaii. Multi-wavelength observations from the International Gemini Observatory in Hawaii, NSF's Karl G. Jansky Very Large Array in New Mexico, and NASA's Chandra X-ray Observatory also contributed to understanding the dynamic duo. And, ESA's Gaia space observatory helped identify this double quasar in the first place.

Hubble shows, unequivocally, that this is indeed a genuine pair of supermassive black holes, rather than two images of the same quasar created by a foreground gravitational lens. And, Hubble shows a tidal feature from the merging of two galaxies, where gravity distorts the shape of the galaxies forming two tails of stars.

However, Hubble's sharp resolution alone isn't good enough to go looking for these dual light beacons. Researchers enlisted Gaia, which launched in 2013, to pinpoint potential double-quasar candidates. Gaia measures the positions, distances, and motions of nearby celestial objects very precisely. But in a novel technique, it can be used to explore the distant universe. Gaia's huge database can be used to search for quasars that mimic the apparent motion of nearby stars. The quasars appear as single objects in the Gaia data because they are so close together. However, Gaia can pick up a subtle, unexpected "jiggle" that mimics an apparent change in position of some of the quasars it observes. In reality, the quasars aren't moving through space in any measurable way. Instead, their jiggle could be evidence of random fluctuations of light as each member of the quasar pair varies in brightness on timescales of days to months, depending on their black hole's feeding schedule. This alternating brightness between the quasar pair is similar to seeing a railroad crossing signal from a distance. As the lights on both sides of the stationary signal alternately flash, the sign gives the illusion of "jiggling."

Because Hubble peers into the distant past, this double quasar no longer exists. Over the intervening 10 billion years, their host galaxies have likely settled into a giant elliptical galaxy, like the ones seen in the local universe today. And, the quasars have merged to become a gargantuan, supermassive black hole at its centre. The nearby giant elliptical galaxy, M87, has a monstrous black hole weighing 6.5 billion times the mass of our Sun. Perhaps this black hole was grown from one or more galaxy mergers over the past billions of years.

[Image description: A close-up image of a dual quasar system is shown. They appear as two large, white blurry circles in the centre of the image.]

Credits: NASA, ESA, Yu-Ching Chen (UIUC), Hsiang-Chih Hwang (IAS), Nadia Zakamska (JHU), Yue Shen (UIUC)

The Copernicus Sentinel-2 mission takes us over northwest Lesotho – a small, land-locked country surrounded entirely by South Africa.

Known for its tall mountains and narrow valleys, Lesotho is the only nation in the world that lies completely above 1000 m in elevation. Lesotho has an area of just 30 000 sq km, around the same size as Belgium, and has a population of around two million.

Around 80% of the country’s population lives in rural areas and more than three quarters of these people are engaged in agriculture – mostly traditional, rainfed cereal production and extensive animal grazing. The country’s agricultural system faces a growing number of issues, including a small portion of the land deemed arable, as well as other climate-related vulnerabilities such as drought, floods and extreme temperatures occurring more frequently.

This composite image was created by combining three separate images from the near-infrared channel from the Copernicus Sentinel-2 mission over a period of nine months.

The first image, captured on 27 November 2020, is assigned to the red channel and represents the onset of the wet summer season; the second from 12 March 2021, represents green, and was captured towards the end of the wet season; and the third from 19 August 2021 covers the blue part of the spectrum, captured during the short, dry season.

All other colours visible in the image are different mixtures of red, green and blue, and vary according to the stage of vegetation growth. A distinct pattern emerges due to topographical differences in this mountainous landscape, such as altitude and slope, which influence local water availability.

Maseru, the capital and largest urban centre of Lesotho, lies directly on the Lesotho— South Africa border. The city is located on the left bank of the Caledon River, also known as the Mohokare River, visible in black.

The Copernicus Sentinel-2 mission is designed to provide images that can be used to distinguish between different crop types as well as data on numerous plant indices, such as leaf area, leaf chlorophyll and leaf water. The mission’s revisit time of just five days, along with the mission’s range of spectral bands, mean that changes in plant health and growth can be more easily monitored.

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

Credits: contains modified Copernicus Sentinel data (2020-21), processed by ESA, CC BY-SA 3.0 IGO