This luminous Picture of the Week shows Z 229-15 — imaged here in beautiful detail by the NASA/ESA Hubble Space Telescope — a celestial object that lies about 390 million light-years from Earth in the constellation Lyra. Z 229-15 is one of those interesting celestial objects that, should you choose to research it, you will find defined as several different things: sometimes as an active galactic nucleus (an AGN); sometimes as a quasar; and sometimes as a Seyfert galaxy. Which of these is Z 229-15 really? The answer is that it is all of these things all at once, because these three definitions have significant overlap.

AGNs and quasars are both described in detail in the Hubble Word Bank, but in essence an AGN is a small region at the heart of certain galaxies (called active galaxies) that is far brighter than just the galaxy’s stars would be. The extra luminosity is due to the presence of a supermassive black hole at the galaxy’s core. Material sucked into a black hole actually doesn’t fall directly into it, but instead is drawn into a swirling disc, from where it is inexorably tugged towards the black hole. This disc of matter gets so hot that it releases a large amount of energy across the electromagnetic spectrum, and that’s what makes AGNs appear so bright.

Quasars are a particular type of AGN; they are typically both extremely bright and extremely distant from Earth — several hundred million light-years is considered nearby for a quasar, making Z 229-15 positively local. Often an AGN is so bright that the rest of the galaxy cannot be seen, but Seyfert galaxies are active galaxies that host very bright AGNs (quasars) while the rest of the galaxy is still observable. So Z 229-15 is a Seyfert galaxy that contains a quasar, and that, by definition, hosts an AGN. Classification in astronomy can be a challenge!

[Image Description: A spiral galaxy. It has two almost-straight arms coming from the left and right of the core that meet a starry ring around the galaxy’s edge. The ring is bluish in colour, and the core is golden and shining. A faint halo of light also surrounds the galaxy. There is one bright star with many diffraction spikes, and a few small stars all around on a black background.]

Credits: ESA/Hubble & NASA, A. Barth, R. Mushotzky; CC BY 4.0

This image shows the spiral galaxy NGC 5037, which is found in the constellation of Virgo and was first documented by William Herschel in 1785. It lies about 150 million light-years away from Earth, and yet it is possible to see the delicate structures of gas and dust within the galaxy in extraordinary detail. This was made possible by Hubble’s Wide Field Camera 3 (WFC3), which was used to collect the exposures that were combined to create this image.

WFC3 is a very versatile camera, as it can collect ultraviolet, visible and infrared light, thereby providing a wealth of information about the objects that it observes. WFC3 was installed on Hubble by astronauts in 2009, during servicing mission 4, which was Hubble’s fifth and final servicing mission. Servicing mission 4 was intended to prolong Hubble’s life for another five years. 12 years later, both Hubble and WFC3 remain in active use!

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

Acknowledgement: L. Shatz

This Copernicus Sentinel-2 image highlights the colours of autumn over the southern part of New York state in the US.

The different shades of brown in the image, which is from November 2022, capture the colours of autumn. This is particularly evident in the upper part of the image where mountains and forests are typical of the region.

New York is one of the most populous states in the US. Here, we see the area surrounding the Hudson River in the top left, through New York City following the river southwards, to the Atlantic shores of Long Island, which dominates the centre of the image. Long Island lies almost parallel to the southern shore of Connecticut, separated by Long Island Sound, a 145-km-long inlet of the North Atlantic Ocean.

The lighter tones of blue in the waters of Long Island Sound and Great South Bay – the lagoon on the southern shore of the island – show sediment shaped like eddies owing to surface currents.

Visible as a grey area to the west of Long Island is New York City. It comprises five boroughs, with the island of Manhattan in the centre bound by the Hudson, East and Harlem rivers. The meeting of the Hudson and East Rivers has formed one of the world’s largest natural harbours.

Separated from New York by the Hudson River, part of New Jersey is also visible in the bottom left of the image.

Zooming in, a number of iconic places can be spotted, including the 340-hectare green rectangle of Central Park at the centre of Manhattan Island, the Brooklyn Bridge, one of the three connecting Brooklyn and Manhattan, and Liberty Island, with the famous Statue of Liberty, which is off the southern tip of Manhattan.

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

Image of a sunset or sunrise seen from the International Space Station. ESA astronaut Matthias Maurer captured and posted this image to his social channels on 23 January 2022 with the caption:

He posted this to his social channels on 20 January 2022 with the caption: "The beauty of a sunset / sunrise. This thin layer of atmosphere is what makes our planet unique and provides the basis for all life. From space it seems more fragile, prone, unguarded and vulnerable than the scent of perfume."

Visit the Cosmic Kiss mission page to learn more about Matthias’s mission.

Credits: ESA/NASA; CC BY-NC-SA 2.0

A vast galaxy cluster lurks in the centre of this image from the NASA/ESA Hubble Space Telescope. Like a submerged sea monster causing waves on the surface, this cosmic leviathan can be identified by the distortions in spacetime around it. The mass of the cluster has caused the images of background galaxies to be gravitationally lensed; the galaxy cluster has caused a sufficient curvature of spacetime to bend the path of light and cause background galaxies to appear distorted into streaks and arcs of light. A host of other galaxies can be seen surrounding the cluster, and a handful of foreground stars with tell-tale diffraction spikes are scattered throughout the image.

This particular galaxy cluster is called eMACS J1823.1+7822, and lies almost nine billion light-years away in the constellation Draco. It is one of five exceptionally massive galaxy clusters explored by Hubble in the hopes of measuring the strengths of these gravitational lenses and providing insights into the distribution of dark matter in galaxy clusters. Strong gravitational lenses like eMACS J1823.1+7822 can help astronomers study distant galaxies by acting as vast natural telescopes which magnify objects that would otherwise be too faint or distant to resolve.

This multiwavelength image layers data from eight different filters and two different instruments: Hubble’s Advanced Camera for Surveys and Wide Field Camera 3. Both instruments have the ability to view astronomical objects in just a small slice of the electromagnetic spectrum using filters, which allow astronomers to image objects at precisely selected wavelengths. The combination of observations at different wavelengths lets astronomers develop a more complete picture of the structure, composition and behaviour of an object than visible light alone would reveal.

[Image description: A cluster of large galaxies, surrounded by various stars and smaller galaxies on a dark background. The central cluster is mostly made of bright elliptical galaxies that are surrounded by a warm glow. Close to the cluster core is the stretched, distorted arc of a galaxy, gravitationally lensed by the cluster.]

Credits: ESA/Hubble & NASA, H. Ebeling; CC BY 4.0

Hubble’s 2021 image of Jupiter tracks 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, where 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. While 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 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.

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

What looks much like craggy mountains on a moonlit evening is actually the edge of a nearby, young, star-forming region NGC 3324 in the Carina Nebula. Captured in infrared light by the Near-Infrared Camera (NIRCam) on the NASA/ESA/CSA James Webb Space Telescope, this image reveals previously obscured areas of star birth.

Called the Cosmic Cliffs, the region is actually the edge of a gigantic, gaseous cavity within NGC 3324, roughly 7,600 light-years away. The cavernous area has been carved from the nebula by the intense ultraviolet radiation and stellar winds from extremely massive, hot, young stars located in the centre of the bubble, above the area shown in this image. The high-energy radiation from these stars is sculpting the nebula’s wall by slowly eroding it away.

NIRCam – with its crisp resolution and unparalleled sensitivity – unveils hundreds of previously hidden stars, and even numerous background galaxies. Several prominent features in this image are described below.

- The “steam” that appears to rise from the celestial “mountains” is actually hot, ionised gas and hot dust streaming away from the nebula due to intense, ultraviolet radiation.

- Dramatic pillars rise above the glowing wall of gas, resisting the blistering ultraviolet radiation from the young stars.

- Bubbles and cavities are being blown by the intense radiation and stellar winds of newborn stars.

- Protostellar jets and outflows, which appear in gold, shoot from dust-enshrouded, nascent stars.

- A “blow-out” erupts at the top-centre of the ridge, spewing gas and dust into the interstellar medium.

- An unusual “arch” appears, looking like a bent-over cylinder.

This period of very early star formation is difficult to capture because, for an individual star, it lasts only about 50,000 to 100,000 years – but Webb’s extreme sensitivity and exquisite spatial resolution have chronicled this rare event.

Located roughly 7,600 light-years away, NGC 3324 was first catalogued by James Dunlop in 1826. Visible from the Southern Hemisphere, it is located at the northwest corner of the Carina Nebula (NGC 3372), which resides in the constellation Carina. The Carina Nebula is home to the Keyhole Nebula and the active, unstable supergiant star called Eta Carinae.

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

Get the full array of Webb’s first images and spectra, including downloadable files, here.

Credits: NASA, ESA, CSA, STScI

School is also back in session for ESA astronaut Andrea Mogensen (right) and NASA astronaut Kathleen Rubins. Together with European Astronaut Centre engineer Robin Eccleston (far left), the trio are taking part in this year’s Pangaea field training campaign to become better field scientists.

With all eyes set on the Moon, the three-week campaign has increasingly focussed on lunar geology. Now in its fourth edition, the course kicked off this week with background lessons by top planetary scientists on identifying rock samples of interest for exploration.

In this image Andreas and his fellow students use a microscope to analyse samples.

Later, the class went on a field trip to the Bletterbach canyon in the Italian Dolomites. The eight-km long and 400-m deep gorge contains around 10 billion tonnes of rock transported to the valley since the end of the glacial age, around 18 000 years ago.

The gorge is the result of sedimentary processes quite similar to those found on Mars and is an ideal site to put classroom knowledge into practice.

In later sessions, the trainees will also visit the Ries Crater in Germany and the volcanic landscapes of Lanzarote, Spain, to unravel not only lunar but also martian features on Earth. They will use more sophisticated tools that will allow them to explore their geography from the microscopic to the macroscopic level.

The participants will wear a virtual reality headset to immerse themselves in a real martian landscape. Together with images and dozens of 3D maps, the trainees will see a combination of ground truth information and satellite images with the PLANetary MAPping project (PLANMAP) running behind the scenes.

Follow Pangaea on social media for live updates and on the blog for more in depth articles.

Credits: ESA–A. Romeo

A bright young star is surrounded by a shroud of thick gas and dust in this image from the NASA/ESA Hubble Space Telescope. Hubble’s Wide Field Camera 3 inspected a young stellar object, over 9000 light years away in the constellation Taurus, to help astronomers understand the earliest stages in the lives of massive stars. This object — which is known to astronomers as IRAS 05506+2414 — is thought to be an example of an explosive event caused by the disruption of a massive young star system. If so, it would only be the second such example known.

Usually the swirling discs of material surrounding a young star are funnelled into twin outflows of gas and dust from the star. In the case of IRAS 05506+2414, however, a fan-like spray of material travelling at velocities of up to 350 kilometres per second is spreading outwards from the centre of this image.

Astronomers turned to Hubble’s Wide Field Camera 3 to measure the distance to IRAS 05506+2414. While it is possible to measure the velocity of material speeding outwards from the star, astronomers cannot tell how far from Earth the star actually is from a single observation. However, by measuring the distance that the outflow travels between successive images, they will be able to infer the distance to IRAS 05506+2414. This will allow astronomers to determine how bright the star is and how much energy it is emitting, and hence to estimate its mass — all vital information that will help to understand the origin of this bright young star’s unusual outflow.

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

This image from the NASA/ESA/CSA James Webb Space Telescope depicts IC 1623, an entwined pair of interacting galaxies which lies around 270 million light-years from Earth in the constellation Cetus. The two galaxies in IC 1623 are plunging headlong into one another in a process known as a galaxy merger. Their collision has ignited a frenzied spate of star formation known as a starburst, creating new stars at a rate more than twenty times that of the Milky Way galaxy.

This interacting galaxy system is particularly bright at infrared wavelengths, making it a perfect proving ground for Webb’s ability to study luminous galaxies. A team of astronomers captured IC 1623 across the infrared portions of the electromagnetic spectrum using a trio of Webb’s cutting-edge scientific instruments: MIRI, NIRSpec, and NIRCam. In so doing, they provided an abundance of data that will allow the astronomical community at large to fully explore how Webb’s unprecedented capabilities will help to unravel the complex interactions in galactic ecosystems. These observations are also accompanied by data from other observatories, including the NASA/ESA Hubble Space Telescope, and will help set the stage for future observations of galactic systems with Webb.

The merger of these two galaxies has long been of interest to astronomers, and has previously been imaged by Hubble and by other space telescopes. The ongoing, extreme starburst causes intense infrared emission, and the merging galaxies may well be in the process of forming a supermassive black hole. A thick band of dust has blocked these valuable insights from the view of telescopes like Hubble. However, Webb’s infrared sensitivity and its impressive resolution at those wavelengths allows it to see past the dust and has resulted in the spectacular image above, a combination of MIRI and NIRCam imagery.

The luminous core of the galaxy merger turns out to be both very bright and highly compact, so much so that Webb’s diffraction spikes appear atop the galaxy in this image. The 8-pronged, snowflake-like diffraction spikes are created by the interaction of starlight with the physical structure of the telescope. The spiky quality of Webb’s observations is particularly noticeable in images containing bright stars, such as Webb’s first deep field image.

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.

NIRSpec was built for the European Space Agency (ESA) by a consortium of European companies led by Airbus Defence and Space (ADS) with NASA’s Goddard Space Flight Center providing its detector and micro-shutter subsystems.

Credits: ESA/Webb, NASA & CSA, L. Armus & A. Evans; CC BY 4.0

Acknowledgement: R. Colombari

This image was taken on 22 March 2021 in the Lunae Planum region [16.74°N, 300.9°E] of Mars by the CaSSIS camera on the ESA-Roscosmos ExoMars Trace Gas Orbiter (TGO).

This region is known to be covered by large lava deposits probably from the nearby Tharsis Montes volcanoes. In this image three medium-sized impact craters take centre stage, with many smaller impacts pockmarking the scene. Zooming into the larger craters it is possible to see layers in the inner rim that could represent the successive accumulation of lava flows in this area.

TGO’s full science mission began in 2018. The spacecraft is not only returning spectacular images, but also providing the best ever inventory of the planet’s atmospheric gases, and mapping the planet’s surface for water-rich locations. It will also provide data relay services for the second ExoMars mission comprising the Rosalind Franklin rover and Kazachok platform, when it arrives on Mars in 2023.

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

A volcano on the Italian island of Stromboli erupted early on Sunday morning, releasing huge plumes of smoke and a lava flow pouring into the sea. The Copernicus Sentinel-2 mission captured this image of the aftermath less than five hours after the eruption.

The eruption caused the partial collapse of the crater terrace which was followed by major flows of lava stretching to the sea and enormous plumes of smoke rising several hundred metres above the volcano. Italian civil protection authorities raised the alert from yellow to orange as the ‘situation of enhanced volcano imbalance persists.’

This Sentinel-2 image has been processed in true colour, using the shortwave infrared channel to highlight the new flow of lava. 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 northernmost island of the Aeolian archipelago, located just off the northern tip of Sicily, Stromboli’s volcano has been erupting almost continuously for the past 90 years.

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

This image from the NASA/ESA Hubble Space Telescope features the galaxy LEDA 48062 in the constellation Perseus. LEDA 48062 is the faint, sparse, amorphous galaxy on the right side of this image, and it is accompanied by a more sharply defined neighbour on the left, the large, disc-like lenticular galaxy UGC 8603. A smattering of more distant galaxies also litter the background, and a handful of foreground stars are also visible throughout the image.

Have you ever wondered why the stars in Hubble images are surrounded by four sharp points? These are called diffraction spikes, and are created when starlight diffracts — or spreads around — the support structures inside reflecting telescopes like Hubble. The four spikes are due to the four thin vanes supporting Hubble’s secondary mirror and are only noticeable for bright objects like stars where a lot of light is concentrated on one spot. Darker, more spread-out objects like the galaxies LEDA 48062 and UGC 8603 do not possess visible diffraction spikes.

Hubble recently spent some time with our galactic neighbours. LEDA 48062 is only around 30 million light-years from the Milky Way, and was therefore included in the observing campaign Every Known Nearby Galaxy. The aim of this campaign was to observe precisely that: every known galaxy within 10 megaparsecs (around 33 million light-years) of the Milky Way. By getting to know our galactic neighbours, astronomers can determine what types of stars reside in various galaxies and also map out the local structure of the Universe.

[Image description: A faint, scattered collection of cool stars in the form of an irregular galaxy lies right of centre. A disc-shaped galaxy viewed nearly edge-on lies to the left, surrounded by a wide glow. Several smaller galaxies in various orientations cluster around the two. The background is black and mostly empty.]

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

The stately sweeping spiral arms of the spiral galaxy NGC 5495 are revealed by the NASA/ESA Hubble Space Telescope’s Wide Field Camera 3 in this image. NGC 5495, which lies around 300 million light-years from Earth in the constellation Hydra, is a Seyfert galaxy, a type of galaxy with a particularly bright central region. These luminous cores — known to astronomers as active galactic nuclei — are dominated by the light emitted by dust and gas falling into a supermassive black hole.

This image is drawn from a series of observations captured by astronomers studying supermassive black holes lurking in the hearts of other galaxies. Studying the central regions of galaxies can be challenging: as well as the light created by matter falling into supermassive black holes, areas of star formation and the light from existing stars all contribute to the brightness of galactic cores. Hubble’s crystal-clear vision helped astronomers disentangle the various sources of light at the core of NGC 5495, allowing them to precisely weigh its supermassive black hole.

As well as NGC 5495, two stellar interlopers are visible in this image. One is just outside the centre of NGC 5495, and the other is very prominent alongside the galaxy. While they share the same location on the sky, these objects are much closer to home than NGC 5495: they are stars from our own Milky Way. The bright stars are surrounded by criss-cross diffraction spikes, optical artefacts created by the internal structure of Hubble interacting with starlight.

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

Acknowledgement: R. Colombari

The galaxy NGC 6946 is nothing short of spectacular. In the last century alone, NGC 6946 has experienced 10 observed supernovae, earning its nickname as the Fireworks Galaxy. In comparison, our Milky Way averages just 1-2 supernova events per century. This NASA/ESA Hubble Space Telescope image shows the stars, spiral arms, and various stellar environments of NGC 6946 in phenomenal detail.

We are able to marvel at NGC 6946 as it is a face-on galaxy, which means that we see the galaxy “facing” us, rather than seeing it from the side (known as edge-on). The Fireworks Galaxy is further classified as an intermediate spiral galaxy and as a starburst galaxy. The former means the structure of NGC 6946 sits between a full spiral and a barred spiral galaxy, with only a slight bar in its centre, and the latter means it has an exceptionally high rate of star formation.

The galaxy resides 25.2 million light-years away, along the border of the northern constellations of Cepheus and Cygnus (The Swan).

Credits: ESA/Hubble & NASA, A. Leroy, K. S. Long; CC BY 4.0

First image of the full Earth disc from the Meteosat Third Generation Imager. The first image from Meteosat Third Generation – Imager 1 (MTG-I1) reveals a level of detail about the weather over Europe and Africa not previously possible from 36 000 km above Earth. The higher-resolution images provided by the instruments on board give weather forecasters more information about the clouds cloaking much of Europe and visible in the equatorial region of Africa and the Atlantic Ocean. Sand and sediment in the waters off Italy are also visible, as well as dust or smog being carried from south Asia. This degree of detail is not possible from the instruments on the Meteosat Second Generation satellites. The image was captured at 11:50 UTC on 18 March 2023 by the Flexible Combined Imager on MTG-I1.

Read full story

Credits: EUMETSAT/ESA

A small, dense cloud of gas and dust called CB 130-3 blots out the centre of this image from the NASA/ESA Hubble Space Telescope. CB 130-3 is an object known as a dense core, a compact agglomeration of gas and dust. This particular dense core is in the constellation Serpens, and seems to billow across a field of background stars.

Dense cores like CB 130-3 are the birthplaces of stars, and as such are of particular interest to astronomers. During the collapse of these cores enough mass can accumulate in one place to reach the temperatures and densities required to ignite hydrogen fusion, marking the birth of a new star. While it may not be obvious from this image, a compact object teetering on the brink of becoming a fully fledged star is embedded deep within CB 130-3.

Astronomers used Hubble’s Wide Field Camera 3 to better understand the environment surrounding this fledgling star. As this image shows, the density of CB 130-3 isn’t constant; the outer edges of the cloud consist of only tenuous wisps, whereas at its core CB 130-3 blots out background light entirely. The gas and dust making up CB 130-3 affect not only the brightness but also the colour of background stars, with stars towards the centre the cloud appearing redder than their counterparts at the outskirts of this image. Astronomers used Hubble to measure this reddening effect and chart out the density of CB 130-3, providing insights into the inner structure of this stellar nursery.

Credits: ESA/Hubble, NASA & STScI, C. Britt, T. Huard, A. Pagan; CC BY 4.0

This spectacular image from the NASA/ESA Hubble Space Telescope shows the trailing arms of NGC 2276, a spiral galaxy 120 million light-years away in the constellation of Cepheus. At first glance, the delicate tracery of bright spiral arms and dark dust lanes resembles countless other spiral galaxies. A closer look reveals a strangely lopsided galaxy shaped by gravitational interaction and intense star formation.

This striking image showcases the unusually contorted appearance of NGC 2276, an appearance caused by two different astrophysical interactions — one with the superheated gas pervading galaxy clusters, and one with a nearby galactic neighbour.

The interaction of NGC 2276 with the intracluster medium — the superheated gas lying between the galaxies in galaxy clusters — has ignited a burst of star formation along one edge of the galaxy. This wave of star formation is visible as the bright, blue-tinged glow of newly formed massive stars towards the left side of this image, and gives the galaxy a strangely lopsided appearance. NGC 2276’s recent burst of star formation is also related to the appearance of more exotic inhabitants — black holes and neutron stars in binary systems.

On the other side of the galaxy from this burst of new stars, the gravitational attraction of a smaller companion is pulling the outer edges of NGC 2276 out of shape. This interaction with the small lens-shaped galaxy NGC 2300 has distorted the outermost spiral arms of NGC 2276, giving the false impression that the larger galaxy is orientated face-on to Earth. NGC 2276 and its disruptive companion NGC 2300 can both be seen in the accompanying image, which shows a wider view of the interacting galaxies.

NGC 2276 is by no means the only galaxy with a strange appearance. The Atlas of Peculiar Galaxies — a catalogue of unusual galaxies published in 1966 — contains a menagerie of weird and wonderful galaxies, including spectacular galaxy mergers, ring-shaped galaxies, and other galactic oddities. As befits an unusually contorted galaxy, NGC 2276 has the distinction of being listed in the Atlas of Peculiar Galaxies twice — once for its lopsided spiral arms and once for its interaction with its smaller neighbour NGC 2300.

Credits: ESA/Hubble & NASA, P. Sell; CC BY 4.0

Acknowledgement: L. Shatz

The James Webb Space Telescope was fuelled inside the payload preparation facility at Europe’s Spaceport in French Guiana ahead of its launch on Ariane 5.

Webb’s thrusters will use this propellant to make critical course-corrections after separation from Ariane 5, to maintain its prescribed orbit about one and a half million kilometres from Earth, and to repoint the observatory and manage its momentum during operations.

Fuelling any satellite is a particularly delicate operation requiring setup of the equipment and connections, fuelling, and then pressurisation.

Webb’s propellant tanks were filled separately with 133 kg of dinitrogen tetroxide oxidiser and 168 kg hydrazine. Oxidiser improves the burn efficiency of the hydrazine fuel.

These propellants are extremely toxic so only a few specialists wearing Self-Contained Atmospheric Protective Ensemble, or ‘scape’ suits, remained in the dedicated fuelling hall for fuelling which took 10 days and ended on 3 December.

The next steps will start soon for ‘combined operations’. This is when specialists working separately to prepare Webb and Ariane 5 will come together as one team. They will place Webb atop its Ariane 5 launch vehicle and encapsulate it inside Ariane 5’s fairing.

Then, no longer visible, Webb, joined with its Ariane 5 launch vehicle will be transferred to the Final Assembly building for the final preparations before launch.

Webb will be the largest, most powerful telescope ever launched into space. As part of an international collaboration agreement, ESA is providing 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.

Webb is an international partnership between NASA, ESA and the Canadian Space Agency (CSA).

Find out more about Webb in ESA’s launch kit and interactive brochure.

Credits: ESA/CNES/Arianespace/Optique Vidéo du CSG - P Piron

This packed ESA/Hubble Picture of the Week showcases the galaxy cluster ACO S 295, as well as a jostling crowd of background galaxies and foreground stars. Galaxies of all shapes and sizes populate this image, ranging from stately spirals to fuzzy ellipticals. As well as a range of sizes, this galactic menagerie boasts a range of orientations, with spiral galaxies such as the one at the centre of this image appearing almost face on, and some edge-on spiral galaxies visible only as thin slivers of light.

The cluster dominates the centre of this image, both visually and physically. The huge mass of the galaxy cluster has gravitationally lensed the background galaxies, distorting and smearing their shapes. As well as providing astronomers with a natural magnifying glass with which to study distant galaxies, gravitational lensing has subtly framed the centre of this image, producing a visually striking scene.

Credits: ESA/Hubble & NASA, F. Pacaud, D. Coe; CC BY 4.0

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

The lonely spiral galaxy UGC 9391 is shown in this image from the NASA/ESA Hubble Space Telescope’s Wide Field Camera 3. This spiral galaxy resides 130 million light years from Earth in the constellation Draco near the North celestial pole. The star-studded spiral arms stand in splendid isolation against a backdrop of distant galaxies, which are only visible as indistinct swirls or smudges thanks to their vast distances from Earth. The image also features some much brighter foreground stars from closer to home. These bright nearby stars are ringed with diffraction spikes — prominent spikes caused by light interacting with the inner workings of Hubble’s complicated optics. Hubble’s most striking astronomical images often include these three different layers — a field of distant galaxies, the object that Hubble is observing, and a handful of bright interloping stars from the Milky Way.

This image is from a set of observations in which astronomers used Hubble to construct the “Cosmic Distance Ladder” — a set of connected measurements allowing the distances to the furthest astronomical objects to be determined. Astronomical distances are only directly measurable for relatively nearby objects — closer than 3000 light years or so. For distances beyond this, astronomers rely on a set of measured correlations calibrated against nearby objects. UGC 9391 helped astronomers improve their distance estimates by providing a natural laboratory to compare two measuring techniques — supernova explosions and Cepheid variables. Improving the precision of distance measurements helps astronomers quantify how quickly the Universe is expanding — one of Hubble’s key science goals.

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

This spectacular image feature the spiral galaxy IC 5332, taken by the NASA/ESA Hubble Space Telescope.

The image shows dark regions that seem to separate the spiral arms, whereas the Webb image shows more of a continual tangle of structures that echo the spiral arms’ shape. This difference is due to the presence of dusty regions in the galaxy. Ultraviolet and visible light are far more prone to being scattered by interstellar dust than infrared light. Therefore dusty regions can be identified easily in the Hubble image as the darker regions that much of the galaxy’s ultraviolet and visible light has not been able to travel through. Those same dusty regions are no longer dark in the Webb image, however, as the mid-infrared light from the galaxy has been able to pass through them. Different stars are visible in the two images, which can be explained because certain stars shine brighter in the ultraviolet, visible and infrared regimes respectively. The images complement one another in a remarkable way, each telling us more about IC 5332’s structure and composition.

Credits: ESA/Webb, NASA & CSA, J. Lee and the PHANGS-JWST and PHANGS-HST Teams; CC BY 4.0

This star-studded image from the NASA/ESA Hubble Space Telescope shows the heart of the globular cluster NGC 6638 in the constellation Sagittarius. The star-strewn observation highlights the density of stars at the heart of globular clusters, which are stable, tightly bound clusters of tens of thousands to millions of stars. To capture the data in this image, Hubble used two of its cutting-edge astronomical instruments: Wide Field Camera 3 and the Advanced Camera for Surveys.

Hubble revolutionised the study of globular clusters, as it is almost impossible to clearly distinguish the stars in globular clusters with ground-based telescopes. The blurring caused by Earth’s atmosphere makes it impossible to tell one star from another, but from Hubble’s location in low Earth orbit the atmosphere no longer poses a problem. As a result, Hubble has been used to study what kind of stars globular clusters are made up of, how they evolve, and the role of gravity in these dense systems.

The NASA/ESA/CSA James Webb Space Telescope will further our understanding of globular clusters by peering into those globular clusters that are currently obscured by dust. Webb will predominantly observe at infrared wavelengths, which are less affected by the gas and dust surrounding newborn stars. This will allow astronomers to inspect star clusters that are freshly formed, providing insights into stellar populations before they have a chance to evolve.

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

A host of astronomical objects throng this image from the NASA/ESA Hubble Space Telescope. Background galaxies ranging from stately spirals to fuzzy ellipticals are strewn across the image, and bright foreground stars much closer to home are also present, surrounded by diffraction spikes. In the centre of the image, the vague shape of the small galaxy UGC 7983 appears as a hazy cloud of light. UGC 7983 is around 30 million light-years from Earth in the constellation Virgo, and is a dwarf irregular galaxy — a type thought to be similar to the very earliest galaxies in the Universe.

This image also conceals an astronomical interloper. A minor asteroid, only a handful of kilometres across, can be seen streaking across the upper left-hand side of this image. The trail of the asteroid is visible as four streaks of light separated by small gaps. These streaks of light represent the four separate exposures that were combined to create this image, the small gaps between each observation being necessary to change the filters inside Hubble’s Advanced Camera for Surveys.

Capturing an asteroid was a fortunate side effect of a larger effort to observe every known galaxy close to the Milky Way. When this project was first proposed, roughly 75% of all the Milky Way’s near galactic neighbours had been imaged by Hubble. A group of astronomers proposed using the gaps between longer Hubble observations to capture images of the remaining 25%. The project was an elegantly efficient way to fill out some gaps not only in Hubble's observing schedule, but also in our knowledge of nearby galaxies.

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

This Picture of the Week revisits the Veil Nebula, a popular subject for Hubble images! This object was featured in a previous Hubble photo release, but now new processing techniques have been applied, bringing out fine details of the nebula’s delicate threads and filaments of ionised gas.

To create this colourful image, observations taken by Hubble's Wide Field Camera 3 instrument through 5 different filters were used. The new post-processing methods have further enhanced details of emissions from doubly ionised oxygen (seen here in blues), ionised hydrogen and ionised nitrogen (seen here in reds).

The Veil Nebula lies around 2100 light-years from Earth in the constellation of Cygnus (The Swan), making it a relatively close neighbour in astronomical terms. Only a small portion of the nebula was captured in this image.

The Veil Nebula is the visible portion of the nearby Cygnus Loop, a supernova remnant formed roughly 10 000 years ago by the death of a massive star. The Veil Nebula’s progenitor star — which was 20 times the mass of the Sun — lived fast and died young, ending its life in a cataclysmic release of energy. Despite this stellar violence, the shockwaves and debris from the supernova sculpted the Veil Nebula’s delicate tracery of ionised gas — creating a scene of surprising astronomical beauty.

Credits: ESA/Hubble & NASA, Z. Levay; CC BY 4.0

The subject of this image is a group of three galaxies, collectively known as NGC 7764A. They were imaged by the NASA/ESA Hubble Space Telescope, using both its Advanced Camera for Surveys (ACS) and Wide Field Camera 3 (WFC3). The two galaxies in the upper right of the image appear to be interacting with one another — indeed, the long trails of stars and gas extending from them both give the impression that they have both just been struck at great speed, thrown into disarray by the bowling-ball-shaped galaxy to the lower left of the image. In reality, however, interactions between galaxies happen over very long time periods, and galaxies rarely collide head-on with one another. It is also unclear whether the galaxy to the lower left is actually interacting with the other two, although they are so relatively close in space that it seems possible that they are. By happy coincidence, the collective interaction between these galaxies have caused the two on the upper right to form a shape, which from our Solar System's perspective, ressembles the starship known as the USS Enterprise from Star Trek!

NGC 7764A, which lies about 425 million light years from Earth in the constellation Phoenix, is a fascinating example of just how awkward astronomical nomenclature can be. The three galaxies are individually referred to as NGC 7764A1, NGC 7764A2 and NGC 7764A3, and just to be really difficult, an entirely separate galaxy, named NGC 7764, sits in the skies about a Moon’s distance (as seen from Earth) away. This rather haphazard naming makes more sense when we consider that many of the catalogues for keeping track of celestial bodies were compiled well over 100 years ago, long before modern technology made standardising scientific terminology much easier. As it is, many astronomical objects have several different names, or might have names that are so similar to other objects’ names that they cause confusion.

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

Acknowledgement: J. Schmidt

The Copernicus Sentinel-3 mission captured this impressive shot of the almost cloud-free Scandinavian Peninsula on 20 March 2022.

The Scandinavian Peninsula, which comprises Sweden and Norway, is approximately 1850 km long. It extends southward from the Barents Sea in the north, the Norwegian sea to the west and the Gulf of Bothnia and the Baltic Sea to the east. Denmark, Finland, Latvia and Lithuania are also visible in this week’s image.

Along the left side of the peninsula, the jagged fjords lining Norway’s coast can be spotted from space. Many of these fjords were carved out by the thick glaciers that formed during the last ice age. The largest and deepest fjord on Norway’s coast, called Sognefjord, lies in southwest Norway and is 1308 m deep.

Sweden’s topography consists mainly of flat, rolling lowlands dotted with lakes. Lake Vänern and Lake Vättern, the largest lakes of Sweden, are clearly visible at the bottom of the peninsula. The lakes do not freeze completely during the winter months. To the northeast of the peninsula lies Finland with more than 55 000 lakes – most of which were also created by glacial deposits.

During March, much of northern Europe and Scandinavia had been affected by a strong high-pressure weather system, which also allowed for this almost cloud-free acquisition. On 19 March in Tirstrup, Denmark, the atmospheric pressure reached 1051.6 hPa, the highest value ever recorded in March.

Carrying a suite of cutting-edge instruments, Copernicus Sentinel-3 measures Earth’s oceans, land, ice and atmosphere to monitor and understand large-scale global dynamics. It provides essential information in near-real time for ocean and weather forecasting.

With a focus towards our oceans, Sentinel-3 measures the temperature, colour and height of the sea surface as well as the thickness of sea ice, while, over land, the mission maps the way land is used, provides indices of vegetation state and measures the height of rivers and lakes.

A technical note: the image is a mosaic of 2 descending orbits with a difference of around 60 minutes between them, hence the observable striping at the top of the image.

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

The 12-member crew of Concordia research station woke up to a most welcome sight in early August: sunrise, after four months of Antarctic darkness.

The return of the sun is a major milestone for the isolated and confined crew; they are three-quarters of the way through their Antarctic residency and will soon prepare to welcome the summer influx of researchers at the base.

ESA-sponsored medical doctor Hannes Hagson snapped this picture from the Station’s front door in early on 5 August. “Time here has the strange quality of both passing really quickly and very slowly at the same time,” he shared, “and in just two days we expect the return of the sun to grace us here at 75 degrees south! The returning daylight certainly has us all cheered up and starting to sense the beginning of the final part of this adventure.”

The winter months in Antarctica are tough, with temperatures dropping below −80C under a pitch black sky.

To combat winter blues, the crew keep busy, celebrating mid-winter (and the half-way point in their Antarctic stay) in June with their own traditions and taking part in the Antarctic Winter Games in July. Stations with a winter crew across Antarctica participate in a series of physical challenges and friendly competition.

With August comes not only sunlight, but production work for the Antarctic Film Festival, with each base submitting an original piece. Check out last year’s winning entry from Concordia in the Open category.

Of course, it’s not all fun and games. Hannes has been busy with biomedical research, as he continues to gather data from crew urine, stool and blood samples, as well as cognitive and psychological measures through questionnaires to study the effects of isolated, confined and extreme environments on the human body.

In October the crew will begin to prepare the base for the summer campaign. Rooms and tents must be prepared for the 40 or so incoming researchers.

Follow Hannes along on this adventure on the Concordia blog.

Credits: ESA/IPEV/PNRA–H. Hagson

The Full Sun Imager of the Extreme Ultraviolet Imager on board the ESA/NASA Solar Orbiter spacecraft captured a giant solar eruption on 15 February 2022.

Solar prominences are large structures made of tangled magnetic field lines that keep dense concentrations of solar plasma suspended above the Sun’s surface and often take the form of arching loops.

This is the largest solar prominence eruption ever observed in a single image together with the full solar disc.

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Credits: Solar Orbiter/EUI Team/ESA & NASA

The NASA/ESA/CSA James Webb Space Telescope has captured a high-resolution image of a tightly bound pair of actively forming stars, known as Herbig-Haro 46/47, in near-infrared light. Look for them at the centre of the red diffraction spikes. The stars are buried deeply, appearing as an orange-white splotch. They are surrounded by a disc of gas and dust that continues to add to their mass.

Herbig-Haro 46/47 is an important object to study because it is relatively young — only a few thousand years old. Stars take millions of years to form. Targets like this also give researchers insight into how stars gather mass over time, potentially allowing them to model how our own Sun, a low-mass star, formed.

The two-sided orange lobes were created by earlier ejections from these stars. The stars’ more recent ejections appear as blue, thread-like features, running along the angled diffraction spike that covers the orange lobes.

Actively forming stars ingest the gas and dust that immediately surrounds them in a disc (imagine an edge-on circle encasing them). When the stars ‘eat’ too much material in too short a time, they respond by sending out two-sided jets along the opposite axis, settling down the star’s spin, and removing mass from the area. Over millennia, these ejections regulate how much mass the stars retain.

Don’t miss the delicate, semi-transparent blue cloud. This is a region of dense dust and gas, known as a nebula. Webb’s crisp near-infrared image lets us see through its gauzy layers, showing off a lot more of Herbig-Haro 46/47, while also revealing a wide range of stars and galaxies that lie far beyond it. The nebula’s edges transform into a soft orange outline, like a backward L along the right and bottom of the image.

The blue nebula influences the shapes of the orange jets shot out by the central stars. As ejected material rams into the nebula on the lower left, it takes on wider shapes, because there is more opportunity for the jets to interact with molecules within the nebula. Its material also causes the stars’ ejections to light up.

Over millions of years the stars in Herbig-Haro 46/47 will form fully — clearing the scene.

Take a moment to linger on the background. A profusion of extremely distant galaxies dot Webb’s view. Its composite NIRCam (Near-Infrared Camera) image is made up of several exposures, highlighting distant galaxies and stars. Blue objects with diffraction spikes are stars, and the closer they are, the larger they appear. White-and-pink spiral galaxies sometimes appear larger than these stars, but are significantly farther away. The tiniest red dots, Webb’s infrared specialty, are often the oldest, most distant galaxies.

[Image description: At the centre is a thin horizontal orange cloud tilted from bottom left to top right. It takes up about two-thirds of the length of this angle, but is thin at the opposite angle. At its centre is a set of very large red and pink diffraction spikes in Webb’s familiar eight-pointed pattern. It has a central yellow-white blob, which hides two tightly orbiting stars. The background is filled with stars and galaxies.]

Credits: NASA, ESA, CSA, J. DePasquale (STScI)

This image from ESA’s Mars Express shows the complex cratered region of Terra Sirenum, southwest of Pickering Crater. Click here for annotated version.

This image comprises data gathered by Mars Express’ High Resolution Stereo Camera (HRSC) on 5 April 2022. 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. It is a ‘true colour’ image, reflecting what would be seen by the human eye if looking at this region of Mars.

The ground resolution is approximately 15 m/pixel and the image is centred at about 232°E/38°S. North is to the right.

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

The barred spiral galaxy known as NGC 4907 shows its best side from 270 million light-years away to anyone who can see it from the northern hemisphere.This is a new image from the NASA/ESA Hubble Space Telescope of the face-on the galaxy, displaying its beautiful spiral arms, wound loosely around its central bright bar of stars.

Shining brightly below the galaxy is a star that is actually within our own Milky Way galaxy. This star appears much brighter than the many millions of stars in NGC 4907 as it is 100 000 times closer, residing only 2500 light-years away.

NGC 4907 is also part of the Coma Cluster, a group of over 1000 galaxies, some of which can be seen around NGC 4907 in this image. This massive cluster of galaxies lies within the constellation of Coma Berenices, which is named for the locks of Queen Berenice II of Egypt: the only constellation named after a historical person.

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

This striking, high-resolution image of the Arc de Triomphe, in Paris, was captured by Planet SkySat – a fleet of satellites that have just joined ESA’s Third Party Mission Programme in April 2022.

The Arc de Triomphe, or in full Arc de Triomphe de l’Étoile, is an iconic symbol of France and one of the world’s best-known commemorative monuments. The triumphal arch was commissioned by Napoleon I in 1806 to celebrate the military achievements of the French armies. Construction of the arch began the following year, on 15 August (Napoleon’s birthday).

The arch stands at the centre of the Place Charles de Gaulle, the meeting point of 12 grand avenues which form a star (or étoile), which is why it is also referred to as the Arch of Triumph of the Star. The arch is 50 m high and 45 m wide.

The names of all French victories and generals are inscribed on the arch’s inner and outer surfaces, while the Tomb of the Unknown Soldier from World War I lies beneath its vault. The tomb’s flame is rekindled every evening as a symbol of the enduring nature of the commemoration and respect shown to those who have fallen in the name of France.

The Arc de Triomphe’s location at the Place Charles de Gaulle places it at the heart of the capital and the western terminus of the Avenue des Champs-Élysées (visible in the bottom-right of the image). Often referred to as the ‘most beautiful avenue in the world’, the Champs-Élysées is known for its theatres, cafés and luxury shops, as the finish of the Tour de France cycling race, as well as for its annual Bastille Day military parade.

This image, captured on 9 April 2022, was provided by Planet SkySat – a fleet of 21 very high-resolution satellites capable of collecting images multiple times during the day. SkySat’s satellite imagery, with 50 cm spatial resolution, is high enough to focus on areas of great interest, identifying objects such as vehicles and shipping containers.

SkySat data, along with PlanetScope (both owned and operated by Planet Labs), serve numerous commercial and governmental applications. These data are now available through ESA’s Third Party Mission programme – enabling researchers, scientists and companies from around the world the ability to access Planet’s high-frequency, high-resolution satellite data for non-commercial use.

Within this programme, Planet joins more than 50 other missions to add near-daily PlanetScope imagery, 50 cm SkySat imagery, and RapidEye archive data to this global network.

Peggy Fischer, Mission Manager for ESA’s Third Party Missions, commented, “We are very pleased to welcome PlanetScope and SkySat to ESA’s Third Party Missions portfolio and to begin the distribution of the Planet data through the ESA Earthnet Programme.

“The high-resolution and high-frequency imagery from these satellite constellations will provide an invaluable resource for the European R&D and applications community, greatly benefiting research and business opportunities across a wide range of sectors.”

To find out more on how to apply to the Earthnet Programme and get started with Planet data, click here.

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

Credits: Planet SkySat

Deep Space Antenna 1 is ESA’s first 35-m deep dish, staring out to space to communicate with missions far from home.

Located 140 kilometres north of Perth, Western Australia, close to the village of New Norcia, this giant antenna is in the perfect spot to observe the skies.

“The Wadjarri people from the Murchison region refer to much of the milky way as the emu, as it resembles an emu stretched across the sky,” says Suzy Jackson, Maintenance & Operations Manager for the ground station.

“I’m told that when the emu’s nose reaches the horizon, that’s the best time to collect emu eggs. Having our antenna in the foreground just makes it all the better. I am amazed at how beautiful our workplace here is.”

The New Norcia antenna provides routine support to missions orbiting Mars like Mars Express and Exomars TGO as well as the Gaia space observatory, in the process of making the world's most precise map of the stars in our Milky Way galaxy and BepiColombo on its way to Mercury.

With the launch of ESA’s ESTRACK now 'dashboard’, you can find out exactly which missions are communicating with which antennas at any moment, and discover more about what individual missions are up to - what is their mission and how far away are they?

Explore the ESTRACK network in real time.

Check out our guide to using the dashboard, here.

This processed image was taken by local astrophotographer Jim Longbottom. Find more of his work on his Flickr page.

Credits: Jim Longbottom

Astronomers estimate 50 000 sources of near-infrared light are represented in this image from the NASA/ESA/CSA James Webb Space Telescope. Their light has travelled through various distances to reach the telescope’s detectors, representing the vastness of space in a single image. A foreground star in our own galaxy, to the right of the image centre, displays Webb’s distinctive diffraction spikes. Bright white sources surrounded by a hazy glow are the galaxies of Pandora’s Cluster, a conglomeration of already-massive clusters of galaxies coming together to form a mega cluster. The concentration of mass is so great that the fabric of spacetime is warped by gravity, creating a natural, super-magnifying glass called a 'gravitational lens' that astronomers can use to see very distant sources of light beyond the cluster that would otherwise be undetectable, even to Webb.

These lensed sources appear red in the image, and often as elongated arcs distorted by the gravitational lens. Many of these are galaxies from the early universe, with their contents magnified and stretched out for astronomers to study. Other red sources in the image have yet to be confirmed by follow-up observations with Webb’s Near-Infrared Spectrograph (NIRSpec) instrument to determine their true nature. One intriguing example is an extremely compact source that appears as a tiny red dot, despite the magnifying effect of the gravitational lens. One possibility is that the dot is a supermassive black hole in the early universe. NIRSpec data will provide both distance measurements and compositional details of selected sources, providing a wealth of previously-inaccessible information about the universe and how it has evolved over time.

[Image Description: A crowded galaxy field on a black background, with one large star dominating the image just right of center. Three areas are concentrated with larger white hazy blobs on the left, lower right, and upper right above the single star. Scattered between these areas are many smaller sources of light; some also have a hazy white glow, while many other are red or orange.]

Credits: NASA, ESA, CSA, I. Labbe (Swinburne University of Technology), R. Bezanson (University of Pittsburgh), A. Pagan (STScI)

Water levels on the Rhine River, Europe’s second-largest river, have continued to drop owing to soaring temperatures and lack of rainfall, preventing many vessels from navigating through the waters at full capacity. The Copernicus Sentinel-2 mission captured part of the Rhine River near Cologne.

Flowing from the Swiss Alps to the North Sea, the Rhine River is an important shipping route for many products from grains to chemicals to coal. When water levels drop, cargo vessels need to sail with reduced load, so they don’t run aground.

Water levels at the chokepoint of Kaub, near Frankfurt, fell to 32 cm in depth on Monday, down from 42 cm last week. Ships, however, need around 1.5 m to be able to sail fully loaded making it difficult for larger ships to navigate through the waters. Freight ships continue to sail, but only with around 25% to 35% of the ship’s capacity.

The low water levels are emerging earlier than usual, with the lowest water levels typically recorded in September or October. However, reduced temperatures and predicted rainfall forecasted for this week may offer relief to the Rhine.

The phenomenon facing the Rhine is common across much of Europe after an unusually hot and dry summer – causing wildfires and water shortages.

The Copernicus Sentinel-2 satellites capture high-resolution imagery that provide information about the conditions on Earth, such as plant life, soil and coastal areas. The mission consists of two satellites both of which carry an innovative multispectral imager – a camera that captures optical images over a range of wavelengths beyond visible light.

Credits: contains modified Copernicus Sentinel data (2021-22), processed by ESA, CC BY-SA 3.0 IGO

Tiny galaxy HIPASS J1131–31 peeks out from behind the glare of star TYC 7215-199-1, a Milky Way star positioned between Hubble and the galaxy. One hundred years ago, this fast-moving foreground star would have appeared directly in the line of sight, and the "Peekaboo" galaxy would not have been detectable at all.

With the resolution and sensitivity of the NASA/ESA Hubble Space Telescope, astronomers resolved 60 stars in the galaxy and were struck by the fact that they all appear to be relatively young—a few billion years old or younger. This is very unusual in the nearby universe, which has had about 13 billion years of cosmic history to develop. Peekaboo's stars indicate that it is one of the youngest and least-chemically-enriched galaxies ever detected in the local universe. The small galaxy presents astronomers with a unique opportunity for future in-depth analysis of a chemical environment typically only found in the very distant, early universe, where detailed study of individual stars' chemical makeup is not possible. Peekaboo is, in effect, a direct portal into the past, allowing us to discover what the universe was like near the dawn of time.

Credits: NASA, ESA, G. Anand (STScI), A. Pagan (STScI); CC BY 4.0

This image features the spiral galaxy NGC 691, imaged in fantastic detail by Hubble’s Wide Field Camera 3 (WFC3). This galaxy is the eponymous member of the NGC 691 galaxy group, a group of gravitationally bound galaxies that lie about 120 million light-years from Earth.

Objects such as NGC 691 are observed by Hubble using a range of filters. Each filter only allows certain wavelengths of light to reach Hubble’s WFC3. The images collected using different filters are then coloured by specialised visual artists who can make informed choices about which colour best corresponds to which filter. By combining the coloured images from individual filters, a full-colour image of the astronomical object can be recreated. In this way, we can get remarkably good insight into the nature and appearance of these objects.

Credits: ESA/Hubble & NASA, A. Riess; CC BY 4.0 Acknowledgement: M. Zamani

The galaxy merger Arp-Madore 417-391 steals the spotlight in this image from the NASA/ESA Hubble Space Telescope. The Arp-Madore catalogue is a collection of particularly peculiar galaxies spread throughout the southern sky, and includes a collection of subtly interacting galaxies as well as more spectacular colliding galaxies. Arp-Madore 417-391, which lies around 670 million light-years away in the constellation Eridanus in the southern celestial hemisphere, is one such galactic collision. The two galaxies have been distorted by gravity and twisted into a colossal ring, leaving the cores of the two galaxies nestled side by side.

Hubble used its Advanced Camera for Surveys (ACS) to capture this scene — the instrument is optimised to hunt for galaxies and galaxy clusters in the ancient Universe. Hubble’s ACS has been contributing to scientific discovery for 20 years, and throughout its lifetime it has been involved in everything from mapping the distribution of dark matter to studying the evolution of galaxy clusters.

This image comes from a selection of Hubble observations designed to create a list of intriguing targets for follow-up observations with the NASA/ESA/CSA James Webb Space Telescope, as well as other ground-based telescopes. Astronomers chose a list of previously unobserved galaxies for Hubble to inspect between other scheduled observations. Over time, this lets astronomers build up a menagerie of interesting galaxies while using Hubble’s limited observing time as fully as possible.

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

This NASA/ESA Hubble Space Telescope Picture of the Week features the galaxy NGC 6984, an elegant spiral galaxy in the constellation Indus roughly 200 million light-years away from Earth. The galaxy is a familiar sight for Hubble, having already been captured in 2013. The sweeping spiral arms are threaded through with a delicate tracery of dark lanes of gas and dust, and studded with bright stars and luminous star-forming regions.

These new observations were made following an extremely rare astronomical event — a double supernova in NGC 6984. Supernovae are unimaginably violent explosions on a truly vast scale, precipitated by the deaths of massive stars. These events are powerful but rare and fleeting — a single supernova can outshine its host galaxy for a brief time. The discovery of two supernovae at virtually the same time and location (in astronomical terms) prompted speculation from astronomers that the two supernovae may somehow be physically linked. Using optical and ultraviolet observations from Hubble’s Wide Field Camera 3, astronomers sought to get a better look at the site of the two supernovae, hopefully allowing them to discover if the two supernova explosions were indeed linked. Their findings could give astronomers important clues into the lives of binary stars.

As well as helping to unravel an astronomical mystery, these new observations added more data to the 2013 observations, and allowed this striking new image to be created. The observations — each of which covers only a narrow range of wavelengths — add new details and a greater range of colours to the image.

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

The luminous, hot star Wolf-Rayet 124 (WR 124) is prominent at the centre of the NASA/ESA/CSA James Webb Space Telescope’s composite image combining near-infrared and mid-infrared wavelengths of light. The star displays the characteristic diffraction spikes of Webb’s Near-infrared Camera (NIRCam), caused by the physical structure of the telescope itself. NIRCam effectively balances the brightness of the star with the fainter gas and dust surrounding it, while Webb’s Mid-Infrared Instrument (MIRI) reveals the nebula’s structure.

Background stars and galaxies populate the field of view and peek through the nebula of gas and dust that has been ejected from the ageing massive star to span 10 light-years across space. A history of the star’s past episodes of mass loss can be read in the nebula’s structure. Rather than smooth shells, the nebula is formed from random, asymmetric ejections. Bright clumps of gas and dust appear like tadpoles swimming toward the star, their tails streaming out behind them, blown back by the stellar wind.

This image combines various filters from both Webb imaging instruments, with the colour red assigned to wavelengths of 4.44, 4.7, 12.8, and 18 microns (F444W, F470N, F1280W, F1800W), green to 2.1, 3.35, and 11.3 microns (F210M, F335M, F1130W), and blue to 0.9, 1.5, and 7.7 microns (F090W, F150W, F770W).

[Image Description: A large, bright star shines from the centre with smaller stars scattered throughout the image. A clumpy cloud of material surrounds the central star, with more material above and below than on the sides, in some places allowing background stars to peek through. The cloud material is yellow closer to the star.]

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Credits: NASA, ESA, CSA, STScI, Webb ERO Production Team

A snapshot of the Tarantula Nebula (also known as 30 Doradus) is the most recent Picture of the Week from the NASA/ESA Hubble Space Telescope. The Tarantula Nebula is a large star-forming region of ionised hydrogen gas that lies 161 000 light years from Earth in the Large Magellanic Cloud, and its turbulent clouds of gas and dust can be seen swirling between the region’s bright, newly-formed stars.

The Tarantula Nebula is a familiar site for Hubble. It is the brightest star-forming region in our galactic neighbourhood and home to the hottest, most massive stars known. This makes it a perfect natural laboratory in which to test out theories of star formation and evolution, and a rich variety of Hubble images of this region have been released to the public in recent years. The NASA/ESA/CSA James Webb Space Telescope also recently delved into this region, revealing thousands of never-before-seen young stars.

This new image combines data from two different observing proposals. The first was designed to explore the properties of the dust grains that exist in the void between stars and which make up the dark clouds winding through this image. This proposal, which astronomers named Scylla, complements another Hubble observing proposal called Ulysses and is revealing how interstellar dust interacts with starlight in a variety of environments. This image also incorporates data from an observing programme studying star formation in conditions similar to the early Universe, as well as cataloguing the stars of the Tarantula Nebula for future science with Webb.

[Image description: Wispy, nebulous clouds extend from the lower-left of the image. At the top and right the dark background of space can be seen through the sparse nebula. Along the left and in the corner are many layers of brightly-coloured gas and dark, obscuring dust. A cluster of small, bright blue stars in the same corner expands out across the image. Many much smaller stars cover the background.]

Credits: ESA/Hubble & NASA, C. Murray, E. Sabbi CC BY 4.0

Acknowledgement: Y.-H. Chu

Here we see the spectacular cosmic pairing of the star Hen 2-427 — more commonly known as WR 124 — and the nebula M1-67 which surrounds it. Both objects, captured here by the NASA/ESA Hubble Space Telescope are found in the constellation of Sagitta and lie 15 000 light-years away.

The star Hen 2-427 shines brightly at the very centre of this explosive image and around the hot clumps of gas are ejected into space at over 150 000 kilometres per hour.

Hen 2-427 is a Wolf–Rayet star, named after the astronomers Charles Wolf and Georges Rayet. Wolf–Rayet are super-hot stars characterised by a fierce ejection of mass.

The nebula M1-67 is estimated to be no more than 10 000 years old — just a baby in astronomical terms — but what a beautiful and magnificent sight it makes.

Credits: ESA/Hubble & NASA; CC BY 4.0

Acknowledgement: Judy Schmidt

Space Science image of the week:

Earth is about to pass between the Sun and Jupiter, placing the giant planet opposite the Sun on 7 April. This event is termed ‘opposition’ by astronomers, and takes place roughly every 13 months. This is the length of time Earth takes to travel around the Sun relative to Jupiter’s nearly 12 year orbit about five times further away.

At roughly the same time, Jupiter is at its closest approach to Earth, at 666 million km, which means it appears relatively brighter and larger than at other times of the year.

A few days later, Jupiter will be very close to the full Moon in the night sky, making another spectacular sight to look out for.

Jupiter shines more brightly than any star in the evening sky, and is second brightest to Venus, which is currently dominant before sunrise.

Even a good pair of binoculars will reveal Jupiter as a disc with its four largest satellites: Io, Europa, Ganymede and Callisto. Observe the system on different days and at different times to see the positions of the moons change.

The opposition also affords professional and amateur astronomers with good telescopes the chance to view the planet in greater detail than ever.

Astronomer Damian Peach captured this stunning view through a 1 m-diameter Cassegrain telescope in Chile earlier this year, on 25 February. It shows off Jupiter’s ‘Great Red Spot’ (centre left) as well as the much younger ‘Red Spot Junior’ (lower right), more formally known as Oval BA.

The spots are vast raging storms: the Great Red Spot has prevailed for more than 300 years, and is wider than Earth.

The image also highlights Jupiter’s banded, turbulent atmosphere that is riddled with chaotic cloud formations.

Jupiter and its large icy satellites – Europa, Ganymede and Callisto – are the focus of ESA’s upcoming Jupiter Icy Moons Explorer mission, Juice, which is planned for launch in 2022. It will cruise the Jovian system for three-and-a-half years, including flybys of the moons, as well as orbiting Jupiter and Ganymede.

Previous flybys of these moons have raised the exciting prospect that some of them might harbour subsurface liquid oceans and conditions suitable to support some forms of life, and Juice will further explore this possibility.

Credit: D. Peach/Chilescope team

A small portion of the Small Magellanic Cloud (SMC) is pictured in this image from the NASA/ESA Hubble Space Telescope. The SMC is a dwarf galaxy and one of the Milky Way’s nearest neighbours, lying only about 200 000 light-years from Earth. It makes a pair with the Large Magellanic Cloud, and both objects can be seen from the southern hemisphere, as well as from some northern latitudes.

The Small Magellanic Cloud contains hundreds of millions of stars, but this image focuses on just a small fraction of them. These stars comprise the open cluster NGC 376, which has a total mass only about 3400 times that of the Sun. Open clusters, as the name suggests, are loosely bound and sparsely populated. This distinguishes open clusters from globular clusters, which are often so thronged with stars that they have a continuous blur of starlight at their centres. In the case of NGC 376, individual stars can be picked out clearly even in the most densely populated parts of this image.

The data in this image come from two different astronomical investigations which relied on two of Hubble’s instruments: the Wide Field Camera 3 (WFC3) and the Advanced Camera for Surveys (ACS). The first investigation used the ACS to explore a handful of star clusters in the Small Magellanic Cloud and help astronomers explore topics including the abundance of low- and high-mass stars in different environments. The second investigation used both the WFC3 and ACS, and aimed to answer fundamental questions about the lives of stars and help astronomers understand precisely where, when, why and how stars form.

[Image description: A large number of bright stars, each with a cross-shape extending from its centre. In the centre there is a dense collection of foreground stars. Five are orange and the rest are blue. The black background is filled with small stars — most of them, however, larger than a single point.]

Credits: ESA/Hubble & NASA, A. Nota, G. De Marchi; CC BY 4.0

The spiral arms of the galaxy NGC 3318 are lazily draped across this image from the NASA/ESA Hubble Space Telescope. This spiral galaxy lies in the constellation Vela and is roughly 115 light-years away from Earth. Vela was originally part of a far larger constellation, known as Argo Navis after the fabled ship Argo from Greek mythology, but this unwieldy constellation proved to be impractically large. Argo Navis was split into three separate parts called Carnina, Puppis, and Vela — each named after part of the Argo. As befits a galaxy in a nautically inspired constellation, the outer edges of NGC 3318 almost resemble a ship’s sails billowing in a gentle breeze.

Despite its placid appearance, NGC 3318 has played host to a spectacularly violent astronomical phenomenon, a titanic supernova first detected by an amateur astronomer in 2000. Thanks to NGC 3318’s distance from Earth, the original supernova must have taken place in or around 1885. Coincidentally, this was the year in which the only supernova ever to be detected in our neighbouring galaxy Andromeda was witnessed by 19th-century astronomers.

Credits: ESA/Hubble & NASA, ESO, R. J. Foley; CC BY 4.0

Acknowledgement: R. Colombari

The somewhat amorphous spiral galaxy UGC 2890 appears side-on in this image from the NASA/ESA Hubble Space Telescope, with bright foreground stars studding the image. This galaxy lies around 30 million light-years away in the constellation Camelopardalis. In 2009 astronomers spotted a catastrophically powerful supernova explosion in UGC 2890. While the supernova itself has long since faded from view, Hubble recently took a break from its regular observing schedule to inspect the aftermath of this explosive event.

A Type II supernova is a spectacularly energetic explosion that marks the violent death of a massive star. As it runs out of the elements necessary to fuel nuclear fusion, the core of a massive star flickers out and stops producing energy. With nothing to support the crushing force of gravity, the core of the star shrinks and then suddenly implodes, leaving the star’s outer layers to collapse inwards and rebound out into space as a supernova explosion.

This observation is one of many Hubble investigations of Type II supernovae. Astronomers turned to Hubble’s Advanced Camera for Surveys to explore the surroundings of Type II supernovae in the hope of discovering the ages and masses of stars in the neighbourhood. This will reveal insights into the types of stars that eventually create Type II supernovae, as well as revealing any stellar survivors of colossal supernova explosions.

[Image description: A spiral galaxy is seen edge-on and tilted at an angle. The body of the galaxy is blue and obscured by threads of dark red dust, and it is surrounded by a pale glow. Three stars with prominent cross-shaped diffraction spikes are very bright in the foreground. The background is dark and sparsely-covered in small stars.]

Credits: ESA/Hubble & NASA, C. Kilpatrick; CC BY 4.0

This week’s Hubble/ESA Picture of the Week features NGC 7678 — a galaxy located approximately 164 million light-years away in the constellation of Pegasus (The Winged Horse). With a diameter of around 115 000 light-years, this bright spiral galaxy is a similar size to our own galaxy (the Milky Way), and was discovered in 1784 by the German-British astronomer William Herschel.

The Atlas of Peculiar Galaxies is a catalogue which was produced in 1966 by the American astronomer Halton Arp. NGC 7678 is among the 338 galaxies presented in this catalogue, which organises peculiar galaxies according to their unusual features. Catalogued here as Arp 28, this galaxy is listed together with six others in the group “spiral galaxies with one heavy arm”.

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

This image from the NASA/ESA Hubble Space Telescope features the spectacular galaxy NGC 2442.

This galaxy was host to a supernova explosion, known as SN2015F, that was created by a white dwarf star. The white dwarf was part of a binary star system and syphoned mass from its companion, eventually becoming too greedy and taking on more than it could handle. This unbalanced the star and triggered runaway nuclear fusion that eventually led to an intensely violent supernova explosion.

SN2015F was spotted in March 2015 in the galaxy named NGC 2442, nicknamed the Meathook Galaxy owing to its extremely asymmetrical and irregular shape. The supernova shone brightly for quite some time and was easily visible from Earth through even a small telescope until later that summer.

Credits: ESA/Hubble & NASA, S. Smartt et al.; CC BY 4.0