This jewel-bright image from the NASA/ESA Hubble Space Telescope shows NGC 1385, a spiral galaxy 68 million light-years away from Earth, which lies in the constellation Fornax. The image was taken with Hubble’s Wide Field Camera 3 (WFC3), which is often referred to as Hubble’s workhorse camera, thanks to its reliability and versatility. It was installed in 2009 when astronauts last visited Hubble, and 12 years later it remains remarkably productive.

NGC 1385’s home — the Fornax constellation — is not named after an animal or an ancient God, as are many of the other constellations. Fornax is simply the Latin word for a furnace. The constellation was named Fornax by Nicolas-Louis de Lacaille, a French astronomer who was born in 1713. Lacaiile named 14 of the 88 constellations that are still recognised today. He seems to have had a penchant for naming constellations after scientific instruments, including Atlia (the air pump), Norma (the ruler, or set square) and Telescopium (the telescope).

Credits: ESA/Hubble & NASA, J. Lee and the PHANGS-HST Team; CC BY 4.0

This cosmic portrait — captured with the NASA/ESA Hubble Space Telescope’s Wide Field Camera 3 — shows a stunning view of the spiral galaxy NGC 4571, which lies approximately 60 million light-years from Earth in the constellation Coma Berenices. This constellation — whose name translates as Bernice’s Hair — was named after an Egyptian queen who lived more than 2200 years ago.

As majestic as spiral galaxies like NGC 4571 are, they are far from the largest structures known to astronomers. NGC 4571 is part of the Virgo cluster, which contains more than a thousand galaxies. This cluster is in turn part of the larger Virgo supercluster, which also encompasses the Local Group which contains our own galaxy, the Milky Way. Even larger than superclusters are galaxy filaments — the largest known structures in the Universe.

This image comes from a large programme of observations designed to produce a treasure trove of combined observations from two great observatories: Hubble and ALMA. ALMA, The Atacama Large Millimeter/submillimeter Array, is a vast telescope consisting of 66 high-precision antennas high in the Chilean Andes, which together observe at wavelengths between infrared and radio waves. This allows ALMA to detect the clouds of cool interstellar dust which give rise to new stars. Hubble’s razor-sharp observations at ultraviolet wavelengths, meanwhile, allows astronomers to pinpoint the location of hot, luminous, newly formed stars. Together, the ALMA and Hubble observations provide a vital repository of data to astronomers studying star formation, as well as laying the groundwork for future science with the NASA/ESA/CSA James Webb Space Telescope.

Credits: ESA/Hubble & NASA, J. Lee and the PHANGS-HST Team; CC BY 4.0

Some of the most stunning views of our sky occur at sunset, when sunlight pierces the clouds, creating a mixture of bright and dark rays formed by the clouds’ shadows and the beams of light scattered by the atmosphere. Astronomers studying the nearby galaxy IC 5063 are tantalized by a similar effect in this new image from the NASA/ESA Hubble Space Telescope. In this case, a collection of narrow bright rays and dark shadows is seen beaming out of the blazingly bright center of the active galaxy, shooting across at least 36,000 light-years.

Astronomers have traced the rays back to the galaxy’s core, the location of an active supermassive black hole. The black hole is feeding on infalling material, producing a powerful gusher of light from superheated gas near it. Although the researchers have developed several plausible theories for the lightshow, the most intriguing idea suggests that the shadows are being cast into space by an inner tube-shaped ring, or torus, of dusty material surrounding the black hole.

IC 5063 resides 156 million light-years from Earth.

Credits: NASA, ESA, and W.P. Maksym (CfA); CC BY 4.0

An orange glow radiates from the centre of NGC 1792, the heart of this stellar forge. Captured by the NASA/ESA Hubble Space Telescope, this intimate view of NGC 1792 gives us some insight into this galactic powerhouse. The vast swathes of tell-tale blue seen throughout the galaxy indicate areas that are full of young, hot stars, and it is in the shades of orange, seen nearer the centre, that the older, cooler stars reside.

Nestled in the constellation of Columba (The Dove), NGC 1792 is both a spiral galaxy, and a starburst galaxy. Within starburst galaxies, stars are forming at comparatively exorbitant rates. The rate of star formation can be more than 10 times faster in a starburst galaxy than in the Milky Way. When galaxies have a large resevoir of gas, like NGC 1792, these short lived starburst phases can be sparked by galactic events such as mergers and tidal interactions. One might think that these starburst galaxies would easily consume all of their gas in a large forming event. However, supernova explosions and intense stellar winds produced in these powerful starbursts can inject energy into the gas and disperse it. This halts the star formation before it can completely deplete the galaxy of all its fuel. Scientists are actively working to understand this complex interplay between the dynamics that drive and quench these fierce bursts of star formation.

Credits: ESA/Hubble & NASA, J. Lee; CC BY 4.0

Acknowledgement: Leo Shatz

The ESA/NASA Solar and Heliospheric Observatory (SOHO) has been observing the Sun for 25 years. In that time, SOHO has observed two of the Sun’s 11-year sunspot cycles, as solar activity waxes and wanes. This montage of 25 images captured by the spacecraft’s Extreme Ultraviolet Imaging Telescope provides a snapshot of the changing face of our Sun. The individual images show gas with a temperature of about two million degrees Celsius in the Sun’s atmosphere, or corona, which extends millions of kilometres from the Sun. The brightest images occur around the time of solar maximum, when the Sun’s magnetic field is strongest and highly dynamic, changing its configuration and releasing energy into space.

View this image as an animated gif

Credits: SOHO (ESA & NASA)

This image, taken with the NASA/ESA Hubble Space Telescope, depicts a special class of star-forming nursery known as Free-floating Evaporating Gaseous Globules, or frEGGs for short. This object is formally known as J025157.5+600606.

When a massive new star starts to shine while still within the cool molecular cloud from which it formed, its energetic radiation can ionise the cloud’s hydrogen and create a large, hot bubble of ionised gas. Amazingly, located within this bubble of hot gas around a nearby massive star are the frEGGs: dark compact globules of dust and gas, some of which are giving birth to low-mass stars. The boundary between the cool, dusty frEGG and the hot gas bubble is seen as the glowing purple/blue edges in this fascinating image.

In July 2020 a previous ESA/Hubble Picture of the Week, of J025027.7+600849, featured another frEEG.

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

Terzan 1 is a globular cluster that lies about 22,000 light-years from Earth in the constellation Scorpius. It is one of 11 globular clusters that were discovered by the Turkish-Armenian astronomer Agop Terzan between 1966 and 1971 when he was working in France, based mostly at Lyon Observatory.

Somewhat confusingly, the 11 Terzan globular clusters are numbered from Terzan 1 to Terzan 12. This is due to an error made by Terzan in 1971, when he rediscovered Terzan 5 — a cluster he had already discovered and reported back in 1968 — and named it Terzan 11. He published its discovery alongside those of Terzan 9, 10 and 12. He quickly realised his mistake, and attempted to have Terzan 12 renamed as Terzan 11. Unfortunately, he did not make it clear that Terzan 5 and Terzan 11 were one and the same, although another astronomer, Ivan Robert King, did publish a note to try and clear up the confusion. Nowadays, most papers recognise the original Terzan 5 and Terzan 12, and accept the oddity that there is no Terzan 11. There have, however, been instances of confusion in the scientific literature over the past few decades.

Terzan 1 is not a new target for Hubble — an image of the cluster was released back in 2015, taken by Hubble’s Wide Field Planetary Camera 2 (WFPC2). That instrument was replaced by the Wide Field Camera 3 (WFC3) during the 2009 Hubble servicing mission. WFC3 has both superior resolving power and a wider field of view than WFPC2, and the improvement is obvious in this fantastically detailed image.

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

This intriguing observation from the NASA/ESA Hubble Space Telescope shows a gravitationally lensed galaxy with the long-winded identification SGAS J143845+145407. Gravitational lensing has resulted in a mirror image of the galaxy at the centre of this image, creating a captivating centrepiece.

Gravitational lensing occurs when a massive celestial body — such as a galaxy cluster — causes a sufficient curvature of spacetime for the path of light around it to be visibly bent, as if by a lens. Appropriately, the body causing the light to curve is called a gravitational lens, and the distorted background object is referred to as being "lensed". Gravitational lensing can result in multiple images of the original galaxy, as seen in this image, or in the background object appearing as a distorted arc or even a ring. Another important consequence of this lensing distortion is magnification, allowing astronomers to observe objects that would otherwise be too far away or too faint to be seen.

Hubble has a special flair for detecting lensed galaxies. The telescope's sensitivity and crystal-clear vision allow it to see faint and distant gravitational lenses that cannot be detected with ground-based telescopes because of the blurring effect of Earth's atmosphere. Hubble was the first telescope to resolve details within lensed images of galaxies, and is capable of imaging both their shape and internal structure.

This particular lensed galaxy is from a set of Hubble observations that take advantage of gravitational lensing to peer inside galaxies in the early Universe. The lensing reveals details of distant galaxies that would otherwise be unobtainable, and this allows astronomers to determine star formation in early galaxies. This in turn gives scientists a better insight into how the overall evolution of galaxies has unfolded.

Credits: ESA/Hubble & NASA, J. Rigby; CC BY 4.0

This image shows the globular cluster NGC 6380, which lies around 35 000 light-years from Earth, in the constellation Scorpio (The Scorpion). The very bright star at the top of the image is HD 159073, which is only around 4000 light-years from Earth, making it a much nearer neighbour to Earth than NGC 6380. This image was taken with Hubble’s Wide Field Camera 3 (WFC3), which, as its name suggests, has a wide field of view, meaning that it can image relatively large areas of the sky in enormous detail.

NGC 6380 is not a particularly exciting name, but it indicates that this cluster is catalogued in the New General Catalogue (NGC), which was originally compiled in 1888. This cluster has, however, been known by many other names. It was originally discovered by James Dunlop in 1826, and he rather immodestly named it Dun 538. Eight years later, in 1834, it was independently rediscovered by John Herschel and he (similarly immodestly) went on to name it H 3688. The cluster was re-rediscovered in 1959 in Paris by Pişmiş, who catalogued it as Tonantzintla 1 — and who, to continue the pattern, also referred to it as Pişmiş 25. In addition to its colourful history of rediscovery, up until the 1950s NGC 6380 was thought to be an open cluster. It was A. D. Thackeray who realised that it was in fact a globular cluster. Nowadays, this cluster is reliably recognised in widely available catalogues as a globular cluster, and referred to simply as NGC 6380.

Credits: ESA/Hubble & NASA, E. Noyola; CC BY 4.0

A new image from the NASA/ESA/CSA James Webb Space Telescope reveals a remarkable cosmic sight: at least 17 concentric dust rings emanating from a pair of stars. Located just over 5000 light-years from Earth, the duo is collectively known as Wolf-Rayet 140. Each ring was created when the two stars came close together and their stellar winds (streams of gas they blow into space) met, compressing the gas and forming dust. The stars’ orbits bring them together about once every eight years; like the rings of a tree’s trunk, the dust loops mark the passage of time.

In addition to Webb’s overall sensitivity, its Mid-Infrared Instrument (MIRI) is uniquely qualified to study the dust rings. These rings are also called shells by astronomers because they are thicker and wider than they appear in the image. Webb’s science instruments detect infrared light, a range of wavelengths invisible to the human eye.

Contributed under both ESA and NASA leadership, Webb’s MIRI instrument detects the longest infrared wavelengths. This means that it can often see cooler objects – including the dust rings – than Webb’s other instruments can. MIRI’s spectrometer also revealed the composition of the dust, formed mostly from material ejected by a type of star known as a Wolf-Rayet star. A Wolf-Rayet star is born with at least 25 times more mass than our Sun and is nearing the end of its life, when it will likely explode as a supernova and then collapse into a black hole. Burning hotter than in its youth, a Wolf-Rayet star generates powerful winds that push huge amounts of gas into space. The Wolf-Rayet star in this particular pair may have shed more than half its original mass via this process.

Transforming gas into dust is somewhat like turning flour into bread. It requires specific conditions and ingredients. Hydrogen, the most common element found in stars, can’t form dust on its own. But because Wolf-Rayet stars shed so much mass, they also eject more complex elements typically found deep in a star’s interior, including carbon. The heavy elements in the wind cool as they travel into space and are then compressed where the winds from both stars meet, like when two hands knead dough.

Some other Wolf-Rayet systems form dust, but none is known to make rings like Wolf-Rayet 140 does. The unique ring pattern forms because the orbit of the Wolf-Rayet star in WR 140 is elongated, not circular. Only when the stars come close together – about the same distance between Earth and the Sun – and their winds collide is the gas under sufficient pressure to form dust. With circular orbits, Wolf-Rayet binaries can produce dust continuously.

The science team thinks WR 140’s winds also swept the surrounding area clear of residual material they might otherwise collide with, which may be why the rings remain so pristine rather than smeared or dispersed. There are likely even more rings that have become so faint and dispersed, not even Webb can see them in the data.

Wolf-Rayet stars may seem exotic compared to our Sun, but they may have played a role in star and planet formation. When a Wolf-Rayet star clears an area, the swept-up material can pile up at the outskirts and become dense enough for new stars to form. There is some evidence the Sun formed in such a scenario.

Using data from MIRI’s Medium Resolution Spectroscopy mode, the new study provides the best evidence yet that Wolf-Rayet stars produce carbon-rich dust molecules. What’s more, the preservation of the dust shells indicates that this dust can survive in the hostile environment between stars, going on to supply material for future stars and planets. The catch is that while astronomers estimate that there should be at least a few thousand Wolf-Rayet stars in our galaxy, only about 600 have been found to date.

These results have been published today in Nature Astronomy.

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

[Image Description: The background of this Webb image of star Wolf-Rayet 140 is black. A pair of bright stars dominates the centre of the image, with at least 17 pink-orange concentric dust rings emanating from them. Throughout the scene are a range of distant galaxies, the majority of which are very tiny and red, appearing as splotches.]

Credits: NASA/ESA/CSA/STScI/JPL-Caltech; CC BY 4.0

The largest antenna ever tested in ESA’s Hertz radio frequency test chamber is this 5-m diameter transponder antenna, which will operate down on the ground to help calibrate the Biomass mission, which will chart all the forests on Earth.

“This is a particularly challenging test campaign both in terms of the size of the antenna and the very low P-band frequency that Biomass will be using, which allows it to pierce through forest canopies to acquire individual trees,” explains ESA antenna engineer Luis Rolo, overseeing the test campaign.

“Usually when we test a large satellite here, its antenna is significantly smaller, typically between 0.5 and 2 metres across. But this entire structure is a radiating antenna in its own right, its sides coming near to the chamber walls.

“What this means is that the testing process highlight some aspects of the chamber we’ve never seen before, even after many years of testing. But we’ve come up with a measurement method involving multiple acquisitions from different spots within the chamber, combined carefully to subtract such environmental effects, yielding very accurate results.”

Part of ESA’s technical heart in the Netherlands, the metal-walled ‘Hybrid European Radio Frequency and Antenna Test Zone’ chamber is shut off from all external influences. Its internal walls are studded with radio-absorbing ‘anechoic’ foam pyramids, allowing radio-frequency testing without any distorting reflections.

Its name starts with ‘Hybrid’ because the chamber can assess radio signals from antennas both in localised ‘near-field’ terms or else on a ‘far-field’ basis, as if the signal has crossed thousands of kilometres of space.

Due to be launched next year, Biomass will deploy a massive 12-m diameter reflector to harness P-band radar signals in order to perform a five-year census of all Earth's trees.

Based in Australia, this transponder will be integrated onto a mobile positioning system inside a protective radome, allowing it to track the Biomass satellite moving across the sky. The transponder antenna will reflect radar signals from Biomass back to it, to help confirm the mission is operating optimally. The transponder was developed and built by Italian company IDS.

Credits: ESA-SJM Photography

The Copernicus Sentinel-2 mission takes us over Batura Glacier – one of the largest and longest glaciers in the world, outside of the polar regions.

Located in the upper Hunza Valley, in the Gilgit-Baltistan region of Pakistan, the Batura Glacier is visible in the centre of the image and is approximately 57 km long. It flows from west to east and feeds the Hunza River in north Pakistan, then joins the Gilgit and Naltar Rivers before it flows into the Indus River.

The lower portions of the Batura Glacier feature a grey sea of rocks and gravelly moraine (an accumulation of rocks and sediment carried down by the glacier often caused by avalanches). The glacier has a mean ice thickness of around 150 m, with the lower parts of the glacier holding most of its mass.

This false-colour composite image uses the near-infrared channel of the Copernicus Sentinel-2 mission to highlight vegetation, which appears in red. Batura is bordered by several villages and pastures with herds of sheep, goats and cows where roses and juniper trees are quite common. In the upper-right of the image, pockets of cultivated vegetation alongside the Gilgit and Hunza rivers can be spotted.

Batura Glacier is located just north of the Batura Muztagh, a sub-range of the Karakoram mountain range, which includes the massifs of the Batura Sar, the 25th highest mountain on Earth standing at 7795 m, and Passu Sar at 7478 m.

Glacier shrinkage is a prominent sign of ongoing climate change. However, unlike many glaciers around the world, the glaciers residing in the mountain ranges in Karakoram are not responding to global warming. Their retreating is less than the global average, and in some cases, are either stable or growing. This anomalous behaviour of the region’s glaciers has been coined the ‘Karakoram Anomaly’.

Scientists typically measure the motions of glaciers with ground-based measurements. Because of the rugged terrain and challenges involved in field studies, long-term ground observational data on Karakoram is sparse. Satellites can help monitor changes in glacier mass, extents, trace area and length of glacier changes through time and derive surface velocity. Learn more about how Copernicus Sentinel-2 can help enhance glacier monitoring.

This image, captured on 13 August 2021, is also featured on the Earth from Space video programme.

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

Saturn’s moon Titan is enveloped in a thick atmosphere, but through the infrared eyes of the international Cassini mission, the moon’s myriad surface features are revealed in this exquisite global mosaic.

Observing the surface of Saturn’s largest moon, Titan, in visible light is difficult due to the globe-enshrouding haze that envelops the moon. On 14 January 2005, the mystery as to what lay beneath the thick atmosphere was revealed as ESA’s Huygens probe – carried to Titan by Cassini – made the first successful landing on a world in the outer Solar System. During the two-and-a-half hour descent under parachute, features that looked remarkably like shore lines and river systems on Earth appeared from the haze. But rather than water, with surface temperatures of around –180ºC, the fluid involved here is methane, a simple organic compound that also contributes to the moon’s obscuring atmosphere.

Thanks to Cassini, which studied Saturn and its rings and moons for thirteen years, Titan was extensively mapped and analysed. One result is this stunning sequence of images created using data acquired by Cassini’s Visual and Infrared Mapping Spectrometer (VIMS), whose infrared observations peered through Titan’s atmosphere, complementing the views obtained by Huygens during descent and on the surface. The maps combine data from the multitude of different observations made under a wide variety of illumination and viewing conditions over the course of the mission, stitched together in a seamless mosaic to provide the best representation of Titan’s surface to date.

The colours reflect variations in materials on the moon’s surface. For example, the moon’s equatorial dune fields appear a consistent brown colour, while bluish and purple hues may indicate materials enriched in water ice.

The image was first published in July 2018 – read more here about how the image was created, and enjoy a video featuring further stunning visuals here. The complete Cassini VIMS data archive of Saturn’s satellites is available here.

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-Caltech/University of Nantes/University of Arizona

A cataclysmic cosmic collision takes centre stage in this Picture of the Week. The image features the interacting galaxy pair IC 1623, which lies around 275 million light-years away in the constellation Cetus (The Whale). The two galaxies are in the final stages of merging, and astronomers expect a powerful inflow of gas to ignite a frenzied burst of star formation in the resulting compact starburst galaxy.

This interacting pair of galaxies is a familiar sight; Hubble captured IC 1623 in 2008 using two filters at optical and infrared wavelengths using the Advanced Camera for Surveys. This new image incorporates new data from Wide Field Camera 3, and combines observations taken in eight filters spanning infrared to ultraviolet wavelengths to reveal the finer details of IC 1623. Future observations of the galaxy pair with the NASA/ESA/CASA James Webb Space Telescope will shed more light on the processes powering extreme star formation in environments such as IC 1623.

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

Two merging galaxies in the VV689 system — nicknamed the Angel Wing —feature in this image from the NASA/ESA Hubble Space Telescope. Unlike chance alignments of galaxies which only appear to overlap as seen from our vantage point on Earth, the two galaxies in VV689 are in the midst of a collision. The galactic interaction has left the VV689 system almost completely symmetrical, giving the impression of a vast set of galactic wings.

This angelic image comes from a set of Hubble observations inspecting the highlights of the Galaxy Zoo citizen science project. This crowdsourced astronomy project relied on hundreds of thousands of volunteers to classify galaxies and help astronomers wade through a deluge of data from robotic telescopes. In the process, volunteers discovered a rogues’ gallery of weird and wonderful galaxy types, some of which had not previously been studied. A similar, ongoing project called Radio Galaxy Zoo is using the same crowdsourcing approach to locate supermassive black holes in distant galaxies.

Noteworthy objects from both projects were chosen for detailed follow-up observations with Hubble’s Advanced Camera for Surveys. In keeping with the crowdsourced nature of the Galaxy Zoo project, the targets for follow-up observations with Hubble were chosen via roughly 18 000 votes cast by the public. The selected targets include ring-shaped galaxies, unusual spirals, and a striking selection of galaxy mergers such as VV689.

Credits: ESA/Hubble & NASA, W. Keel.; CC BY 4.0

Acknowledgement: J. Schmidt

The Copernicus Sentinel-2 mission takes us over the sediment-stained waters in Laizhou Bay, located on the southern shores of the Bohai Sea, on the east coast of mainland China.

The bay is the smallest of three main bays of the Bohai Sea, and is named after the city of Laizhou, visible to the east. Large quantities of sediment carried by the Yellow River, visible in the left of the image, discolour the waters of the bay and appear turquoise. This sediment can be seen throughout the waters in this image, even far from the coast.

The Yellow River is China’s second longest river, with a length of over 5400 km, and is surpassed only by the Yangtze River. The river rises in the Bayan Har Mountains in Western China and flows through nine provinces before emptying into the Laizhou Bay. Its drainage basin is the third largest in the country, with an area of around 750 000 sq km.

The river is estimated to carry 1.6 billion tonnes of silt annually, carrying the majority to the sea. Owing to this heavy load of silt, the Yellow River deposits soil in stretches, ultimately elevating the river bed. Excessive sediment deposits have raised the river bed several metres above the surrounding ground, sometimes causing damaging floods.

On the southern coast of Laizhou Bay, in the bottom of the image, flooded fields are visible and are most likely artificial fish farms. The city of Dongying, home to the second largest oilfield in China, is visible in the left of the image.

This image was processed in a way that included the near-infrared channel, which makes vegetation appear bright red. The lush vegetation can be distinguished from the brown fields in the image, which are unharvested or not yet fully grown.

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

This image, acquired on 26 February 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

The pieces are stacking up for the launch of Artemis 1 mission around the Moon and back. The massive Space Launch Systems (SLS) rocket that will launch the first crewless test flight of the Orion spacecraft, powered by the European Service Module, is being integrated at the Vehicle Assemble Building at NASA’s Kennedy Space Center in Florida, USA.

Visible in this image are the twin solid fuel rocket boosters, now fully stacked atop the mobile launcher. The boosters will be mated with the rocket’s 65 m tall core stage that recently barged in to Florida aboard the Pegasus barge on 27 April after successful testing at NASA’s Stennis Space Center in Mississippi.

Once the rocket stages are ready to go, the Orion spacecraft and additional flight hardware are next up for integration.

Since our last Orion and the European Service Module update for Artemis I, the spacecraft has moved, from the NASA Kennedy Space Center’s Neil Armstrong Operations and Checkout facility, a few kilometres down the road to the Multi Payload Processing Facility. The names of these buildings give the game away. The first Orion spacecraft has been checked out and is ready for the next step on the road to space: processing for launch.

Fuelling was completed on 1 April, after which the system will be serviced in high pressure helium that serves as a pressurisation agent to the European Service Module propellant tanks, ensuring the correct pressure at the engine inlets.

Eventually, the spacecraft will be hoisted to the top of the fully stacked SLS rocket.

Read more updates on the Orion blog.

The European Service Module is ESA’s contribution to NASA’s Orion spacecraft that will send astronauts, including the first European, to the Moon and beyond. Follow Europe’s role in the mission here.

Credits: NASA – J. Blair

The Space Launch System (SLS) rocket with the Orion spacecraft aboard lifted off at 07:47 CEST from NASA’s Kennedy Space Center in Florida, USA on 16 November 2022.

The most powerful rocket ever built sent NASA’s Orion spacecraft and ESA’s European Service Module (ESM) to a journey beyond the Moon and back. No crew will be on board Orion this time, and the spacecraft will be controlled by teams on Earth.

ESM provides for all astronauts’ basic needs, such as water, oxygen, nitrogen, temperature control, power and propulsion.

Much like a train engine pulls passenger carriages and supplies power, the European Service Module will take the Orion capsule to its destination and back.

Credits: ESA - S. Corvaja

A view looking north to south of Egypt’s famous Giza Pyramid Complex, as seen by ESA’s Proba-1 minisatellite.

The smaller Pyramid of Menkaure is seen to towards the centre of the image, with the larger Pyramid of Khafre down and left of it, with the Great Pyramid of Giza – the largest and oldest of the three – below and left of that.

Three smaller pyramids are adjacent to the Pyramid Menkaure. The Giza Plateau sits on the edge of Cairo, fringed by suburbs.

The cubic-metre Proba-1 is the first in ESA’s series of satellites aimed at flight-testing new space technologies. It was launched on 22 October 2001 but is still going strong, having recently became the Agency’s longest-serving Earth-observing mission.

Proba-1’s main hyperspectral CHRIS imager is supplemented by this experimental High-Resolution Camera, acquiring black and white 5 m-resolution images.

Other innovations include what were then novel gallium-arsenide solar cells, the use of startrackers for gyroless attitude control, one of the first lithium-ion batteries – now the longest such item operating in orbit – and one of ESA’s first ERC32 microprocessors to run Proba-1’s agile computer.

For more background on Proba-1, read this celebration in the ESA bulletin.

Proba-1 led the way for the Sun-monitoring Proba-2 in 2009, the vegetation-tracking Proba-V in 2013 and the Proba-3 precise formation-flying mission planned for late 2020.

This image was acquired on 6 January 2018.

Credits: ESA

UGCA 307 hangs against an irregular backdrop of distant galaxies in this image from the NASA/ESA Hubble Space Telescope. The small galaxy consists of a diffuse band of stars containing red bubbles of gas that mark regions of recent star formation, and lies roughly 26 million light-years from Earth in the constellation Corvus. Appearing as just a small patch of stars, UGCA 307 is a diminutive dwarf galaxy without a defined structure — resembling nothing more than a hazy patch of passing cloud.

This image is part of a Hubble project to explore every known nearby galaxy, giving astronomers insights into our galactic neighbourhood. Before this set of observations, almost three quarters of nearby galaxies had been investigated by Hubble in enough detail to spot the brightest stars and build up an understanding of the stars populating each galaxy. This Hubble project set out to explore the remaining quarter of nearby galaxies by taking advantage of short gaps in Hubble’s observing schedule.

This crystal-clear image was captured by Hubble’s Advanced Camera for Surveys (ACS), which was installed on the telescope in 2002 during Servicing Mission 3B. Hubble’s vantage point in low Earth orbit means that it is above atmospheric turbulence, giving it a sharper view of the Universe. However, it is also close enough to Earth that astronauts could visit the telescope to repair and refurbish the telescope. In total, five Space Shuttle missions flew to Hubble and kept it at the forefront of astronomy by installing new instruments. The ACS replaced one of Hubble’s original instruments, the Faint Object Camera, which was built by ESA.

[Image description: A wide band of bluish light extends from the centre of the image to the right side. It is speckled with many tiny stars, and a few small, bright red bubbles of gas, identifying it as a galaxy. The background is black, and has small galaxies and stars spread around. Most are too small to distinguish, except for two oval-shaped galaxies, each having a hazy glow around a bright centre.]

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

Take away the clouds, bulk up the humans with suits and add an orange-red filter and this could be an image from a future mission to Mars.

The actual site, the Corona lava tube in Lanzarote, Spain, is closer than one might think to the Red Planet.

That’s why participants of ESA’s Pangaea course came here this week for the third session of their planetary geology training.

ESA astronaut Andreas Mogensen, ESA engineer Robin Eccleston and NASA astronaut Kathleen Rubins are this year’s students learning from geologists how to best explore the Moon and Mars right here on Earth.

Before ending up in one of Europe’s volcanic hotspots, Andreas, Kathleen and Robin learned how to describe geological sites, and how to classify rocks and identify traces of life during field trips to the Italian Dolomites and the Ries crater in Germany in September.

Lanzarote’s volcanic landscapes are exceptionally well-preserved, and the long history of geological activity make it a unique open-air museum. Here, basaltic lava flows resemble vast plains on the lunar maria and volcanoes are similar to those in some regions of Mars.

For an astronaut whose day job is the daily operations of the International Space Station at Mission Control in Houston, USA, Andreas admits that looking at rocks sounded kind of boring at first.

But in Lanzarote, Andreas and his crewmates were set loose on the Mars-like terrain to follow pre-planned geological investigation routes and analyse the mineralogy of the soil all while remaining in constant communication with the science and training teams with dedicated tools.

Now, Andreas has learned to see the rocks in a new light. “It’s intriguing to interpret the layers of the Earth where the rocks come from, and from there begin to understand the evolution of our planet,” he says.

Looking at rocks has led to an interesting three weeks for the astronaut, who would choose Mars as a destination for future spaceflight. Mars exploration might be in the distant horizon, but “still a fascinating place to visit,” he adds.

Pangaea – named after the ancient supercontinent – prepares the astronauts for geological expeditions to other planets. Trainees acquire skills and knowledge both in the field and in the classroom, tailored towards the needs of future planetary explorers.

Credits: ESA–A. Romeo

This jewel-bright Picture of the Week features the spiral galaxy NGC 2903. This image was captured using Hubble’s Advanced Camera for Surveys (ACS) and Wide Field Camera 3 (WFC3), which were installed on Hubble in 2002 and 2009 respectively. Interestingly, Hubble has observed this particular galaxy before, in 2001, when neither the ACS or the WFC3 had yet been installed. The 2021 image boasts higher resolution, which means that NGC 2903 is more finely detailed than in the 2001 image. The ACS and WFC2 collectively cover a wide range of ultraviolet, optical and infrared wavelengths, which means that the 2021 image also has superior wavelength coverage to that of its 20-year-old predecessor. The 2001 image was taken using the Wide Field Planetary Camera 2 (WFPC2), which was Hubble’s workhorse instrument from 1993 until 2009 when it was replaced by the WFC3.

Hubble has a long and fascinating history of crewed service missions, which were performed in order to correct for imperfections in Hubble’s mirror, to update Hubble’s technical systems, and to remove old instruments and install new ones. One of Hubble’s most remarkable features is it’s incredible longevity, and this would not have been possible with the great success of the servicing missions. The juxtaposition of the 2001 and 2021 images of NGC 2903 — both remarkable images for their time — highlights the value of a stable, accessible platform in space that can reliably collect data, not only year after year, but decade after decade.

Credits: ESA/Hubble & NASA, L. Ho, J. Lee and the PHANGS-HST Team; CC BY 4.0

A snap of ESA astronaut Thomas Pesquet during the second spacewalk to upgrade the International Space Station’s power system, taken by NASA astronaut Shane Kimbrough.

The duo performed the second extra vehicular activity to bolt in place and unfurl an IROSA, or ISS Roll-Out Solar Array, on Sunday 20 June.

The series of spacewalks last week was not without some challenges. During the first spacewalk on 16 June, Shane experienced a small technical problem in his spacesuit that required him to return to the airlock and restart his Display and Control Module. This module provides astronauts with continuous information on pressure, temperature and other vital data during a spacewalk.

Though the restart was successful and Shane was in no danger, it delayed the duo’s work, preventing them from completing installation of the first new solar array as planned.

The duo succeeded in taking the IROSA panel out of its storage area outside the Space Station and passed from spacewalker to spacewalker to the worksite. There the rolled arrays were secured. The spacewalk lasted 7 hours and 15 minutes.

During the second spacewalk, the duo unfolded, bolted and connected the wires. Then they hung out while the panels were unfurled, a sequence that lasted about 10 minutes.

Shane and Thomas then got ahead of the next spacewalk by preparing the next IROSA for installation before cleaning up the worksite and heading back to the airlock. This spacewalk lasted 6 hours and 28 minutes, with only a minor technical snag. Shane’s helmet lights and camera partially detached from his helmet but Thomas used some wire to reattach them as a temporary fix.

Mission planners are working on a third spacewalk on Friday June 25 to install the second pair of new solar arrays. This will go on the P6 truss’ 4B power channel, opposite the first new solar array.

Follow the action on ESA Web TV from 12:30 CEST (11:30 BST).

Thomas now has spent 26 hours and 15 minutes on spacewalks over his two missions on the International Space Station, Proxima and Alpha.

“It was probably the most impressive experience I’ve ever had but it was not easy,” says Thomas.

Credits: NASA–S. Kimbrough

Ariane 5 V243 ascends from the European Spaceport’s ELA-3 launch zone on its 100th flight, carrying a dual payload of the Horizons 3e and Azerspace-2/Intelsat 38 telecommunications satellites, 25 September 2018

Credits: ESA/CNES/Arianespace

In this image, the NASA/ESA Hubble Space Telescope captures a side-on view of NGC 3568, a barred spiral galaxy roughly 57 million light-years from the Milky Way in the constellation Centaurus. In 2014 the light from a supernova explosion in NGC 3568 reached Earth — a sudden flare of light caused by the titanic explosion accompanying the death of a massive star. Whilst most astronomical discoveries are the work of teams of professional astronomers, this supernova was discovered by amateur astronomers from the Backyard Observatory Supernova Search in New Zealand. Dedicated amateur astronomers often make intriguing discoveries — particularly of fleeting astronomical phenomena such as supernovae.

This Hubble observation comes from a hoard of data built up to pave the way for future science with the upcoming NASA/ESA/CSA James Webb Space Telescope. By combining ground-based observations with data from Hubble’s Advanced Camera for Surveys and Wide Field Camera 3, astronomers have built a treasure trove of data on the connections between young stars and the clouds of cold gas in which they form. One of Webb’s key science goals is to explore the life cycle of stars — particularly how and where stars are born. Since Webb observes at infrared wavelengths, it will be able to peer through the clouds of gas and dust in stellar nurseries and observe the fledgling stars within. Webb’s superb sensitivity will even allow astronomers to directly investigate faint protostellar cores — the earliest stages of star birth.

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

In the forests of the night lies a barred spiral galaxy called NGC 3583, imaged here by the NASA/ESA Hubble Space Telescope. This is a barred spiral galaxy with two arms that twist out into the Universe. This galaxy is located 98 million light-years away from the Milky Way. Two supernovae exploded in this galaxy, one in 1975 and another, more recently, in 2015.

There are a few different ways that supernova can form. In the case of these two supernovae, the explosions evolved from two independent binary star systems in which the stellar remnant of a Sun-like star, known as a white dwarf, was collecting material from its companion star. Feeding off of its partner, the white dwarf gorged on the material until it reached a maximum mass. At this point, the star collapsed inward before exploding outward in a brilliant supernova.

Two of these events were spotted in NGC 3583, and though not visible in this picture of the week, we can still marvel at the galaxy’s fearful symmetry.

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

This beautifully crisp icy scene was captured by the High Resolution Stereo Camera (HRSC) on ESA’s Mars Express on 19 May 2022 during orbit 23219.

The ground resolution is approximately 18 m/pixel and the image is centred at about 185°E/76°S. It was created using data from the nadir channel, the field of view aligned perpendicular to the surface of Mars, and the colour channels of the HRSC. North is to the right.

Read more

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

The mass of dust and bright swirls of stars in this image are the distant galaxy merger IC 2431, which lies 681 million light-years from Earth in the constellation Cancer. The NASA/ESA Hubble Space Telescope has captured what appears to be a triple galaxy merger in progress, as well as a tumultuous mixture of star formation and tidal distortions caused by the gravitational interactions of this galactic trio. The centre of this image is obscured by a thick cloud of dust — though light from a background galaxy can be seen piercing its outer extremities.

This image is from a series of Hubble observations investigating weird and wonderful galaxies found by the Galaxy Zoo citizen science project. Using Hubble’s powerful Advanced Camera for Surveys (ACS), astronomers took a closer look at some of the more unusual galaxies that volunteers had identified. The original Galaxy Zoo project was the largest galaxy census ever carried out, and relied on crowdsourcing time from more than 100 000 volunteers to classify 900 000 unexamined galaxies. The project achieved what would have been years of work for a professional astronomer in only 175 days, and has led to a steady stream of similar astronomical citizen science projects. Later Galaxy Zoo projects have included the largest ever studies of galaxy mergers and tidal dwarf galaxies, as well as the discovery of entirely new types of compact star-forming galaxies.

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

Acknowledgement: J. Schmidt

Space Science image of the week:

A gigantic ribbon of hot gas bursts upwards from the Sun, guided by a giant loop of invisible magnetism. This remarkable image was captured on 27 July 1999 by SOHO, the Solar and Heliospheric Observatory. Earth is superimposed for comparison and shows that from top to bottom the loop of gas, or prominence, extends about 35 times the diameter of our planet into space.

A prominence is an extension of gas that arches up from the surface of the Sun. Prominences are sculpted by magnetic fields that are generated inside the Sun, and then burst through the surface, propelling themselves into the solar atmosphere.

The Sun is predominantly made of plasma – an electrified gas of electrons and ions. Being electrically charged, the ions respond to magnetic fields. So when the magnetic loops reach up into the solar atmosphere, huge streams of plasma are attracted to fill them, creating the prominences that can last for weeks or months.

Spectacular prominences like this one are not particularly common, a few being detected each year. When they start to collapse, mostly the gas ‘drains’ down the magnetic field lines back into the Sun. Occasionally, however, they become unstable and release their energy into space. These eruptive prominences fling out a huge quantity of plasma that solar physicists call a coronal mass ejection. Solar flares are also associated with coronal mass ejections.

If this plasma hits Earth it can disrupt satellites, power grids and communications. It also causes the aurora to shine in the polar skies.

Taken by SOHO’s ultraviolet telescope, this image shows ionised helium at a temperature of about 70 000ºC.

A version of the image without the Earth for comparison can be found here.

Credit: SOHO (ESA & NASA)

Kolkata, formerly Calcutta, is featured in this optical image, captured by the Copernicus Sentinel-2 mission.

Zoom in to explore this image at its full 10 m resolution or click on the circles to learn more about the features in it.

Kolkata, visible in grey in the centre of the image, is one of India’s largest cities with over 14 million inhabitants. Part of the neighbouring country Bangladesh is also visible in the right.

Kolkata lies on the Hooghly River, which can be seen cutting through the city. The different shades of brown and blue in the water are likely due to the high concentration of sediments. Vast agricultural and aquaculture fields can also be seen, including rice fields and fish ponds, which are distinguishable by their rectangular shapes and the presence of water, particularly in the right side of the image.

The Sundarbans National Park is visible in dark green in the bottom right corner. This protected national reserve, a designated UNESCO World Heritage Site, is home to Bengal tigers and hosts a vast mangrove forest.

Copernicus Sentinel-2 is a two-satellite mission designed to map differences in land cover to understand Earth’s landscape, as well as monitor changes over time. As cities continue to expand, Sentinel-2 can also be used to improve urban and rural planning.

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

The penultimate sunset at Concordia research station in Antarctica marks the beginning of a very exciting time for the 12-member crew: the coming of Antarctic night and the winter-over.

ESA sponsored medical doctor Hannes Hagson and his crew mates are finally embarking on their ‘real’ mission in Antarctica: living and work in isolation for six months in the name of spaceflight research.

The Italian-French outpost Concordia is located 3233 m above sea level where temperatures can drop to –80°C in the complete frozen darkness outside. The sun disappears behind the horizon for four months. No supplies or people can be flown in during the winter months; and the high altitude causes the crew to experience chronic hypobaric hypoxia or lack of oxygen in the brain.

These conditions are as close to living on another planet as humans can get on Earth.

For this reason, Hannes is facilitating biomedical experiments on himself and his crewmates to understand how humans cope with living in extreme isolation. From sleep studies to gut health measurements to mindful practices, the crew are poked and prodded to help researchers understand and overcome the challenges extreme environments, like space, pose to present and future explorers.

This image was taken by Hannes on 3 May. The last full sunset took place the day after but appeared only as a thin sliver in the sky.

Follow Hannes during his winter-over on the Chronicles from Concordia blog.

Credits: ESA/IPEV/PNRA-H. Hagson

Looking deep into the Universe, the NASA/ESA Hubble Space Telescope catches a passing glimpse of the numerous arm-like structures that sweep around this barred spiral galaxy, known as NGC 2608. Appearing as a slightly stretched, smaller version of our Milky Way, the peppered blue and red spiral arms are anchored together by the prominent horizontal central bar of the galaxy.

In Hubble photos, bright Milky Way stars will sometimes appear as pinpoints of light with prominent lens flares. A star with these features is seen in the lower right corner of the image, and another can be spotted just above the pale centre of the galaxy. The majority of the fainter points around NGC 2608, however, lack these features, and upon closer inspection they are revealed to be thousands of distant galaxies. NGC 2608 is just one among an uncountable number of kindred structures.

Similar expanses of galaxies can be observed in other Hubble images such as the Hubble Deep Field which recorded over 3000 galaxies in one field of view.

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

Some of the most dramatic events in the Universe occur when certain stars die — and explode catastrophically in the process.

Such explosions, known as supernovae, mainly occur in a couple of ways: either a massive star depletes its fuel at the end of its life, become dynamically unstable and unable to support its bulk, collapses inwards, and then violently explodes; or a white dwarf in an orbiting stellar couple syphons more mass off its companion than it is able to support, igniting runaway nuclear fusion in its core and beginning the supernova process. Both types result in an intensely bright object in the sky that can rival the light of a whole galaxy.

In the last 20 years the galaxy NGC 5468, visible in this image, has hosted a number of observed supernovae of both the aforementioned types: SN 1999cp, SN 2002cr, SN2002ed, SN2005P, and SN2018dfg. Despite being just over 130 million light-years away, the orientation of the galaxy with respect to us makes it easier to spot these new ‘stars’ as they appear; we see NGC 5468 face on, meaning we can see the galaxy’s loose, open spiral pattern in beautiful detail in images such as this one from the NASA/ESA Hubble Space Telescope.

Credits: ESA/Hubble & NASA, W. Li et al.; Acknowledgements: Judy Schmidt (Geckzilla); CC BY 4.0

Internal research fellow Johanna Wessing performing X-ray photoelectron spectroscopy of the topmost skin of a candidate material for space.

This powerful technique enables the analysis of surface structures and composition to a depth of just a few nanometres – a nanometre being a billionth of a metre, or, typically, a few dozen individual atoms.

Exposure to space can be bad for the health of many substances, combining prolonged exposure to vacuum with intense sunlight, radiation and temperature extremes. Its surface is where a material meets the outside environment so this kind of inspection is important: variations in surface chemistry can substantially alter a material’s overall behaviour.

X-ray photoelectron spectroscopy provides not only the unique fingerprint of an element but also its chemical state and information about the nature of surrounding atoms. In addition this process can also check whether a material is truly clean, right down to atomic scale, to avoid introducing any contamination.

The X-ray Photoelectron Spectrometer is one of a comprehensive suite of analysis tools at ESA’s Materials and Electrical Components Laboratory at the ESTEC technical centre in Noordwijk, the Netherlands.

Credits: ESA-Remedia

The NASA/ESA Hubble Space Telescope snapped this image of the young comet P/2019 LD2 as it orbits near Jupiter's captured ancient asteroids, which are called Trojans. This icy object is the first comet astronomers have spotted near the Trojan population.

The Hubble view reveals a 640,000-kilometer-long tail of dust and gas flowing from the wayward comet's bright solid nucleus. The tail is evidence that the icy object is active, despite its great distance from the faint Sun. The tail could be driven by the release of carbon monoxide and carbon dioxide. These volatiles do not need much sunlight to heat their frozen form and convert them to gas.

The wayfaring comet was discovered in early June 2019 by the University of Hawaii's Asteroid Terrestrial-impact Last Alert System (ATLAS) telescope.

The icy interloper is most likely one of the latest members of the so-called "bucket brigade" of comets to travel inward toward the Sun after getting kicked out of its frigid home in the Kuiper belt through interactions with the outermost giant planet, Neptune.

Located on the outskirts of our solar system, the Kuiper belt is a haven of icy, leftover debris from our planets' construction 4.6 billion years ago.

The vagabond comet is a temporary resident among Jupiter's asteroids. Computer simulations show that the unexpected guest will have a close encounter with Jupiter in roughly another two years. The massive planet will boot the comet toward the inner solar system.

This Hubble visible-light image is a combination of exposures taken April 1 and May 8, 2020, with the Wide Field Camera 3.

Credits: NASA, ESA, STScI, B. Bolin (IPAC/Caltech); CC BY 4.0

The jellyfish galaxy JO175 appears to hang suspended in this image from the NASA/ESA Hubble Space Telescope. This galaxy lies over 650 million light-years from Earth in the appropriately-named constellation Telescopium, and was captured in crystal-clear detail by Hubble’s Wide Field Camera 3. A handful of more distant galaxies are lurking throughout the scene, and a bright four-pointed star lies to the lower right side.

Jellyfish galaxies get their unusual name from the tendrils of star-forming gas and dust that trail behind them, just like the tentacles of a jellyfish. These bright tendrils contain clumps of star formation and give jellyfish galaxies a particularly striking appearance. Unlike their ocean-dwelling namesakes, jellyfish galaxies make their homes in galaxy clusters, and the pressure of the tenuous superheated plasma that permeates these galaxy clusters is what draws out the jellyfish galaxies’ distinctive tendrils.

Hubble recently completed a deep dive into jellyfish clusters, specifically the star-forming clumps of gas and dust that stud their tendrils. By studying the origins and fate of the stars in these clumps, astronomers hoped to better understand the processes underpinning star formation elsewhere in the Universe. Interestingly, their research suggests that star formation in the discs of galaxies is similar to star formation in the extreme conditions found in the tendrils of jellyfish galaxies.

[Image Description: A spiral galaxy. Its spiral arms are studded with many pink spots, especially around the top of the galaxy. One arm is sticking out below the galaxy. From it and around the bottom of the galaxy, faint gas streams away, while little gas is visible above the galaxy. The galaxy is quite small in the centre of a dark background, where a few smaller galaxies of various shapes and sizes hang.]

Credits: ESA/Hubble & NASA, M. Gullieuszik and the GASP team; CC BY 4.0

This Picture of the Week shows an open cluster known as NGC 2164, which was first discovered in 1826 by a Scottish astronomer named James Dunlop. NGC 2164 is located within one of the Milky Way galaxy's closest neighbours — the satellite galaxy known as the Large Magellanic Cloud. The Large Magellanic cloud is a relatively small galaxy that lies about 160 000 light-years from Earth. It is considered a satellite galaxy because it is gravitationally bound to the Milky Way. In fact, the Large Magellanic cloud is on a very slow collision course with the Milky Way — it’s predicted that they will collide 2.4 billion years from now.

The Large Magellanic Cloud only contains about one hundredth as much mass as the Milky Way, but it still contains billions of stars. The open cluster NGC 2164 is in good company in the Large Magellanic Cloud — the satellite galaxy is home to roughly 700 open clusters, alongside about 60 globular clusters. This image of NGC 2164 was taken by the NASA/ESA Hubble Space Telescope’s Wide Field Camera 3 (WFC3), which has previously imaged many other open clusters, including NGC 330 and Messier 11.

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

This image depicts a swirling spiral galaxy named NGC 2906.

The blue speckles seen scattered across this galaxy are massive young stars, which emit hot, blue-tinged radiation as they burn through their fuel at an immense rate. The swathes of orange are a mix of older stars that have swollen and cooled, and low-mass stars that were never especially hot to begin with. Owing to their lower temperatures, these stars emit a cooler, reddish, radiation.

This image of NGC 2906 was captured by the NASA/ESA Hubble Space Telescope’s Wide Field Camera 3, an instrument installed on Hubble in 2009 during the telescope’s fourth servicing mission. Hubble observed this galaxy on the hunt for fading light from recent, nearby occurrences of objects known as supernovae.

Credits: ESA/Hubble & NASA, A Filippenko; CC BY 4.0

A notable feature of most spiral galaxies is the multitude of arching spiral arms that seemingly spin out from the galaxy’s centre. In this image, taken with the NASA/ESA Hubble Space Telescope, the stunning silvery-blue spiral arms of the galaxy NGC 4848 are observed in immense detail. Not only do we see the inner section of the spiral arms containing hundreds of thousands of young, bright, blue stars, but Hubble has also captured the extremely faint wispy tails of the outer spiral arms.

This wispy barred spiral galaxy was first discovered in 1865 by the German astronomer Heinrich Louis d’Arrest. In his career, Heinrich also notably discovered the asteroid 76 Freia and many other galaxies and he also contributed to the discovery of Neptune.

If you are situated in the Northern Hemisphere with a large telescope, you might just be able to observe the ghost-like appearance of this faint galaxy within faint constellation of Coma Berenices (Berenice’s Hair).

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

Located in the constellation of Virgo (The Virgin), around 50 million light-years from Earth, NGC 4535 is truly a stunning sight to behold. Despite the incredible quality of this image, taken from the NASA/ESA Hubble Space Telescope, NGC 4535 has a hazy, somewhat ghostly, appearance when viewed from a smaller telescope. This led amateur astronomer Leland S. Copeland to nickname NGC 4535 the “Lost Galaxy” in the 1950s.

The bright colours in this image aren’t just beautiful to look at, as they actually tell us about the population of stars within this barred spiral galaxy. The bright blue-ish colours, seen nestled amongst NGC 4535’s long, spiral arms, indicate the presence of a greater number of younger and hotter stars. In contrast, the yellower tones of this galaxy’s bulge suggest that this central area is home to stars which are older and cooler.

This galaxy was studied as part of the PHANGS survey, which aims to clarify many of the links between cold gas clouds, star formation, and the overall shape and other properties of galaxies. On 11 January 2021 the first release of the PHANGS-HST Collection was made publicly available.

Credits: ESA/Hubble & NASA, J. Lee and the PHANGS-HST Team; CC BY 4.0

Space Science image of the week:

The international Cassini mission is drawing to a close in spectacular style: diving between Saturn and its innermost rings and exploring uncharted territory like never before.

The final set of five dives even dips the spacecraft into the top of Saturn’s atmosphere, giving Cassini’s instruments the chance to make the first direct sampling of the planet, studying its chemical composition and analysing its temperature at different altitudes. The dives will also provide close-up images of the planet’s atmospheric features, including its polar vortex and aurora.

Cassini is just completing its third of such atmospheric ‘dips’, and towards the end of the final orbit, will make a distant flyby of Titan, at 119 049 km on 11 September. But this will still be close enough to set Cassini on its final trajectory into the planet’s atmosphere, concluding its 13-year odyssey in the Saturn system.

Additional details of the mission’s grand finale will be presented by NASA tomorrow in a dedicated media briefing, scheduled for 18:00 GMT / 20:00 CEST.

The image shown here was captured during an earlier dive between the planet and its rings, at a distance of approximately 1.1 million kilometers from Saturn on 13 May. It shows the thin sliver of Saturn’s 86 km-wide moon Prometheus lurking near ghostly structures in Saturn's narrow F-ring. Many of the narrow ring’s faint and wispy features result from its gravitational interactions with Prometheus.

Most of the small moon’s surface is in darkness because of the viewing geometry: Cassini was positioned behind Saturn and Prometheus with respect to the Sun, looking towards the moon’s dark side and just a bit of the moon’s sunlit northern hemisphere. Detail in the sunlit side of the rings shows a distinct difference in brightness between the outermost section of Saturn’s A ring (left of centre) and the rest of the ring, interior to the Keeler Gap (lower left).

The image was first released on 7 August 2017.

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

Credit: NASA/JPL-Caltech/Space Science Institute

This Copernicus Sentinel-3 image shows the dust storm that has covered Beijing in the last few days. Taken on 15 March 2021. It shows a thick layer of dust/sand moving towards China from the west

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

Combining artificial intelligence with many keen human eyes, astronomers have found 1701 new asteroid trails in archival data from the NASA/ESA Hubble Space Telescope, consisting of more than 37 000 images that span two decades. The project reflects both Hubble’s value to scientists as an asteroid hunter and how the public can effectively contribute to citizen science initiatives.

On International Asteroid Day in June 2019 an international group of astronomers launched the Hubble Asteroid Hunter, a citizen science project to identify asteroids in archival Hubble data. The initiative was developed by researchers and engineers at the European Science and Technology Centre (ESTEC) and the European Space Astronomy Centre’s Science Data Centre (ESDC), in collaboration with the Zooniverse platform, the world’s largest and most popular citizen science platform, and Google.

The astronomers collectively identified more than 37 000 composite images taken between April 2002 and March 2021 with Hubble’s ACS and WFC3 instruments. With a typical observation time of 30 minutes, asteroid trails appear as curved lines or streaks in these images. Over 11 400 members of the public classified and analysed these images. More than 1000 trails were identified, providing a training set for an automated algorithm based on artificial intelligence. The combination of citizen science and AI resulted in a final dataset containing 1701 trails in 1316 Hubble images. Project participants also tagged various other astronomical objects, such as gravitational lenses, galaxies and nebulae. Volunteers discussed their findings and sought assistance from scientists and other participants via the project’s forum.

Roughly one third of the asteroid trails seen could be identified and attributed to known asteroids in the International Astronomical Union’s Minor Planet Centre, the largest database of Solar System objects. This left 1031 unidentified trails that are faint and likely to be smaller asteroids than those detected in ground-based surveys. The vast majority of these asteroids are expected to be located in the Main Belt between Mars and Jupiter, where asteroids of such small size are as yet poorly studied. These trails could give the astronomers insightful clues about the conditions in the early Solar System when the planets were forming.

The project highlights Hubble’s potential to image faint, previously unknown asteroids and represents a new approach to finding asteroids in astronomical archives spanning decades, which may be effectively applied to other datasets. In addition to illustrating Hubble’s value as an asteroid hunter, it also reinforced the public’s interest in contributing towards scientific endeavours and the value of citizen science efforts.

Next, the project will explore the 1031 streaks of previously unknown asteroids to characterise their orbits and study their properties, such as their sizes and rotation periods. As most of these asteroid streaks were captured by Hubble many years ago, it is not possible to follow them up now to determine their orbits. However, using Hubble, astronomers can use the parallax effect to determine the distance to the unknown asteroids and put constraints on their orbits. As Hubble moves around the Earth, it changes its point of view while observing the asteroid which also moves on its own orbit. By knowing the position of Hubble during the observation and measuring the curvature of the streaks, scientists can determine the distances to the asteroids and estimate the shapes of their orbits. Some of the longer Hubble observations facilitate the measurement of a light curve for the asteroids, from which the team can measure their rotation periods and infer their shapes.

Credits:

ESA/Hubble & NASA, S. Kruk (ESA/ESTEC), Hubble Asteroid Hunter citizen science team, M. Zamani (ESA/Hubble); CC BY 4.0

Nestled among the vast clouds of star-forming regions like this one lie potential clues about the formation of our own solar system.

This image from the NASA/ESA Hubble Space Telescope features AFGL 5180, a beautiful stellar nursery located in the constellation of Gemini (the Twins).

At the center of the image, a massive star is forming and blasting cavities through the clouds with a pair of powerful jets, extending to the top right and bottom left of the image. Light from this star is mostly escaping and reaching us by illuminating these cavities, like a lighthouse piercing through the storm clouds.

Stars are born in dusty environments and although this dust makes for spectacular images, it can prevent astronomers from seeing stars embedded in it. Hubble’s Wide Field Camera 3 (WFC3) instrument is designed to capture detailed images in both visible and infrared light, meaning that the young stars hidden in vast star-forming regions like AFGL 5180 can be seen much more clearly.

Credits: ESA/Hubble & NASA, J. C. Tan (Chalmers University & University of Virginia), R. Fedriani (Chalmers University); CC BY 4.0; Acknowledgment: Judy Schmidt

This image of the Moon was taken by ESA astronaut Alexander Gerst from the International Space Station during his Horizons mission. But he’s not the only one to be eyeing the Moon these days.

From 3 to 5 July, ESA is hosting a workshop on lunar exploration at its technical heart in the Netherlands. Building on ESA’s commitment to sustainable exploration, the workshop brings space experts and industry together to talk lunar resources and how to use them to return humanity to the Moon and farther afield.

For humans to live and work on the Moon and beyond, we need oxygen and water for life support as well as fuel and materials to build habitats and equipment. Launching these bulky consumables would cost the kind of money and energy that makes human exploration of the Solar System unsustainable.

Instead, ESA is looking into the capabilities that would allow humans to harness lunar resources for humanity’s sustainable return to the Moon. The approach is known as In-Situ Resource Utilisation. Put simply, it means extracting and processing resources on site to make useful products and services.

Last year, service providers with like-minded ideas were invited to take place in a one-year study exploring what a collaborative and commercially viable mission to the Moon would look like.

During this week’s workshop ESA is continuing this discussion with experts, industry officials, and potential new partners by exploring the technological readiness, commercial viability, legal status, and international context for lunar resource use.

In the meantime, the humans closest to our rocky satellite – astronauts on the International Space Station – are testing technologies such as remotely operating robots to take us a step closer to our next outpost in space.

Learn more about ESA’s vision for the next decade of space exploration here and dive into Alexander's Moon gazing during Horizon's mission in this blog post.

Credits: ESA/NASA

The twin galaxies NGC 4496A and NGC 4496B dominate the frame in this image from the NASA/ESA Hubble Space Telescope. Both galaxies lie in the constellation Virgo, but despite appearing side-by-side in this image they are at vastly different distances from both Earth and one another. NGC 4496A is 47 million light-years from Earth while NGC 4496B is 212 million light-years away. The enormous distances between the two galaxies mean that the two cannot interact, and they only appear to overlap owing to a chance alignment.

Chance galactic alignments such as this provide astronomers with the opportunity to delve into the distribution of dust in these galaxies. Galactic dust adds to the beauty of astronomical images — it can be seen in this image as the dark tendrils threading through both NGC 4496A and NGC 4496B — but it also complicates astronomers’ observations. Dust absorbs starlight, making stars seem dimmer and shifting their light towards longer wavelengths, a process that astronomers refer to as “reddening” (not the same thing as redshift). By carefully measuring how starlight from background galaxies is affected by dust in intervening galaxies, astronomers can map out where the dust is in the foreground galaxy’s spiral arms. The resulting “dust maps” help astronomers calibrate measurements of everything from cosmological distances to the types of stars populating galaxies.

Credits: ESA/Hubble & NASA, T. Boeker, B. Holwerda, Dark Energy Survey, DOE, FNAL/DECam, CTIO/NOIRLab/NSF/AURA, SDSS; CC BY 4.0

Acknowledgement: R. Colombari

Space Science image of the week:

In a fitting farewell to the planet that had been its home for over 13 years, the international Cassini spacecraft took one last, lingering look at Saturn and the splendid rings during the final leg of its journey and snapped a series of images that has been assembled into this new mosaic.

The mission concluded on 15 September with a planned dramatic plunge into the planet’s atmosphere. Two days earlier it captured wide-angle images to cover the planet and its main rings from one end to the other. The moons Prometheus, Pandora, Janus, Epimetheus, Mimas and Enceladus also make a faint appearance in the background. Can you spot them? (Click here for a labelled version of this image.)

The image shown here has been brightened to reveal the details of the moons and rings; the original natural colour view can be found here.

This view looks toward the sunlit side of the rings from about 15° above the ring plane. Cassini was 1.1 million km from Saturn, on its final approach to the planet, when the 42 red, green and blue images in this mosaic were taken. They were combined and mosaicked together to create a natural-colour view. The image scale on Saturn is about 67 km/ pixel. The image scale on the moons varies from 59 km/pixel to 80 km/pixel. The Sun-planet-spacecraft angle is 138°.

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

The image was first released on 20 November. Read the full story via the NASA website.

Credit: NASA/JPL-Caltech/Space Science Institute

This observation from the NASA/ESA Hubble Space Telescope showcases Arp 86, a peculiar pair of interacting galaxies which lies roughly 220 million light-years from Earth in the constellation Pegasus. Arp 86 is composed of the two galaxies NGC 7752 and NGC 7753 — NGC 7753 is the large spiral galaxy dominating this image, and NGC 7752 is its smaller companion. The diminutive companion galaxy almost appears to be attached to NGC 7753, and it is this peculiarity that has earned the designation “Arp 86” — signifying that the galaxy pair appears in the Atlas of Peculiar Galaxies compiled by the astronomer Halton Arp in 1966. The gravitational squabble between the two galaxies is doomed to end catastrophically for NGC 7752. It will eventually either be flung out into intergalactic space or be entirely engulfed by its far larger neighbour.

Hubble observed Arp 86 as part of a larger effort to understand the connections between young stars and the clouds of cold gas in which they form. Hubble gazed into star clusters and clouds of gas and dust in a variety of environments dotted throughout nearby galaxies. Combined with measurements from ALMA, a gigantic radio telescope perched high in the Chilean Andes, these Hubble observations provide a treasure trove of data for astronomers working to understand how stars are born.

These observations also helped sow the seeds of future research with an upcoming space telescope, the NASA/ESA James Webb Space Telescope (JWST). This telescope, due to launch later this year, will study star formation in dusty regions such as the galaxies of Arp 86.

Credits: ESA/Hubble and NASA, Dark Energy Survey, J. Dalcanton; CC BY 4.0

This image taken by the Colour and Stereo Surface Imaging System (CaSSIS) onboard the ExoMars Trace Gas Orbiter shows part of Alga Crater rim. The image was acquired on 28 January 2021.

Alga Crater is located in the southern highlands of Mars and is well-known for its colour diversity.

Bluer tones are more dust covered. The greenish colours are typically mafic minerals such as magnesium and/or iron-rich silicates, although spectroscopy is required to provide the most accurate identification.

The image is centred at 333.3ºE/24.5ºS. North is roughly to the left.

Read more about how CaSSIS reveals the colour diversity of Mars here

Credits: ESA/TGO/CaSSIS, CC BY-SA 3.0 IGO

The ultra-diffuse galaxy GAMA 526784 appears as a tenuous patch of light in this image from the NASA/ESA Hubble Space Telescope. This wispy object resides in the constellation Hydra, roughly four billion light-years from Earth. Ultra-diffuse galaxies such as GAMA 526784 have a number of peculiarities. For example, their dark matter content can be either extremely low or extremely high — ultra-diffuse galaxies have been observed with an almost complete lack of dark matter, whereas others consist of almost nothing but dark matter. Another oddity of this class of galaxies is their anomalous abundance of bright globular clusters, something not observed in other types of galaxies.

Hubble captured GAMA 526784 with the Advanced Camera for Surveys (ACS), which was installed in 2002 by astronauts during Hubble Servicing Mission 3B. Since then, the instrument has played a pivotal role in some of Hubble’s most impressive scientific results, including capturing the Hubble Ultra Deep Field. The ACS has also photographed Pluto in advance of the New Horizon mission, observed gargantuan gravitational lenses and found fully formed galaxies in the early Universe.

This image comes from a set of Hubble observations designed to shed light on the properties of ultra-diffuse galaxies. Hubble’s keen vision allowed astronomers to study GAMA 526784 in high resolution at ultraviolet wavelengths, helping to gauge the sizes and ages of the compact star-forming regions studding the galaxy.

Credits: ESA/Hubble & NASA, R. van der Burg; CC BY 4.0

Acknowledgement: L. Shatz