Picture of the Week

2 June 2025: A galaxy ablaze with young stars is the subject of today’s NASA/ESA Hubble Space Telescope Picture of the Week. This galaxy is called NGC 685 and is situated about 64 million light-years away in the constellation Eridanus (The River). NGC 685 is classified as a barred spiral because its feathery spiral arms sprout from the ends of a bar of stars at the galaxy’s centre. The Milky Way is also a barred spiral, but our galaxy is a little less than twice the size of NGC 685. Astronomers used Hubble to study NGC 685 for two observing programmes, both of which focus on star formation. It’s no surprise that NGC 685 was chosen for these programmes: numerous patches of young blue stars highlight the galaxy’s spiral arms. Many of these star clusters are cocooned in pink gas clouds, which are called H II (pronounced ‘H-two’) regions. An H II region …

26 May 2025: A single member of a galaxy pair takes centre stage in this NASA/ESA Hubble Space Telescope Picture of the Week. This beautiful spiral galaxy is NGC 3507, which is situated about 46 million light-years away in the constellation Leo. NGC 3507 is classified as a barred spiral because the galaxy’s sweeping spiral arms emerge from the ends of a central bar of stars rather than the central point of the galaxy. Though pictured solo here, NGC 3507 actually travels the Universe with a galactic partner named NGC 3501 that is located outside the frame. NGC 3501 was featured in a previous Picture of the Week. While NGC 3507 is a quintessential galactic pinwheel, its partner resembles a streak of quicksilver across the sky. Despite looking completely different, both are spiral galaxies, simply seen from different angles. For galaxies that are just a few tens of millions of light-years away, like …

19 May 2025: The stately and inclined spiral galaxy NGC 3511 is the subject of this NASA/ESA Hubble Space Telescope Picture of the Week. The galaxy is located 43 million light-years away in the constellation Crater (The Cup). From Hubble’s vantage point in orbit around Earth, NGC 3511 is tilted by about 70 degrees, intermediate between face-on galaxies that display picture-perfect spiral arms and edge-on galaxies that reveal only their dense, flattened discs. Astronomers are studying NGC 3511 as part of a survey of the star formation cycle in nearby galaxies. For this observing programme, Hubble will record the appearance of 55 local galaxies using five filters that allow in different wavelengths, or colours, of light. One of these filters allows only a specific wavelength of red light to pass through. Giant clouds of hydrogen gas glow in this red colour when energised by ultraviolet light from hot young stars. As this image …

12 May 2025: Today’s NASA/ESA Hubble Space Telescope Picture of the Week features a sparkling cloudscape from one of the Milky Way’s galactic neighbours, a dwarf galaxy called the Large Magellanic Cloud. Located 160 000 light-years away in the constellations Dorado and Mensa, the Large Magellanic Cloud is the largest of the Milky Way’s many small satellite galaxies. This view of dusty gas clouds in the Large Magellanic Cloud is possible thanks to Hubble’s cameras, such as the Wide Field Camera 3 (WFC3) that was used to collect the observations for this image. WFC3 is equipped with a variety of filters, each of which lets through only specific wavelengths, or colours, of light. This image combines observations made with five different filters, including some that capture ultraviolet and infrared light that the human eye cannot see. The wispy gas clouds in this image resemble brightly coloured candyfloss. When viewing such a vividly coloured …

5 May 2025: The spiral galaxy NGC 3596 is on display in this NASA/ESA Hubble Space Telescope Picture of the Week, which incorporates six different wavelengths of light. NGC 3596 is situated 90 million light-years from Earth in the constellation Leo. The galaxy was discovered in 1784 by astronomer William Herschel, the namesake of ESA’s Herschel Space Observatory. NGC 3596 appears almost perfectly face-on when viewed from Earth, showcasing the galaxy’s neatly wound spiral arms. The bright arms mark where the galaxy’s stars, gas and dust are concentrated. Star formation is also most active in a galaxy’s spiral arms, as shown by the brilliant pink star-forming regions and young blue stars tracing NGC 3596’s arms in this image. What causes these spiral arms to form? It’s a surprisingly difficult question to answer, partly because of the remarkable diversity of spiral galaxies. Some have clear spiral arms, while others have patchy, feathery arms. Some …

28 April 2025: A beautiful but skewed spiral galaxy dazzles in today’s NASA/ESA Hubble Space Telescope Picture of the Week. This galaxy, called Arp 184 or NGC 1961, sits about 190 million light-years away from Earth in the constellation Camelopardalis (The Giraffe). The name Arp 184 comes from the Atlas of Peculiar Galaxies, which was compiled by astronomer Halton Arp in 1966. The 338 galaxies in the atlas are oddly shaped, tending to be neither entirely elliptical nor entirely spiral-shaped. Many of the galaxies are in the process of interacting with other galaxies, while others are dwarf galaxies without well-defined structures. Arp 184 earned its spot in the catalogue thanks to its single broad, star-speckled spiral arm that appears to stretch toward us. The galaxy’s far side sports a few wisps of gas and stars but lacks a similarly impressive spiral arm. This Hubble image combines data from three Snapshot observing programmes, which …

21 April 2025: As part of ESA/Hubble’s 35th anniversary celebrations, a new image series has been shared throughout April to revisit stunning Hubble targets that were previously released. New images of NGC 346, the Sombrero Galaxy, and the Eagle Nebula have already been published. Now, ESA/Hubble is revisiting the star cluster Messier 72 (M72) with new data and image processing techniques. M72 is a particularly special target because it was the first image ever published in the ESA/Hubble Picture of the Week series, on 22 April 2010. For fifteen years, the ESA/Hubble team has been publishing a new Hubble image every Monday for everyone to enjoy. This has resulted in nearly 800 images being added to the vast Hubble image archive over the years. M72 is a collection of stars, formally known as a globular cluster, located in the constellation Aquarius roughly 50 000 light years from Earth. The intense gravitational attraction between …

14 April 2025: Today’s rather aquatic-themed NASA/ESA Hubble Space Telescope Picture of the Week features the spiral galaxy Messier 77, also known as the Squid Galaxy, which sits 45 million light-years away in the constellation Cetus (The Whale). The designation Messier 77 comes from the galaxy’s place in the famous catalogue compiled by the French astronomer Charles Messier. Another French astronomer, Pierre Méchain, discovered the galaxy in 1780. Both Messier and Méchain were comet hunters who catalogued nebulous objects that could be mistaken for comets. Messier, Méchain, and other astronomers of their time mistook the Squid Galaxy for either a spiral nebula or a star cluster. This mischaracterisation isn’t surprising. More than a century would pass between the discovery of the Squid Galaxy and the realisation that the ‘spiral nebulae’ scattered across the sky were not part of our galaxy and were in fact separate galaxies millions of light-years away. The Squid Galaxy’s …

7 April 2025: The swirling, paint-like clouds in the darkness of space in this stunning image seem surreal, like a portal to another world opening up before us. In fact, the subject of this ESA/Hubble Picture of the Week is very real. We are seeing vast clouds of ionised atoms and molecules, thrown into space by a dying star. This is a planetary nebula named Kohoutek 4-55, a member of the Milky Way galaxy situated just 4600 light-years away in the constellation Cygnus (the Swan). Planetary nebulae are the spectacular final display at the end of a giant star’s life. Once a red giant star has exhausted its available fuel and shed its last layers of gas, its compact core will contract further, enabling a final burst of nuclear fusion. The exposed core reaches extremely hot temperatures, radiating very energetic ultraviolet light that energises the enormous clouds of cast-off gas. Molecules in the …

31 March 2025: This NASA/ESA Hubble Space Telescope Picture of the Week features the picturesque spiral galaxy NGC 4941, which lies about 67 million light-years from Earth in the constellation Virgo (The Maiden). Because this galaxy is nearby, cosmically speaking, Hubble’s keen instruments are able to pick out exquisite details such as individual star clusters and filamentary clouds of gas and dust. The data used to construct this image were collected as part of an observing programme that investigates the star formation and stellar feedback cycle in nearby galaxies. As stars form in dense, cold clumps of gas, they begin to influence their surroundings. Stars heat and stir up the gas clouds in which they are born through winds, starlight, and — eventually, for massive stars — by exploding as supernovae. These processes are collectively called stellar feedback, and they impact the rate at which a galaxy can form new stars. As it …

24 March 2025: The subject of today’s NASA/ESA Hubble Space Telescope Picture of the Week is the stunning spiral galaxy NGC 5530. NGC 5530 is situated 40 million light-years away in the constellation Lupus (The Wolf). This galaxy is classified as a ‘flocculent’ spiral, meaning that its spiral arms are patchy and indistinct. While some galaxies have extraordinarily bright centres where they host a feasting supermassive black hole, the bright source near the centre of NGC 5530 is not an active black hole but instead a star within our own galaxy, only 10 thousand light-years from Earth. This chance alignment gives the appearance that the star is at the dense heart of NGC 5530. If you had pointed a backyard telescope at NGC 5530 on the evening of 13 September 2007, you would have seen another bright point of light adorning the galaxy. That night, Australian amateur astronomer Robert Evans discovered a supernova, …

17 March 2025: Say hello to one of the Milky Way’s neighbours! Today’s NASA/ESA Hubble Space Telescope Picture of the Week features a scene from one of the closest galaxies to the Milky Way, the Small Magellanic Cloud (SMC). The SMC is a dwarf galaxy located about 200 000 light-years away. Most of the galaxy resides in the constellation Tucana, but a small section crosses over into the neighbouring constellation Hydrus. Thanks to its proximity, the SMC is one of only a few galaxies that can be seen from Earth without the help of a telescope or binoculars. For viewers in the southern hemisphere and some latitudes in the northern hemisphere, the SMC resembles a piece of the Milky Way that has broken off, though in reality it’s much farther away than any part of our own galaxy. With its 2.4-metre ‘eye’ and sensitive instruments, Hubble’s view of the SMC is far more …

10 March 2025: This NASA/ESA Hubble Space Telescope Picture of the Week features a sparkling spiral galaxy paired with a prominent star, both in the constellation Virgo. While the galaxy and the star appear to be close to one another, even overlapping, they’re actually a great distance apart. The star, which is marked with four long diffraction spikes, is in our own galaxy. It’s just 7109 light-years away from Earth. The galaxy, which is named NGC 4900, lies about 45 million light-years from Earth. This image combines data from two of Hubble’s instruments: the Advanced Camera for Surveys, which was installed in 2002 and is still in operation today, and the older Wide Field and Planetary Camera 2, which was in use from 1993 to 2009. The data used here were taken more than 20 years apart for two different observing programmes — a real testament to Hubble’s long scientific lifetime! Both programmes …

3 March 2025: This vibrant spiral galaxy and the subject of today’s NASA/ESA Hubble Space Telescope Picture of the Week is NGC 5042, which resides about 48 million light-years from Earth in the constellation Hydra (the water snake). The galaxy nicely fills the frame of this Hubble image, with a single Milky Way star marked by cross-shaped diffraction spikes attempting to blend in with the bright stars along the galaxy’s edge. Hubble observed NGC 5042 in six wavelength bands from the ultraviolet to the infrared to create this multicoloured portrait. The galaxy’s cream-coloured centre is packed with ancient stars, and the galaxy’s spiral arms are decorated with patches of young blue stars. The elongated yellow-orange objects that are scattered around the image are background galaxies far more distant than NGC 5042. Perhaps NGC 5042’s most striking feature is its collection of brilliant pink gas clouds that are studded throughout its spiral arms. These …

24 February 2025: In this NASA/ESA Hubble Space Telescope Picture of the Week, Hubble has once again lifted the veil on a famous — and frequently photographed — supernova remnant: the Veil Nebula. This nebula is the remnant of a star roughly 20 times as massive as the Sun that exploded about 10 000 years ago. Situated about 2400 light-years away in the constellation Cygnus, this photogenic nebula made an appearance as the Picture of the Week previously in 2021. This view combines images taken in three different filters by Hubble’s Wide Field Camera 3 instrument, highlighting emission from hydrogen, sulphur and oxygen atoms. This image shows just a small fraction of the Veil Nebula; if you could see the entire nebula without the aid of a telescope, it would be as wide as six full Moons placed side by side. Look in the sidebar of this page to see this image superimposed …

17 February 2025: The sparkling spiral galaxy gracing this NASA/ESA Hubble Space Telescope Picture of the Week is UGC 5460, which sits about 60 million light-years away in the constellation Ursa Major. This image combines four different wavelengths of light to reveal UGC 5460’s central bar of stars, winding spiral arms and bright blue star clusters. Also captured in the upper left-hand corner of this image is a far closer object: a star just 577 light-years away in our own galaxy. UGC 5460 has hosted two recent supernovae named SN 2011ht and SN 2015as. It’s because of these two stellar explosions that Hubble targeted this galaxy, collecting data for three observing programmes that aim to study various kinds of supernovae. SN 2015as was what’s known as a core-collapse supernova: a cataclysmic explosion that happens when the core of a star far more massive than the Sun runs out of fuel and collapses under …

10 February 2025: The Universe is a dusty place, as this NASA/ESA Hubble Space Telescope Picture of the Week shows. Featured in this image are swirling clouds of gas and dust near the Tarantula Nebula in the Large Magellanic Cloud. About 160 000 light-years away in the constellations Dorado and Mensa, the Large Magellanic Cloud is one of the nearest galaxies to the Milky Way. The Tarantula Nebula is the most productive star-forming region in the nearby Universe, home to the most massive stars known. The colourful gas clouds of this nebula are crossed by wispy tendrils and dark clumps of dust. This dust is different from ordinary household dust, which can be made of bits of soil, skin cells, hair and even plastic. Cosmic dust tends to be made of carbon or of molecules called silicates, which contain silicon and oxygen. The data used to create this image were collected as part …

3 February 2025: A supernova and its host galaxy are the subject of today’s NASA/ESA Hubble Space Telescope Picture of the Week. The galaxy in question is LEDA 132905, which is situated in the constellation Sculptor. Even at over 400 million light-years away, LEDA 132905’s spiral structure is faintly visible, as are patches of bright blue stars. The bright white dot directly in the centre of the image, between the bright centre of the galaxy and its faint left edge, is a supernova named SN 2022abvt. SN 2022abvt was discovered in late 2022, and Hubble observed the explosion about two months later. This image was constructed from data collected to study Type Ia supernovae, which occur when the exposed core of a dead star ignites in a sudden, destructive burst of nuclear fusion. Researchers are interested in this type of supernova because they can be used to measure precise distances to other galaxies. …

27 January 2025: The subject of this NASA/ESA Hubble Space Telescope Picture of the Week is a supernova-hosting galaxy located about 600 million light-years away in the constellation Gemini. This picture was taken roughly two months after a supernova named SN 2022aajn was discovered in this galaxy. The supernova is visible as a blue dot at the centre of the image, brightening the hazy body of the galaxy. Other than the announcement of its discovery in November 2022, SN 2022aajn has never been the subject of published research. Why, then, would Hubble observe this supernova? SN 2022aajn is what’s known as a Type Ia supernova, which results from the explosion of the core of a dead star. Supernovae of this type help astronomers measure the distance to faraway galaxies. This is possible because Type Ia supernovae are thought to be of the same intrinsic luminosity — no matter how bright they seem from …

20 January 2025: Today’s NASA/ESA Hubble Space Telescope Picture of the Week features a dusty yet sparkling scene from one of the Milky Way’s satellite galaxies, the Large Magellanic Cloud. The Large Magellanic Cloud is a dwarf galaxy situated about 160 000 light-years away in the constellations Dorado and Mensa. Despite being only 10–20% as massive as the Milky Way galaxy, the Large Magellanic Cloud contains some of the most impressive star-forming regions in the nearby Universe. The scene pictured here is on the outskirts of the Tarantula Nebula, the largest and most productive star-forming region in the local Universe. At its centre, the Tarantula Nebula hosts the most massive stars known, which weigh in at roughly 200 times the mass of the Sun. The section of the nebula shown here features serene blue gas, brownish-orange dust patches and a sprinkling of multicoloured stars. The stars within and behind the dust clouds appear …

13 January 2025: Today’s NASA/ESA Hubble Space Telescope Picture of the Week peers into the dusty recesses of the nearest massive star-forming region to Earth, the Orion Nebula. Just 1300 light-years away, the Orion Nebula is visible to the naked eye below the three stars that form the ‘belt’ in the constellation Orion. The nebula is home to hundreds of newborn stars including the subject of this image: the protostars HOPS 150 and HOPS 153. These protostars get their names from the Herschel Orion Protostar Survey, which was carried out with ESA’s Herschel Space Observatory. The object that can be seen in the upper-right corner of this image is HOPS 150: it’s a binary system, two young protostars orbiting each other. Each has a small, dusty disc of material surrounding it that it is feeding from. The dark line that cuts across the bright glow of these protostars is a cloud of gas …

6 January 2025: This week’s NASA/ESA Hubble Space Telescope Picture of the Week shows a tiny patch of sky in the constellation Hydra. The stars and galaxies depicted here span a mind-bending range of distances. Nearest to us in this image are stars within our own Milky Way galaxy, which are marked by diffraction spikes. The bright star that sits just at the edge of the prominent bluish galaxy is only 3230 light-years away, as measured by ESA's Gaia space observatory. Behind this star is a galaxy named LEDA 803211. At 622 million light-years distant, this galaxy is close enough that its bright galactic nucleus is clearly visible, as are numerous star clusters scattered around its patchy disc. Many of the more distant galaxies in this frame appear star-like, with no discernible structure, but without the diffraction spikes of a star in our galaxy. Of all the galaxies in this frame, one pair …

30 December 2024: This NASA/ESA Hubble Space Telescope Picture of the Week features the galaxy LEDA 22057, which is located about 650 million light-years away in the constellation Gemini. Like the subject of last week’s Picture of the Week, LEDA 22057 is the site of a supernova explosion. This particular supernova, named SN 2024PI, was discovered by an automated survey in January 2024. The survey covers the entire northern half of the night sky every two days and has catalogued more than 10 000 supernovae. The supernova is visible in this image: located just down and to the right of the galactic nucleus, the pale blue dot of SN 2024PI stands out against the galaxy’s ghostly spiral arms. This image was taken about a month and a half after the supernova was discovered, so the supernova is seen here many times fainter than its maximum brilliance. SN 2024PI is classified as a Type …

23 December 2024: The subject of this NASA/ESA Hubble Space Telescope Picture of the Week is the spiral galaxy NGC 337, located about 60 million light-years away in the constellation Cetus (The Whale). This image combines observations made at two wavelengths, highlighting the galaxy’s golden centre and blue outskirts. The golden central glow comes from older stars, while the sparkling blue edges get their colour from young stars. If Hubble had observed NGC 337 about a decade ago, the telescope would have spotted something remarkable among the hot blue stars along the galaxy’s edge: a brilliant supernova. The supernova, named SN 2014cx, is remarkable for having been discovered nearly simultaneously in two vastly different ways: by a prolific supernova hunter, Koichi Itagaki, and by the All Sky Automated Survey for SuperNovae (ASAS-SN). ASAS-SN is a worldwide network of robotic telescopes that scans the sky for sudden events like supernovae. Researchers have determined that …

16 December 2024: Featured in this NASA/ESA Hubble Space Telescope Picture of the Week is the spiral galaxy NGC 2566, which sits 76 million light-years away in the constellation Puppis. A prominent bar of stars stretches across the centre of this galaxy, and spiral arms emerge from each end of the bar. Because NGC 2566 appears tilted from our perspective, its disc takes on an almond shape, giving the galaxy the appearance of a cosmic eye. As NGC 2566 gazes at us, astronomers gaze right back, using Hubble to survey the galaxy’s star clusters and star-forming regions. The Hubble data are especially valuable for studying stars that are just a few million years old; these stars are bright at the ultraviolet and visible wavelengths to which Hubble is sensitive. Using these data, researchers will measure the ages of NGC 2566’s stars, helping to piece together the timeline of the galaxy’s star formation and …

9 December 2024: Today’s NASA/ESA Hubble Space Telescope Picture of the Week features the glorious spiral galaxy NGC 5643, which is located roughly 40 million light-years away in the constellation Lupus. NGC 5643 is what’s known as a grand design spiral, referring to how the galaxy’s two large, winding spiral arms are clear to see. The spiral arms are defined by bright blue stars, lacy reddish-brown dust clouds and pink star-forming regions. As fascinating as the galaxy appears at visible wavelengths, some of NGC 5643’s most interesting features are invisible to the human eye. Ultraviolet and X-ray images and spectra of NGC 5643 show that the galaxy hosts an active galactic nucleus: an especially bright galactic core powered by a feasting supermassive black hole. When a supermassive black hole ensnares gas from its surroundings, the gas collects in a disc that heats up to hundreds of thousands of degrees. The superheated gas shines …

2 December 2024: The subject of this NASA/ESA Hubble Space Telescope Picture of the Week is NGC 1637, a spiral galaxy located 38 million light-years from Earth in the constellation Eridanus. This image comes from an observing programme dedicated to studying star formation in nearby galaxies. Stars form in cold, dusty gas clouds that collapse under their own gravity. As young stars grow, they heat their nurseries through starlight, winds, and powerful outflows. Together, these factors play a role in controlling the rate at which future generations of stars form. Evidence of star formation is scattered all around NGC 1637, if you know where to look. The galaxy’s spiral arms are dotted with what appear to be pink clouds, many of which are accompanied by bright blue stars. The pinkish colour comes from hydrogen atoms that have been excited by ultraviolet light from young, massive stars. This contrasts with the warm yellow glow …

25 November 2024: Featured in this new NASA/ESA Hubble Space Telescope Picture of the Week is the spiral galaxy NGC 2090, located in the constellation Columba. This galaxy is notable as a part of the group of galaxies studied in Hubble’s Extragalactic Distance Scale Key Project, which aimed to determine a new state-of-the-art value for the Hubble constant, one of the then-new telescope’s primary science goals. The contribution of NGC 2090 was in calibrating the Tully-Fisher (TF) distance method, by observing Cepheid variable stars in the galaxy. The Cepheid-based measurement from that study in 1998 put NGC 2090 as 37 million light-years away; the newest measurement from 2020, using the TF method, has NGC 2090 slightly farther away, at 40 million light-years. Before and since that project, NGC 2090 has been well studied as a very prominent nearby example of star formation. It has been described as a flocculent spiral, meaning a spiral …

18 November 2024: What kind of astronomical object is this? It doesn’t look quite like the kinds of galaxies, nebulae, star clusters or galaxy clusters which Hubble normally brings us images of. In fact, this is a spiral galaxy, named UGC 10043 — we just happen to be seeing it directly from the side! Located roughly 150 million light-years from Earth in the constellation Serpens, UGC 10043 is one of the somewhat rare spiral galaxies that are seen edge-on. From this point of view, we see the galaxy’s disc as a sharp line through space, overlain with a prominent dust lane. This dust is spread across the spiral arms of UGC 10043, but it looks very thick and cloudy when viewed from the side. You can even see the lights of some active star-forming regions in the arms, shining out from behind the dust. Strikingly, we can also see that the centre of …

11 November 2024: Previously the Hubble Picture of the Week series has featured a jewel in the queen’s hair — a spiral galaxy in the constellation Coma Berenices, named for the hair of the historical Egyptian queen. However, that galaxy is only one of many known in this constellation. This week’s new image from the NASA/ESA Hubble Space Telescope depicts the cosmic tangle that is MCG+05-31-045, a pair of interacting galaxies located 390 million light-years away and a part of the so-called Coma galaxy cluster. The Coma cluster is a particularly rich cluster and contains over a thousand known galaxies. Several can be easily seen with amateur telescopes. Most of them are elliptical galaxies, and that’s typical of a dense galaxy cluster like the Coma cluster: many elliptical galaxies are formed in close encounters between galaxies that stir them up, or even collisions that rip them apart. While the stars in the interacting …

4 November 2024: This Hubble Picture of the week features NGC 1672, a barred spiral galaxy located 49 million light-years from Earth in the constellation Dorado. This galaxy is a multi-talented light show, showing off an impressive array of different celestial lights. Like any spiral galaxy, its disc is filled with billions of shining stars that give it a beautiful glow. Along its two large arms, bubbles of hydrogen gas are made to shine a striking red light by the powerful radiation of newly-forming stars within. Near to the centre lie some particularly spectacular stars; newly-formed and extremely hot, they are embedded in a ring of hot gas and are emitting powerful X-rays. And in the very centre sits an even more brilliant source of X-rays, an active galactic nucleus created by the heated accretion disc around NGC 1672’s supermassive black hole; this makes NGC 1672 a Seyfert galaxy. But a highlight of …

28 October 2024: This image from the NASA/ESA Hubble Space Telescope features the unbarred spiral galaxy NGC 4414, roughly 51 million light-years away from Earth in the constellation Coma Berenices. You can see an old image of NGC 4414 that features Hubble data from 1995 and 1999 here, which was captured as one of the telescope’s primary missions to determine the distance to galaxies. This was achieved as part of an ongoing research effort to study Cepheid variable stars. Cepheids are a special type of variable star with very stable and predictable brightness variations. The period of these variations depends on physical properties of the stars such as their mass and true brightness. This means that astronomers, just by looking at the variability of their light, can find out about the Cepheids' physical nature, which then can be used very effectively to determine their distance. For this reason cosmologists call Cepheids 'standard candles'. …

21 October 2024: The spiral galaxy appearing in this week’s Hubble Picture of the Week is named IC 3225. It looks remarkably as if it’s been launched from a cannon, speeding through space like a comet with a tail of gas streaming from its disc behind it. The scenes that galaxies appear in from Earth’s point of view are fascinating; many seem to hang calmly in the emptiness of space as if hung from a string, while others star in much more dynamic situations! Appearances can be deceiving with objects so far from Earth — IC 3225 itself is about 100 million light-years away — but the galaxy’s location suggests some causes for this active scene, because IC 3225 is one of over 1300 members of the Virgo galaxy cluster. The density of galaxies in the Virgo cluster creates a rich field of hot gas between them, the so-called ‘intracluster medium’, while the …

14 October 2024: The striking spiral galaxy featured in this week’s Hubble Picture of the Week is Messier 90 (M90, also NGC 4569), located in the constellation Virgo. In 2019, an image of M90 was released using data from the older Wide Field and Planetary Camera 2 — data taken in 1994 soon after the camera’s installation. That image has a distinctive stair-step pattern due to the layout of WFPC2’s sensors. WFPC2 was replaced in 2010 by the Wide Field Camera 3, and Hubble used WFC3 when it turned its aperture to Messier 90 again in 2019 and 2023. The resulting data was processed to create this stunning new image, providing a much fuller view of the galaxy’s dusty disc, its gaseous halo and its bright core. The inner regions of M90’s disc are sites of star formation, which is highlighted here by red H-alpha light from nebulae, but this is absent in …

7 October 2024: The sparkling scene depicted in this week’s Hubble Picture of the Week is of the spiral galaxy NGC 5248, located 42 million light-years from Earth in the constellation Boötes. It is also known as Caldwell 45, having been included in a catalogue of visually interesting celestial objects that were known, but weren’t as commonly observed by amateur astronomers as the more famous Messier objects. NGC 5248 is one of the so-called ‘grand design’ spirals, with prominent spiral arms that reach from near the core out through the disc. It also has a faint bar structure in the centre, between the inner ends of the spiral arms, which is not quite so obvious in this visible-light portrait from Hubble. Features like these which break the rotational symmetry of a galaxy have a huge influence on how matter moves through it, and eventually its evolution through time. They feed gas from a …

30 September 2024: Most galaxies we are familiar with fall into one of two easily-identified types. Spiral galaxies are young and energetic, filled with the gas needed to form new stars and sporting spiral arms hosting hot, bright stars. Elliptical galaxies have a much more pedestrian look, their light coming from a uniform population of older and redder stars. But other galaxies require in-depth study to understand: such is the case with NGC 4694, a galaxy located 54 million light-years from Earth in the Virgo galaxy cluster, and the subject of this Hubble Picture of the Week. NGC 4694 has a smooth-looking, armless disc which — like an elliptical galaxy — is nearly devoid of star formation. However its stellar population is still relatively young and new stars are still actively forming in its core, powering the brightness we can see in this image and giving it a markedly different stellar profile from …

23 September 2024: The spiral galaxy IC 1954, located 45 million light-years from Earth in the constellation Horologium, is the star of this Picture of the Week from the Hubble Space Telescope. It sports a glowing bar in its core, two main majestically winding spiral arms and clouds of dark dust across it. An image of this galaxy was previously released in 2021; this week’s image is entirely new and now includes H-alpha data. The improved coverage of star-forming nebulae, which are prominent emitters of the red H-alpha light, can be seen in the numerous glowing, pink spots across the disc of the galaxy. Interestingly, some astronomers posit that the galaxy’s ‘bar’ is actually an energetic star-forming region that just happens to lie over the galactic centre. The new data featured in this image come from a programme to extend the cooperation between multiple observatories: Hubble, the infrared James Webb Space Telescope, and …

16 September 2024: The magnificent galaxy featured in this Hubble Picture of the Week is NGC 1559. It is a barred spiral galaxy located in the constellation Reticulum near the Large Magellanic Cloud, but much more distant at approximately 35 million light-years from Earth. Hubble last visited this object in 2018. The brilliant light captured in this image offers a wealth of information, which thanks to Hubble can be put to use by both scientists and the public. This picture is composed of a whopping ten different images taken by the Hubble Space Telescope, each filtered to collect light from a specific wavelength or range of wavelengths. It spans Hubble’s sensitivity to light, from ultraviolet around 275 nanometres through blue, green and red to near-infrared at 1600 nanometres. This allows information about many different astrophysical processes in the galaxy to be recorded: a notable example is the red 656-nanometre filter used here. Hydrogen …

9 September 2024: The subject of this Hubble Picture of the Week is a spiral galaxy in the constellation Virgo named NGC 5668. It is relatively near to us at 90 million light-years from Earth and quite accessible for astronomers to study with both space- and ground-based telescopes. At first blush, it doesn’t seem like a remarkable galaxy. It is around 90 000 light-years across, similar in size and mass to our own Milky Way galaxy, and its orientation nearly face-on to us shows open spiral arms made of cloudy, irregular patches. One noticeable difference between the Milky Way galaxy and NGC 5668 is that this galaxy is forming new stars 60% more quickly. This fact belies a galaxy with churning clouds and flows of gas, inclement weather that forms excellent conditions for the formation of new stars! Two main drivers of star formation have been identified by astronomers. Firstly, this high-quality Hubble …

2 September 2024: The Hubble Space Telescope has a lot to show in this week’s Picture of the Week. Its view here is studded with stars, many of which appear particularly large and bright thanks to their nearby locations in our own galaxy, and which feature the characteristic diffraction patterns caused by Hubble’s optics. Much further away — around 240 million light-years distant in fact, in the southern constellation Telescopium — is the spiral galaxy IC 4709. Its swirling disc filled with stars and dust bands is beautifully captured, as is the faint halo surrounding it. The compact region at its core might be the most remarkable sight, however: this is an active galactic nucleus (AGN). If IC 4709’s core were just filled with stars, it would not be nearly so bright. Instead it hosts a gargantuan black hole, 65 million times the mass of our Sun. A disc of gas spirals around …

26 August 2024: Looking past its long spiral arms filled with stars and the dark threads of dust crossing it, your eye might be caught by the shining point at the centre of UGC 3478, the spiral galaxy starring in this Hubble Picture of the Week. This point is the galaxy’s nucleus, and indeed there is something special about it: it is a growing giant black hole which astronomers call an active galactic nucleus, or AGN. UGC 3478, located in the constellation Camelopardalis, is what is known as a Seyfert galaxy. This is a type of galaxy with an AGN at its core. Like all such ‘active galaxies’, the brightness that you see here hides a supermassive black hole at the centre of the galaxy. A disc of gas spirals into this black hole, and as the material crashes together and heats up it emits very strong radiation. The spectrum of this radiation …

19 August 2024: Resting near the centre of the northerly constellation Cepheus, high in the northern sky, is the barred spiral galaxy UGC 11861, the subject of the latest Hubble Picture of the Week. UGC 11861 is located 69 million light-years away from Earth — which may seem a vast distance, but it’s just right for Hubble to grab this majestic shot of the galaxy’s spiral arms and the short but brightly glowing bar in its centre. Among the cloudy gases and the dark wisps of dust, this galaxy is actively forming new stars, visible in the glowing blue patches in its outer arms. This activity has resulted in three supernova explosions being spotted in and nearby UGC 11861, in 1995, 1997 and 2011. The earlier two were both Type II supernovae, a kind which results from the collapse of a massive star at the end of its life. This Hubble image was …

12 August 2024: The subject of this week’s circular Hubble Picture of the Week is situated in the Perseus Cluster, also known as Abell 426, 320 million light-years from Earth. It’s a barred spiral galaxy known as MCG+07-07-072, seen here among a number of photobombing stars that are much closer to Earth than it is. MCG+07-07-072 has quite an unusual shape, for a spiral galaxy, with thin arms emerging from the ends of its barred core to draw a near-circle around its disc. It is classified, using a common extension of the basic Hubble scheme, as an SBc(r) galaxy: the c denotes that its two spiral arms are loosely wound, each only performing a half-turn around the galaxy, and the (r) is for the ring-like structure they create. Rings in galaxies come in quite a few forms, from merely uncommon, to rare and astrophysically important! Lenticular galaxies are a type that sit between …

5 August 2024: This Hubble Picture of the Week features the galaxy LEDA 857074, located in the constellation Eridanus. LEDA 857074 is a barred spiral galaxy, with partially broken spiral arms. It also has a particularly bright spot right in its bar: this is a supernova snapped by Hubble, named SN 2022ADQZ, and quite relevant to this Picture of the Week. The NASA/ESA Hubble Space Telescope has observed a vast range of celestial objects, from galaxies, to nebulae, to star clusters, to planets in the Solar System and beyond. Observing programmes usually seek to gather data so that astronomers can answer a specific question. Naturally, this means most scheduled observations target an object that astronomers have already researched. Some are famous, like the Crab Nebula or the globular cluster Omega Centauri; others might not be so well known to the public, but still be featured in hundreds of scientific papers, such as the …

29 July 2024: The Hubble Picture of the Week this week reveals the subtle glow of the galaxy named IC 3430, located 45 million light-years from Earth in the constellation Virgo. It is part of the Virgo cluster, a rich collection of galaxies both large and small, many of which are very similar in type to this diminutive galaxy. IC 3430 is a dwarf galaxy, a fact well reflected by this view from Hubble, but it is more precisely known as a dwarf elliptical or dE galaxy. Like its larger cousins, this galaxy has a smooth, oval shape lacking any recognisable features like arms or bars, and it is bereft of gas to form very many new stars. Interestingly, IC 3430 does feature a core of hot, massive blue stars, an uncommon sight in elliptical galaxies that indicates recent star-forming activity. It’s believed that ram pressure from the galaxy ploughing through gas within …

22 July 2024: In this week’s Hubble Picture of the Week we are treated to a wonderfully detailed snapshot of NGC 3430. A spiral galaxy, it lies 100 million light-years from Earth in the constellation Leo Minor. Several other galaxies are located relatively nearby to this one, just out of frame; one is close enough that gravitational interaction is driving some star formation in NGC 3430. That NGC 3430 is such a fine example of a galactic spiral may be why it ended up as part of the sample that Edwin Hubble used to define his classification of galaxies. Namesake of the Hubble Space Telescope, in 1926 he authored a paper which classified some four hundred galaxies by their appearance — as either spiral, barred spiral, lenticular, elliptical or irregular. This straightforward typology proved immensely influential, and the modern, more detailed schemes that astronomers use today are still based on it. NGC 3430 …

15 July 2024: The galaxy featured in this week’s Hubble Picture of the Week is the dwarf irregular galaxy NGC 5238, located 14.5 million light-years from Earth in the constellation Canes Venatici. Its unexciting, blob-like appearance, resembling more an oversized star cluster than a galaxy, belies a complicated structure which has been the subject of much research by astronomers. Here, the NASA/ESA Hubble Space Telescope is able to pick out the galaxy’s countless stars, as well as its associated globular clusters — the glowing spots both inside and around the galaxy that are swarmed by yet more stars. NGC 5238 is theorised to have recently — here meaning no more than a billion years ago! — had a close encounter with another galaxy. The evidence for this is the tidal distortions of NGC 5238’s shape, the kind produced by two galaxies pulling on each other as they interact. There’s no nearby galaxy which …

8 July 2024: Measuring the distance to truly remote objects like galaxies, quasars and galaxy clusters is a crucial task in astrophysics, particularly when it comes to studying the early Universe, but it’s a difficult one. Only in the case of a few nearby objects like the Sun, planets and some nearby stars can we measure their distances directly. Beyond that, various indirect methods need to be used; one of the most important is by examining Type Ia supernovae, and this is where the NASA/ESA Hubble Space Telescope comes in. NGC 3810, the galaxy featured in this image, was the host of a Type Ia supernova in 2022. In early 2023 Hubble focused on this and a number of other galaxies to closely examine recent Type Ia supernovae. This kind of supernova results from a white dwarf exploding, and they all have a very consistent brightness. That allows them to be used to …

1 July 2024: This Picture of the Week from the NASA/ESA Hubble Space Telescope depicts the galaxy NGC 4951, a spiral galaxy that’s located 49 million light-years from Earth in the constellation Virgo. The data used to make this image were captured by Hubble as part of a programme to examine how matter and energy travel in nearby galaxies. Galaxies continuously undergo a cycle of star formation whereby the gas in a galaxy forms molecular clouds, which collapse to create new stars, which then disperse the clouds they formed from with powerful radiation or stellar winds in a process called feedback. The remaining gas is left to form new clouds elsewhere. This cycle of moving matter and energy determines how fast a galaxy forms stars and how quickly it burns through its supplies of gas — that is, how it evolves over the course of its life. Understanding this evolution depends on the …

24 June 2024: The focus of this week’s Hubble Picture of the Week is the blue compact dwarf galaxy NGC 5253, located in the constellation Centaurus around 11 million light-years from Earth. This new image combines data taken with Hubble’s Advanced Camera for Surveys (ACS), using its Wide Field Channel, and with the older Wide Field and Planetary Camera 2 (WFPC2). As a bonus for this Picture of the Week, there is also a second new image made using data from the High Resolution Channel (HRC) of ACS, a sub-instrument only operational for a few years that was optimised for detailed studies of environments dense with stars. What has interested astronomers so much about this galaxy that three of Hubble’s instruments were used to study it in depth over ten years? It turns out to lie at the focus of a few areas of research where Hubble’s capabilities are essential. Dwarf galaxies are …

17 June 2024: A visually striking collection of interstellar gas and dust is the focus of this week's Hubble Picture of the Week. Named RCW 7, the nebula is located just over 5300 light-years from Earth in the constellation Puppis. Nebulae are areas of space that are rich in the raw material needed to form new stars. Under the influence of gravity, parts of these molecular clouds collapse until they coalesce into protostars, surrounded by spinning discs of leftover gas and dust. In the case of RCW 7, the protostars forming here are particularly massive, giving off strongly ionising radiation and fierce stellar winds that have transformed it into what is known as a H II region. H II regions are filled with hydrogen ions — where H I refers to a normal hydrogen atom, H II is hydrogen that has lost its electron. The ultraviolet radiation from the massive protostars excites the …

10 June 2024: The globular cluster NGC 2005, featured in this Hubble Picture of the Week, is not unusual in and of itself; but it is a peculiarity in relation to its surroundings. NGC 2005 is located about 750 light-years from the heart of the Large Magellanic Cloud (LMC), which is the Milky Way’s largest satellite galaxy and which itself lies about 162 000 light-years from Earth. Globular clusters are densely-packed clusters that can constitute tens of thousands or millions of stars. Their density means that they are tightly gravitationally bound and are therefore very stable. This stability contributes to their longevity: globular clusters can be billions of years old, and as such often comprise very old stars. Thus, studying globular clusters in space can be a little like studying fossils on Earth: where fossils give insights into the characteristics of ancient plants and animals, globular clusters illuminate the characteristics of ancient stars. …

3 June 2024: This Picture of the Week features the barred spiral galaxy NGC 3059, which lies about 57 million light-years from Earth. The data used to compose this image were collected by Hubble in May 2024, as part of an observing programme that studied a number of galaxies. All the observations were made using the same range of filters: partially transparent materials that allow only very specific wavelengths of light to pass through. Filters are used extensively in observational astronomy, and can be calibrated to allow either extremely narrow or somewhat broader ranges of light through. Narrow-band filters are invaluable from a scientific perspective because certain light wavelengths are associated with specific physical and chemical processes. For example, under particular conditions, hydrogen atoms are known to emit red light with wavelength value of 656.46 nanometres. Red light at this wavelength is known as H-alpha emission, or the ‘H-alpha line’. It is very …

27 May 2024: This week, an image of the broad and sweeping spiral galaxy NGC 4731 is the Hubble Picture of the Week. This galaxy lies among the galaxies of the Virgo cluster, in the constellation Virgo, and is located 43 million light-years from Earth. This highly detailed image was created using six different filters. The abundance of colour illustrates the galaxy's billowing clouds of gas, dark dust bands, bright pink star-forming regions and, most obviously, the long, glowing bar with trailing arms. Barred spiral galaxies outnumber both regular spirals and elliptical galaxies put together, numbering around 60% of all galaxies. The visible bar structure is a result of orbits of stars and gas in the galaxy lining up, forming a dense region that individual stars move in and out of over time. This is the same process that maintains a galaxy's spiral arms, but it is somewhat more mysterious for bars: spiral …

20 May 2024: This Picture of the Week shows the jewel-bright spiral galaxy NGC 4689, which lies 54 million light-years from Earth in the constellation Coma Berenices. This constellation has the distinction of being the only one of the 88 constellations officially recognised by the International Astronomical Union (IAU) to be named after an historical figure, Queen Berenice II of Egypt. The latin word ‘coma’ references her hair, meaning that NGC 4689 can be said to be found in the hair of a queen. Some people of Berenice’s time would have meant this quite literally, as the story goes that her court astronomer thought that a missing lock of Berenice’s hair had been catasterised (a word meaning ‘placed amongst the stars’) by the gods: hence the name of the constellation, Coma Berenices. NGC 4689 holds an interesting — albeit less royal — place in modern astronomy too. The Universe is so incredibly vast …

13 May 2024: Featured in this new image from the NASA/ESA Hubble Space Telescope is a nearly edge-on view of the lenticular galaxy NGC 4753. These galaxies have an elliptical shape and ill-defined spiral arms. This image is the object's sharpest view to date, showcasing Hubble’s incredible resolving power and ability to reveal complex dust structures. NGC 4753 resides around 60 million light-years from Earth in the constellation Virgo and was first discovered by the astronomer William Herschel in 1784. It is a member of the NGC 4753 Group of galaxies within the Virgo II Cloud, which comprises roughly 100 galaxies and galaxy clusters. This galaxy is believed to be the result of a galactic merger with a nearby dwarf galaxy roughly 1.3 billion years ago. NGC 4753’s distinct dust lanes around its nucleus are believed to have been accreted from this merger event. It is now believed that most of the mass …

6 May 2024: The celestial object showcased in this week's Hubble Picture of the Week is the spiral galaxy UGC 9684, which lies around 240 million light-years from Earth in the constellation Boötes. This image shows an impressive example of several classic galactic features, including a clear bar in the galaxy's centre, and a halo surrounding its disc. The impetus for this Hubble image was a study into the host galaxies of Type-II supernovae. These cataclysmic stellar explosions take place throughout the Universe, and are of great interest to astronomers, so automated surveys scan the night sky and attempt to catch sight of them. The supernova which brought UGC 9684 to Hubble's attention occurred during 2020. It has faded from view in this image, which was taken in 2023. Remarkably, the 2020 supernova in this galaxy isn't the only one that's been seen there — four supernova-like events have been spotted in UGC …

29 April 2024: Featured in this Hubble Picture of the Week this week is the dwarf galaxy IC 776. This swirling collection of stars new and old is located in the constellation Virgo — in fact, in the Virgo galaxy cluster — 100 million light-years from Earth. While a dwarf galaxy, it's also been classified as an SAB-type or ‘weakly barred’ spiral, one study naming it a “complex case” in morphology. This highly detailed view from Hubble demonstrates that complexity well. IC 776 has a ragged, disturbed disc that nevertheless looks to spiral around the core, and arcs of star-forming regions. This image is from an observation programme dedicated to the study of dwarf galaxies in the Virgo cluster, searching for sources of X-rays in such galaxies. X-rays are often emitted by accretion discs, where material that is drawn into a compact object by gravity crashes together and forms a hot, glowing disc. …

22 April 2024: This Hubble Picture of the Week depicts the spiral galaxy ESO 422-41, which lies about 34 million light-years from Earth in the constellation Columba. The patchy, star-filled structure of the galaxy’s spiral arms and the glow from its dense core are laid out in intricate detail here by Hubble’s Advanced Camera for Surveys. Images of this galaxy have, however, a decades-long history. The name ESO 422-41 comes from its identification in the European Southern Observatory (B) Atlas of the Southern Sky. In the times before automated sky surveys with space observatories such as ESA’s Gaia, many stars, galaxies and nebulae were discovered by means of large photographic surveys. Astronomers used the most advanced large telescopes of the time to produce hundreds of photographs, covering an area of the sky. They later studied the resulting photographs, attempting to catalogue all the new astronomical objects revealed. In the 1970s a new telescope …

15 April 2024: This image features NGC 3783, a bright barred spiral galaxy about 130 million light-years from Earth, that also lends its name to the eponymous NGC 3783 galaxy group. Like galaxy clusters, galaxy groups are aggregates of gravitationally bound galaxies. Galaxy groups, however, are less massive and contain fewer members than galaxy clusters do: where galaxy clusters can contain hundreds or even thousands of constituent galaxies, galaxy groups do not typically include more than 50. The Milky Way is actually part of a galaxy group, known as the Local Group, which contains two other large galaxies (Andromeda and the Triangulum galaxy), as well as several dozen satellite and dwarf galaxies. The NGC 3783 galaxy group, meanwhile, contains 47 galaxies. It also seems to be at a fairly early stage of its evolution, making it an interesting object of study. Whilst the focus of this image is the spiral galaxy NGC 3783, …

8 April 2024: The subject of this week’s Picture of the Week from Hubble is the spiral galaxy IC 4633, located 100 million light-years away from us in the constellation Apus. IC 4633 is a galaxy rich in star-forming activity, as well as hosting an active galactic nucleus at its core. From our point of view, the galaxy is tilted mostly towards us, giving astronomers a fairly good view of its billions of stars. However, we can’t fully appreciate the features of this galaxy — at least in visible light — because it’s partially concealed by a stretch of dark dust. This dark nebula is part of the Chamaeleon star-forming region, itself located only around 500 light-years from us, in a nearby part of the Milky Way galaxy. The dark clouds in the Chamaeleon region occupy a large area of the southern sky, covering their namesake constellation but also encroaching on nearby constellations, …

1 April 2024: This image features Arp 72, a very selective galaxy group that only includes two interacting galaxies: NGC 5996 (the large spiral galaxy) and NGC 5994 (its smaller companion, in the lower left of the image). Both galaxies lie approximately 160 million light-years from Earth, and their cores are separated from each other by a distance of around 67 thousand light-years. Moreover, the distance between the galaxies at their closest points is even smaller, closer to 40 thousand light-years. Whilst this might still sound vast, in galactic separation terms it is really very cosy! For comparison, the distance between the Milky Way and its nearest independent galactic neighbour Andromeda is around 2.5 million light-years. Alternatively, the distance between the Milky Way and its largest and brightest satellite galaxy, the Large Magellanic Cloud (satellite galaxies are galaxies that are bound in orbit around another galaxy), is about 162 thousand light-years. Given this, …

25 March 2024: This image shows a globular cluster known as NGC 1651. Like the object in another recent Picture of the Week, it is located about 162 000 light-years away in the largest and brightest of the Milky Way’s satellite galaxies, the Large Magellanic Cloud (LMC). A notable feature of this image is that the globular cluster almost fills the entire image, even though globular clusters are only about 10 to 300 light-years in diameter (NGC 1651 has a diameter of roughly 120 light-years). In contrast, there are numerous Hubble Pictures of the Week that feature entire galaxies — which can be tens or hundreds of millions of light-years in diameter — that also more or less fill the whole image. A common misconception is that Hubble and other large telescopes manage to observe wildly differently sized celestial objects by zooming in on them, as one would with a specialised camera here …

18 March 2024: This gauzy-looking celestial body is UGC 5829, an irregular galaxy that lies about 30 million light-years away. Despite there not being many observations of this relatively faint galaxy, it has the distinction of having a descriptive soubriquet: the Spider Galaxy. Perhaps the distorted galactic arms with their glowing, star-forming tips bring to mind the clawed legs of an arachnid. Somewhat confusingly, there is another, very similarly nicknamed but otherwise entirely distinct, galaxy known as the Spiderweb Galaxy. This galaxy has also been more extensively imaged (notably by Hubble), despite the fact that it lies about 300 times further from Earth than the Spider Galaxy does. Fortunately, correct galaxy identification does not depend on casual given names. Rather, known galaxies are recorded in at least one catalogue — and often in several — such as the Uppsala General Catalogue of Galaxies, which gives the Spider Galaxy its more formal title of …

11 March 2024: This image shows LEDA 42160, a galaxy about 52 million light-years from Earth in the constellation Virgo. The dwarf galaxy is one of many forcing its way through the comparatively dense gas in the Virgo cluster, a massive cluster of galaxies. The pressure exerted by this intergalactic gas, known as ram pressure, has dramatic effects on star formation in LEDA 42160, which are presently being studied using the Hubble Space Telescope. LEDA 42160 falls into the category of ‘Magellanic spiral galaxy’, or type Sm for short, under the de Vaucouleurs galaxy classification system. Magellanic spiral galaxies can be further sub-categorised as barred (SBm), unbarred (SAm) and weakly barred (SABm), where a ‘bar’ is an elongated bar-shape at a galaxy’s core. Generally speaking, Magellanic spiral galaxies are dwarf galaxies with only one single spiral arm. They are named after their prototype, the Large Magellanic Cloud, which is an SBm galaxy. Magellanic …

4 March 2024: Here we see NGC 4423, a galaxy that lies about 55 million light-years away in the constellation Virgo. In this image NGC 4423 appears to have quite an irregular, tubular form, so it might be surprising to find out that it is in fact a spiral galaxy. Knowing this, we can make out the denser central bulge of the galaxy, and the less crowded surrounding disc (the part that comprises the spiral arms). If NGC 4423 were viewed face-on it would resemble the shape that we most associate with spiral galaxies: the spectacular curving arms sweeping out from a bright centre, interspersed with dimmer, darker, less populated regions. But when observing the skies we are constrained by the relative alignments between Earth and the objects that we are observing: we cannot simply reposition Earth so that we can get a better face-on view of NGC 4423! Of course, celestial objects …

26 February 2024: This densely populated group of stars is the globular cluster known as NGC 1841, which is found within the Large Magellanic Cloud (LMC), a satellite galaxy to the Milky Way galaxy that lies about 162 000 light-years away. Satellite galaxies are galaxies that are bound by gravity in orbits around a more massive host galaxy. We typically think of our galaxy’s nearest galactic companion as being the Andromeda Galaxy, but it would be more accurate to say that Andromeda is the nearest galaxy that is not in orbit around the Milky Way galaxy. In fact, our galaxy is orbited by tens of known satellite galaxies that are far closer than Andromeda, the largest and brightest of which is the LMC, which is easily visible to the naked eye from the southern hemisphere (although this is decreasingly the case thanks to light pollution). The LMC is home to many globular clusters. …

19 February 2024: This image features IC 3476, a dwarf galaxy that lies about 54 million light-years from Earth in the constellation Coma Berenices. Whilst this image does not look very dramatic — if we were to anthropomorphise the galaxy, we might say it looks almost serene — the actual physical events taking place in IC 3476 are highly energetic. In fact, the little galaxy is undergoing a process known as ram pressure stripping, which is driving unusually high levels of star formation within regions of the galaxy itself. We tend to associate the letters ‘ram’ with the acronym RAM, which refers to Random Access Memory in computing. However, ram pressure has a totally distinct definition in physics: it is the pressure exerted on a body when it moves through some form of fluid, due to the overall resistance of the fluid. In the case of entire galaxies experiencing ram pressure, the galaxies …

12 February 2024: If the Hubble Picture of the Week from two weeks ago was somewhat dim and subtle in appearance, then this week’s image is a veritable riot of colour and activity! It features a relatively close-by star-forming region known as IRAS 16562-3959 that lies within the Milky Way in the constellation Scorpius, about 5900 light-years from Earth. This image was compiled using observations from Hubble’s Wide Field Camera 3 (WFC 3). The detailed nuances of colour are possible because of the four separate filters that were used to collect the data. Filters are thin slivers of highly specialised material that only allow very specific wavelengths of light through. They can be slid in front of the part of the telescope that is sensitive to light, letting astronomers control which wavelengths of light the telescope collects with each observation. This is useful not only for specific scientific research, but also for the …

5 February 2024: This image shows a densely packed field of stars, laid on top of a background of dust, gas, and light from more distant celestial objects. The stars take up so much of the field of view in this image that it is a little tricky to discern that you are in fact looking at most of a galaxy, known as ESO 245-5. This galaxy is a relatively close neighbour of the Milky Way, lying at the fairly modest distance of 15 million light-years from Earth in the constellation Phoenix. Another reason that it is perhaps a little tricky to spot that ESO 245-5 is a galaxy is its apparent lack of structure. We frequently enjoy Hubble’s spectacular images of spiral galaxies, which are so interesting to look at in part because of their seemingly extraordinarily ordered arms of stars, gas and dust. ESO 245-5, in contrast, is classified as an …

29 January 2024: This image of the spiral galaxy UGC 11105 is not as bright and vivid as some other Hubble Pictures of the Week. This softly luminous galaxy — lying in the constellation Hercules, about 110 million light-years from Earth — seems outshone by the sparkling foreground stars that surround it. The type II supernova which took place in this galaxy in 2019, while no longer visible in this image, definitely outshone the galaxy at the time! To be more precise, UGC 11105 has an apparent magnitude of around 13.6 in the optical light regime (this image was created using data that covers the heart of the optical regime, in addition to ultraviolet data). Astronomers have different ways of quantifying how bright celestial objects are, and apparent magnitude is one of them. Firstly, the ‘apparent’ part of this quantity refers to the fact that apparent magnitude only describes how bright objects appear …

22 January 2024: This image shows the spiral galaxy IC 438, which lies about 130 million light-years from Earth in the constellation Lepus (the Hare). Lepus lies just south of the celestial equator (the ring around the middle of Earth that falls at right angles to its rotation axis). Appropriately, Lepus is flanked by the constellations Canis Major (the Greater Dog) and Orion (the Hunter), whilst Canis Minor (the Lesser Dog) lies very nearby, meaning that in artistic representations of the constellations, Lepus is often shown as being pursued by Orion and his two hunting dogs. Lepus is one of the 88 constellations that are officially recognised by the International Astronomical Union (IAU). It is worth clarifying that, whilst the actual constellations themselves only comprise a handful of stars, the area of sky covered by those stars is often referred to using the name of the constellation. For example, when we say that …

15 January 2024: This image features a relatively small galaxy known as UGC 5189A, which is located about 150 million light-years away in the constellation Leo. This galaxy was observed by Hubble to study a supernova explosion in 2010 known as SN 2010jl. This particular supernova was notable for having been an exceptionally luminous supernova event. In fact, over a period of three years, SN 2010jl released at least 2.5 billion times more visible energy alone than our Sun emitted over the same timeframe across all wavelengths. Even after supernovae have faded to non-observable levels, it can still be of interest to study the environments where they occurred. This can provide astronomers with valuable information: supernovae can take place for a variety of reasons, and understanding the environments in which they took place can help improve our understanding of the conditions necessary for them to be triggered. Furthermore, follow-up studies after supernovae can …

8 January 2024: This Hubble Picture of the Week features Arp 122, a peculiar galaxy that in fact comprises two galaxies — NGC 6040, the tilted, warped spiral galaxy and LEDA 59642, the round, face-on spiral — that are in the midst of a collision. This dramatic cosmic encounter is located at the very safe distance of roughly 570 million light-years from Earth. Peeking in at the corner is the elliptical galaxy NGC 6041, a central member of the galaxy cluster that Arp 122 resides in, but otherwise not participating in this monster merger. Galactic collisions and mergers are monumentally energetic and dramatic events, but they take place on a very slow timescale. For example, the Milky Way is on track to collide with its nearest galactic neighbour, the Andromeda Galaxy (M31), but these two galaxies have a good four billion years to go before they actually meet. The process of colliding and …

1 January 2024: What are we looking at when we study this image? A very distant galaxy that lies 19.5 billion light-years from Earth? Or a much closer luminous red galaxy that is a (relatively) small 2.7 billion light-years away? Or a third galaxy that appears to be fairly close to the second? The answer, perhaps confusingly, is that we are looking at all three. More precisely, we are looking at light emitted from all of those galaxies, even though the most distant galaxy lies directly behind the first as seen from Earth. In fact, it is that very alignment that makes the particular visuals in this image possible. The central bright dot in this image is one of the closer galaxies, known by the lengthy — but informative — name of SDSS J020941.27+001558.4 (galaxy names in this format provide precise information about their location in the sky). The other bright dot above …

25 December 2023: This Hubble Picture of the Week features a richness of spiral galaxies: the large, prominent spiral galaxy on the right side of the image is NGC 1356; the two apparently smaller spiral galaxies flanking it are LEDA 467699 (above it) and LEDA 95415 (very close at its left) respectively; and finally, IC 1947 sits along the left side of the image. ThIs image is a really interesting example of how challenging it can be to tell whether two galaxies are actually close together, or just seem to be from our perspective here on Earth. A quick glance at this image would likely lead you to think that NGC 1356, LEDA 467699 and LEDA 95415 were all close companions, whilst IC 1947 was more remote. However, we have to remember that two-dimensional images such as this one only give an indication of angular separation: that is, how objects are spread across …

18 December 2023: This whirling image features a bright spiral galaxy known as MCG-01-24-014, which is located about 275 million light-years from Earth. In addition to being a well-defined spiral galaxy, MCG-01-24-014 has an extremely energetic core, known as an active galactic nucleus (AGN), so it is referred to as an active galaxy. Even more specifically, it is categorised as a Type-2 Seyfert galaxy. Seyfert galaxies host one of the most common subclasses of AGN, alongside quasars. Whilst the precise categorisation of AGNs is nuanced, Seyfert galaxies tend to be relatively nearby ones where the host galaxy remains plainly detectable alongside its central AGN, while quasars are invariably very distant AGNs whose incredible luminosities outshine their host galaxies. There are further subclasses of both Seyfert galaxies and quasars. In the case of Seyfert galaxies, the predominant subcategories are Type-1 and Type-2. These are differentiated from one another by their spectra — the pattern …

11 December 2023: This image features an interacting galaxy system known as Arp-Madore 2105-332, that lies about 200 million light-years from Earth in the constellation Microscopium. Like other recent Hubble Pictures of the Week, this system belongs to the Arp-Madore catalogue of peculiar galaxies. The wonderful quality of this image also reveals several further galaxies, not associated with this system but fortuitously positioned in such a way that they appear to be forming a line that approaches the leftmost (in this image) component of Arp-Madore 2105-332, which is known individually as 2MASX J21080752-3314337. The rightmost galaxy, meanwhile, is known as 2MASX J21080362-3313196. These hefty names do not lend themselves to easy memorisation, but they do actually contain valuable information: they are coordinates in the right ascension and declination system used widely by astronomers to locate astronomical objects. Both the galaxies are of a type known as emission-line galaxies. This simply means that, when …

4 December 2023: This striking image shows the densely packed globular cluster known as NGC 2210, which is situated in the Large Magellanic Cloud (LMC). The LMC lies about 157 000 light-years from Earth, and is a so-called satellite galaxy of the Milky Way, meaning that the two galaxies are gravitationally bound. Globular clusters are very stable, tightly bound clusters of thousands or even millions of stars. Their stability means that they can last a long time, and therefore globular clusters are often studied in order to investigate potentially very old stellar populations. In fact, 2017 research that made use of some of the data that were also used to build this image revealed that a sample of LMC globular clusters were incredibly close in age to some of the oldest stellar clusters found in the Milky Way’s halo. They found that NGC 2210 specifically probably clocks in at around 11.6 billion years …

27 November 2023: This Hubble Picture of the Week features a massive cluster of brightly glowing galaxies, first identified as Abell 3192. Like all galaxy clusters, this one is suffused with hot gas that emits powerful X-rays, and it is enveloped in a halo of invisible dark matter. All this unseen material — not to mention the many galaxies visible in this image — comprises such a huge amount of mass that the galaxy cluster noticeably curves spacetime around it, making it into a gravitational lens. Smaller galaxies behind the cluster appear distorted into long, warped arcs around the cluster’s edges. The galaxy cluster is located in the constellation Eridanus, but the question of its distance from Earth is a more complicated one. Abell 3192 was originally documented in the 1989 update of the Abell catalogue, a catalogue of galaxy clusters that was first published in 1958. At that time, Abell 3192 was …

20 November 2023: This Hubble Picture of the Week features NGC 2814, an irregular galaxy that lies about 85 million light years from Earth. In this image, which was captured using Hubble’s Advanced Camera for Surveys (ACS), the galaxy appears to be quite isolated: visually, it looks a little like a loose stroke of bright paint across a dark background. However, looks can be deceiving. NGC 2814 actually has three close (in astronomical terms) galactic neighbours: a side-on spiral galaxy known as NGC 2820; an irregular galaxy named IC 2458; and a face-on non-barred spiral galaxy called NGC 2805. Collectively, the four galaxies make up a galaxy group known as Holmberg 124. In some literature these galaxies are referred to as a group of ‘late-type galaxies’. The terminology ‘late-type’ refers to spiral and irregular galaxies, whilst ‘early-type’ refers to elliptical galaxies. This rather confusing terminology has led to a common misconception within the …

13 November 2023: This luminous tangle of stars and dust is the barred spiral galaxy NGC 1385, that lies about 30 million light-years from Earth. The same galaxy was the subject of another Hubble Picture of the Week, but the two images are notably different. This more recent image has far more pinkish-red and umber shades, whereas the former image was dominated by cool blues. This chromatic variation is not just a creative choice, but also a technical one, made in order to represent the different number and type of filters used to collect the data that were used to make the respective images. It is understandable to be a bit confused as to how the same galaxy, imaged twice by the same telescope, could be represented so differently in two different images. The reason is that — like all powerful telescopes used by professional astronomers for scientific research — Hubble is equipped …

6 November 2023: This image features the spiral galaxy NGC 941, which lies about 55 million light-years from Earth. The data used for this image were collected by Hubble’s Advanced Camera for Surveys (ACS). The beautiful NGC 941 is undoubtedly the main attraction in this image; however, this hazy-looking galaxy was not the motivation for the data being collected. That distinction belongs to an astronomical event that took place in the galaxy years before: the supernova SN 2005ad. The location of this faded supernova was observed as part of a study of multiple hydrogen-rich supernovae, also known as type II supernovae, in order to better understand the environments in which certain types of supernovae take place. Whilst the study was conducted by professional astronomers, SN 2005ad itself owes its discovery to a distinguished amateur astronomer named Kōichi Itagaki, who has discovered over 170 supernovae. This might raise the question of how an amateur …

30 October 2023: This vibrant and dynamic-looking image features the spiral galaxy NGC 1566, which is sometimes informally referred to as the ‘Spanish Dancer Galaxy’. Like the subject of another recent Hubble Picture of the Week, NGC 1566 is a weakly-barred or intermediate spiral galaxy, meaning that it does not have either a clearly present or a clearly absent bar-shaped structure at its centre. The galaxy owes its nickname to the vivid and dramatic swirling lines of its spiral arms, which could evoke the shapes and colours of a dancer’s moving form. NGC 1566 lies around 60 million light-years from Earth in the constellation Dorado, and is also a member of the Dorado galaxy group. Galaxy groups are assemblages of gravitationally bound galaxies. Groups differ from galaxy clusters in size and mass: galaxy clusters may contain hundreds of galaxies, whereas groups might contain several tens of galaxies. That said, there is not a …

23 October 2023: This striking image captures the interacting galaxy pair known as Arp-Madore 2339-661, so named because they belong to the Arp-Madore catalogue of peculiar galaxies. However, this particular peculiarity might be even odder than first meets the eye, as there are in fact three galaxies interacting here, not just two. The two clearly defined galaxies are NGC 7733 (smaller, lower right) and NGC 7734 (larger, upper left). The third galaxy is currently referred to as NGC 7733N, and can actually be spotted in this picture if you look carefully at the upper arm of NGC 7733, where there is a visually notable knot-like structure, glowing with a different colour to the arm and obscured by dark dust. This could easily pass as part of NGC 7733, but analysis of the velocities (speed, but also considering direction) involved in the galaxy shows that this knot has a considerable additional redshift, meaning that …

16 October 2023: This glittering image shows the spiral galaxy IC 5332, which lies about 30 million light-years away in the constellation Sculptor, and has an almost face-on orientation to Earth. To explain what is meant by ‘face-on’, it is helpful to visualise a spiral galaxy as an (extremely) large disc. If the galaxy is oriented so that it appears circular and disc-shaped from our perspective here on Earth, then we can say that it is ‘face-on’. In contrast, if it is oriented so that it appears squashed and oval-shaped, then we would say that it is ‘edge-on’. The key thing is that the same galaxy would look extremely different from our perspective depending on whether it was face-on or edge-on as seen from Earth. Check out these previous Hubble Pictures of the Week for examples of another face-on spiral galaxy and an almost edge-on spiral galaxy. IC 5332 is designated as an …

9 October 2023: This Picture of the Week prominently features two galaxies: NGC 3558 in the lower left, and LEDA 83465 in the upper right. Both galaxies lie roughly 450 million light years from Earth. The two galaxies are separated from one another by a distance of roughly 150 000 light years, which might sound vast, until we consider that our nearest galactic neighbour — the Andromeda galaxy — is a whopping 2.5 million light years distant from the Milky Way galaxy. In galactic terms, the two galaxies pictured here are practically on top of one another. This is because they belong to a crowded and chaotic galaxy cluster known as Abell 1185, which is packed with galaxies that are interacting with one another via gravity. These galactic interactions have sometimes led to dramatic results, such as galaxies being torn apart completely. This fate has not befallen NGC 3558, which currently retains its …

2 October 2023: This spectacular image shows a region called G35.2-0.7N, which is known as a hotbed of high-mass star formation. The kind of stars that form here are so massive that they will end their lives as destructive supernovae. However, even as they form they greatly impact their surroundings. At least one B-type star — the second most massive type — lurks within the region pictured here, and a powerful protostellar jet that it is launching towards us is the source of the spectacular light show. The image was taken with the Wide Field Camera 3 (WFC3), which is mounted on the NASA/ESA Hubble Space Telescope, and the region G35.2-0.7N lies around 7200 light-years from Earth in the constellation Aquila. This beautiful picture was assembled using data that were collected primarily for very specific research purposes, as are many of the Hubble Pictures of the Week. The research conducted using these data …

25 September 2023: This Hubble Picture of the Week includes the pithily-named galaxy SDSS J103512.07+461412.2, visible in the centre of this image as a dispersed sweep of dust and stars with a denser, brighter core. SDSS J103512.07+461412.2 is located 23 million light-years from Earth in the constellation Ursa Major. The seemingly rambling name is because this galaxy was observed as part of the Sloan Digital Sky Survey (SDSS), a massive survey that began in 2000 with the aim of observing and cataloguing vast numbers of astronomical objects. So far, it has recorded several hundred million astronomical objects. In the early days of astronomy catalogues, astronomers painstakingly recorded individual objects one by one. As an example, the Messier catalogue includes only 110 objects, identified by the astronomer Charles Messier because they were all getting in the way of his comet-hunting efforts. As the Messier catalogue is so limited, it is sufficient to simply refer …

18 September 2023: This Hubble Picture of the Week — taken using the NASA/ESA Hubble Space Telescope’s Advanced Camera for Surveys (ACS) — shows Arp 107, a celestial object that comprises a pair of galaxies in the midst of a collision. The larger galaxy (on the left of this image) is an extremely energetic galaxy of a type known as a Seyfert galaxy, which house active galactic nuclei at their cores. Seyfert galaxies are notable because, despite the immense brightness of the active core, radiation from the entire galaxy can be observed. This is evident in this image, where the spiraling whorls of the whole galaxy are readily visible. The smaller companion is connected to the larger by a seemingly tenuous ‘bridge’, composed of dust and gas. The colliding galactic duo lies about 465 million light-years from Earth. Arp 107 is included in a catalogue of 338 galaxies known as the Atlas of …

11 September 2023: This dream-like Picture of the Week features the galaxy known as NGC 3156. It is a lenticular galaxy, meaning that it falls somewhere between an elliptical and a spiral galaxy. It lies about 73 million light-years from Earth, in the minor equatorial constellation Sextans. Sextans is a small constellation that belongs to the Hercules family of constellations. It itself is a constellation with an astronomical theme, being named for the instrument known as the sextant. Sextants are often thought of as navigational instruments that were invented in the 18th century. However, the sextant as an astronomical tool has been around for much longer than that: Islamic scholars developed astronomical sextants many hundreds of years earlier in order to measure angles in the sky. A particularly striking example is the enormous sextant with a radius of 36 metres that was developed by Ulugh Beg of the Timurid dynasty in the fifteenth …

4 September 2023: The swirls of the galaxy IC 1776 stand in splendid isolation in this image from the NASA/ESA Hubble Space Telescope. This galaxy lies over 150 million light-years from Earth in the constellation Pisces. IC 1776 recently played host to a catastrophically violent explosion — a supernova — which was discovered in 2015 by the Lick Observatory Supernova Search, a robotic telescope which scours the night sky in search of transient phenomena such as supernovae. A network of automatic robotic telescopes are spread across the globe, operated by both professional and amateur astronomers, and, without human intervention, reveal short-lived astronomical phenomena such as wandering asteroids, gravitational microlensing, or supernovae. Hubble investigated the aftermath of the supernova SN 2015ap during two different observing programmes, both designed to comb through the debris left by supernovae explosions in order to better understand these energetic events. A variety of telescopes automatically follow up the detection …

28 August 2023: The protostellar object OH 339.88-1.26, which lies 8 900 light-years from Earth in the constellation Ara, lurks in this dust-filled image from the NASA/ESA Hubble Space Telescope. Winding lanes of dark dust thread through this image, which is also studded with bright stars crowned with criss-crossing diffraction spikes. The dark vertical streak at the centre of this image hides OH 339.88-1.26, which is an astrophysical maser. A maser — which is an acronym for “microwave amplification by stimulated emission of radiation” — is essentially a laser that produces coherent light at microwave wavelengths. Such objects can occur naturally in astrophysical situations, in environments ranging from the north pole of Jupiter to star-forming regions such as the one pictured here. This image comes from a set of Hubble observations that peer into the hearts of regions where massive stars are born to constrain the nature of massive protostars and test theories …

21 August 2023: The galaxy ESO 300-16 looms over this image from the NASA/ESA Hubble Space Telescope. This galaxy, which lies 28.7 million light-years from Earth in the constellation Eridanus, is a ghostly assemblage of stars which resembles a sparkling cloud. A rogue’s gallery of distant galaxies and foreground stars complete this astronomical portrait, which was captured by the Advanced Camera for Surveys. This observation is one of a series which aims to get to know our galactic neighbours; around three quarters of the known galaxies suspected to lie within 10 megaparsecs of Earth have been observed by Hubble in enough detail to resolve their brightest stars and establish the distances to these galaxies. A team of astronomers proposed using small gaps in Hubble’s observing schedule to acquaint ourselves with the remaining quarter of the nearby galaxies. The megaparsec — meaning one million parsecs — is a unit used by astronomers to chart …

14 August 2023: The massive cluster Abell 3322 is featured in this image from the NASA/ESA Hubble Space Telescope, in which the galaxy 2MASX J05101744-4519179 basks in the centre. This distant galaxy cluster is a cosmic leviathan that is highly luminous at X-ray wavelengths. Observing galaxy clusters like Abell 3322 can advance our understanding of the evolution and interactions of dark and luminous matter in galaxy clusters, and also reveals powerful gravitational ‘telescopes’ that magnify distant objects through gravitational lensing. Knowing the location of these lenses can enable future observations with both Hubble and the NASA/ESA/CSA James Webb Space Telescope. The galaxy cluster is located in the constellation Pictor, around 2.6 billion light-years from Earth. The unusual alignment of the three brightest cluster galaxies in this image (two in a close pair in the centre of the image and a third in the upper right region) suggests that A3322 is observed in the …

7 August 2023: The lenticular galaxy NGC 6684 bathes this image from the NASA/ESA Hubble Space Telescope in a pale light. Captured with Hubble’s Advanced Camera for Surveys, this lenticular galaxy is around 44 million light-years from Earth in the constellation Pavo. Pavo — whose name is Latin for peacock — is a constellation in the southern sky and one of four constellations collectively known as the Southern Birds. Lenticular galaxies like NGC 6684 (lenticular means lens-shaped) possess a large disc but lack the prominent spiral arms of galaxies like the Andromeda Galaxy. This leaves them somewhere between elliptical galaxies and spiral galaxies, and lends these galaxies a diffuse, ghostly experience. NGC 6684 also lacks the dark dust lanes that thread through other galaxies, adding to its spectral, insubstantial appearance. The data in this image were captured during a census of the nearby Universe entitled Every Known Nearby Galaxy which aims to observe …

31 July 2023: The glittering, glitzy contents of the globular cluster NGC 6652 sparkle in this star-studded image from the NASA/ESA Hubble Space Telescope. The core of the cluster is suffused with the pale blue light of countless stars, and a handful of particularly bright foreground stars are adorned with criss-crossing diffraction spikes. NGC 6652 lies in our own Milky Way galaxy in the constellation Sagittarius, just under 30 000 light-years from Earth and only 6500 light-years from the Galactic centre. Globular clusters are stable, tightly gravitationally bound clusters containing anywhere between tens of thousands and millions of stars. The intense gravitational attraction between the closely packed stars in globular clusters is what gives these star-studded objects their regular, spherical shape. This image combines data from two of Hubble’s third-generation instruments; the Advanced Camera for Surveys and Wide Field Camera 3. As well as two instruments, this image draws on two different observing …

24 July 2023: The tranquil spiral galaxy UGC 12295 basks leisurely in this image from the NASA/ESA Hubble Space Telescope. This galaxy lies around 192 million light-years away in the constellation Pisces, and is almost face-on when viewed from Earth, displaying a bright central bar and tightly wound spiral arms. Despite appearing as an island of tranquillity in this image, UGC 12295 played host to a catastrophically violent explosion — a supernova — that was first detected in 2015. This supernova prompted two different teams of astronomers to propose Hubble observations of UGC 12295 that would sift through the wreckage of this vast stellar explosion. Supernovae are the explosive deaths of massive stars, and are responsible for forging many of the elements found here on Earth. The first team of astronomers used Hubble’s Wide Field Camera 3 (WFC3) to examine the detritus left behind by the supernova in order to better understand the …

17 July 2023: The irregular galaxy Arp 263 lurks in the background of this image from the NASA/ESA Hubble Space Telescope, but the view is dominated by a stellar photobomber; the bright star BD+17 2217. Arp 263 — also known as NGC 3239 — is a patchy, irregular galaxy studded with regions of recent star formation, and astronomers believe that its ragged appearance is due to its having formed from the merger of two galaxies. It lies around 25 million light-years away in the constellation Leo. Two different Hubble investigations into Arp 263, using two of Hubble’s third-generation instruments, contributed data to this image. The first investigation was part of an effort to observe the sites of recent supernovae, such as the supernova SN 2012A that was detected just over a decade ago in Arp 263. Astronomers used Hubble’s powerful Wide Field Camera 3 to search for lingering remnants of the colossal stellar …

10 July 2023: The NASA/ESA Hubble Space Telescope has captured a monster in the making in this observation of the exceptional galaxy cluster eMACS J1353.7+4329, which lies about eight billion light-years from Earth in the constellation Canes Venatici. This disturbed collection of at least two galaxy clusters is in the process of merging together to create a cosmic monster, a single gargantuan cluster acting as a gravitational lens. Gravitational lensing is a dramatic example of Einstein’s general theory of relativity in action. A celestial body such as a galaxy cluster is sufficiently massive to distort spacetime, which causes the path of light around the object to be visibly bent as if by a vast lens. Gravitational lensing can also magnify distant objects, allowing astronomers to observe objects that would otherwise be too faint and too far away to be detected. It can also distort the images of background galaxies, turning them into streaks …