Picture of the Week

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 …

3 July 2023: The spiral galaxy UGC 11860 seems to float serenely against a field of background galaxies in this image from the NASA/ESA Hubble Space Telescope. UGC 11860 lies around 184 million light-years away in the constellation Pegasus, and its untroubled appearance is deceiving; this galaxy recently played host to an almost unimaginably energetic stellar explosion. A supernova explosion — the catastrophically violent end of a massive star’s life — was detected in UGC 11860 in 2014 by a robotic telescope dedicated to scouring the skies for transient astronomical phenomena — astronomical objects that are only visible for a short period of time. Two different teams of astronomers used Hubble’s Wide Field Camera 3 to search through the aftermath and unpick the lingering remnants of this vast cosmic explosion. One team explored UGC 11860 to understand more about the progenitor star systems that eventually meet their demise in supernovae. The hugely energetic …

13 December 2021: In this image, the NASA/ESA Hubble Space Telescope captures a side-on view of NGC 3568, a barred spiral galaxy roughly 57 million light-years from the Milky Way in the constellation Centaurus. In 2014 the light from a supernova explosion in NGC 3568 reached Earth — a sudden flare of light caused by the titanic explosion accompanying the death of a massive star. Whilst most astronomical discoveries are the work of teams of professional astronomers, this supernova was discovered by amateur astronomers from the Backyard Observatory Supernova Search in New Zealand. Dedicated amateur astronomers often make intriguing discoveries — particularly of fleeting astronomical phenomena such as supernovae. This Hubble observation comes from a hoard of data built up to pave the way for future science with the upcoming NASA/ESA/CSA James Webb Space Telescope. By combining ground-based observations with data from Hubble’s Advanced Camera for Surveys and Wide Field Camera 3, astronomers …

11 October 2021: NGC 4666 takes centre stage in this image from the NASA/ESA Hubble Space Telescope. This majestic spiral galaxy lies about 80 million light-years away in the constellation Virgo, and is undergoing a particularly intense episode of star formation. Astronomers refer to galaxies which are forming stars anomalously quickly as starburst galaxies. NGC 4666’s starburst is thought to be due to gravitational interactions with its unruly neighbours — including the nearby galaxy NGC 4668 and a dwarf galaxy. NGC 4666’s burst of star formation is driving an unusual form of extreme galactic weather known as a superwind — a gigantic transfer of gas from the bright central heart of the galaxy out into space. This superwind is the result of driving winds from short-lived massive stars formed during NGC 4666’s starburst as well as spectacularly energetic supernova explosions. Two such supernova explosions have been seen in NGC 4666 within the last …

9 August 2021: Clustered at the centre of this image are six luminous spots of light, four of them forming a circle around a central pair. Appearances can be deceiving, however, as this formation is not composed of six individual galaxies, but only three: to be precise, a pair of galaxies and one distant quasar. Hubble data also indicates that there is a seventh spot of light in the very center, which is a rare fifth image of the distant quasar. This rare phenomenon is caused by the presence of two galaxies in the foreground that act as a lens. These galaxies were imaged in spectacular detail by Hubble’s Wide Field Camera 3 (WFC3), which was installed on Hubble in 2009 during Hubble Servicing Mission 4, Hubble’s final servicing mission. The WFC3 was intended to operate until 2014, but 12 years after it was installed it continues to provide both top-quality data and …

6 April 2020: At first glance, the subject of this NASA/ESA Hubble Space Telescope image looks to be a simple spiral galaxy, with two pinwheeling arms emerging from a central bar of stars and material that cuts through the galactic centre. In fact, there are rings within these spiral arms, too: spirals within a spiral. This kind of morphology is known as a multiring structure. As this description suggests, this galaxy, named NGC 2273, hosts an inner ring and two outer “pseudorings” — having so many distinct rings is rare, and makes NGC 2273 unusual. Rings are created when a galaxy’s spiral arms appear to loop around to nearly close upon one another, combined with a trick of cosmic perspective. NGC 2273’s two pseudorings are formed by two swirling sets of spiral arms coming together, and the inner ring by two arcing structures nearer to the galactic centre, which seem to connect in …

18 February 2019: Since Pluto’s status-change from fully-fledged planet to dwarf planet, Neptune holds the title of outermost planet in the Solar System. This new image of the planet was made during Hubble’s Outer Planet Atmosphere Legacy (OPAL) programme, under which it has observed the four outermost planets, including Neptune, on a yearly basis since 2014. The observations of Neptune carried out in September and November 2018 show the first evidence of a huge storm brewing, with the discovery of a new northern Great Dark Spot (visible here to the upper left of the planet’s disc, partially overlapping a large patch of white). This new dark storm is of a similar size and shape to the storm discovered in 1989 by the Voyager 2 space probe. While the future evolution of the storm will be tracked through the continued yearly Hubble observations and also by ground-based telescopes, older OPAL observations from Hubble show …

27 August 2018: Following on from last week’s Picture of the Week, this week we showcase the second part of the Hubble Deep UV (HDUV) Legacy Field, the GOODS-South view. With the addition of new ultraviolet light imagery, astronomers using the NASA/ESA Hubble Space Telescope have captured the largest panoramic view of the fire and fury of star birth in the distant Universe, encompassing 12 000 star-forming galaxies. Hubble’s ultraviolet vision opens up a new window on the evolving Universe, tracking the birth of stars over the last 11 billion years up to the cosmos’s busiest star-forming period, which happened about three billion years after the Big Bang. So far, ultraviolet light has been the missing piece of the cosmic puzzle. Now, combined with data in infrared, and visible light from Hubble and other space- and ground-based telescopes, astronomers have assembled the most comprehensive portrait yet of the Universe’s evolutionary history. The image …

20 August 2018: The Hubble Deep Field from 1995 allowed astronomers a first glimpse into the early Universe. This first picture was followed later by an even deeper observation, the Hubble Ultra Deep Field in 2004. Both images were observed in visible light, the same form of light human eyes can see. But astronomers are also interested in the many forms of invisible light out in the Universe. Therefore, the Ultra Deep Field was later observed in the infrared and the ultraviolet as well, allowing scientists to learn even more about the Universe and to look back even further into its history. It is less known that the famous deep field observations were not the only images the NASA/ESA Hubble Space Telescope took of the distant Universe. Hubble is also an essential part of the GOODS (The Great Observatories Origins Deep Survey) programme, which unites extremely deep observations from several space telescopes: NASA’s …

29 January 2018: This NASA/ESA Hubble Space Telescope image shows a spiral galaxy known as NGC 7331. First spotted by the prolific galaxy hunter William Herschel in 1784, NGC 7331 is located about 45 million light-years away in the constellation of Pegasus (The Winged Horse). Facing us partially edge-on, the galaxy showcases it’s beautiful arms which swirl like a whirlpool around its bright central region. Astronomers took this image using Hubble’s Wide Field Camera 3 (WFC3), as they were observing an extraordinary exploding star — a supernova — which can still be faintly seen as a tiny red dot near the galaxy’s central yellow core. Named SN2014C, it rapidly evolved from a supernova containing very little Hydrogen to one that is Hydrogen-rich — in just one year. This rarely observed metamorphosis was luminous at high energies and provides unique insight into the poorly understood final phases of massive stars. NGC 7331 is similar …

8 January 2018: In 2014, astronomers using the NASA/ESA Hubble Space Telescope found that this enormous galaxy cluster contains the mass of a staggering three million billion Suns — so it’s little wonder that it has earned the nickname of “El Gordo” (“the Fat One” in Spanish)! Known officially as ACT-CLJ0102-4915, it is the largest, hottest, and X-ray brightest galaxy cluster ever discovered in the distant Universe. Galaxy clusters are the largest objects in the Universe that are bound together by gravity. They form over billions of years as smaller groups of galaxies slowly come together. In 2012, observations from ESO’s Very Large Telescope, NASA’s Chandra X-ray Observatory and the Atacama Cosmology Telescope showed that El Gordo is actually composed of two galaxy clusters colliding at millions of kilometres per hour. The formation of galaxy clusters depends heavily on dark matter and dark energy; studying such clusters can therefore help shed light on …

19 June 2017: The object in the middle of this image, sitting alone within a star-studded cosmos, is a galaxy known as ESO 486-21. ESO 486-21 is a spiral galaxy — albeit with a somewhat irregular and ill-defined structure — located some 30 million light-years from Earth. The NASA/ESA Hubble Space Telescope observed this object while performing a survey — the Legacy ExtraGalactic UV Survey (LEGUS) — of 50 nearby star-forming galaxies. The LEGUS sample was selected to cover a diverse range of galactic morphologies, star formation rates, galaxy masses, and more. Astronomers use such data to understand how stars form and evolve within clusters, and how these processes affect both their home galaxy and the wider Universe. ESO 486-21 is an ideal candidate for inclusion in such a survey as it is known to be in the process of forming new stars, which are created when large clouds of gas and dust …

22 May 2017: The NASA/ESA Hubble Space Telescope still has a few tricks up its sleeve in its task of exploring the Universe. For one, it is able to image two adjacent parts of the sky simultaneously. It does this using two different cameras — one camera can be trained on the target object itself, and the other on a nearby patch of sky so that new and potentially interesting regions of the cosmos can be observed at the same time (these latter observations are known as parallel fields). This image shows part of a bubble-like cloud of gas — a nebula named Sh2-308 — surrounding a massive and violent star named EZ Canis Majoris. It uses observations from Hubble’s Advanced Camera for Surveys, and is the parallel field associated with another view of the nebula produced by Hubble’s Wide Field Camera 3. EZ Canis Majoris is something known as a Wolf-Rayet star, …

3 April 2017: Ever since Voyager 2 beamed home spectacular images of the planets in the 1980s, planet-lovers have been hooked on extra-terrestrial aurorae. Aurorae are caused by streams of charged particles like electrons, that come from various origins such as solar winds, the planetary ionosphere, and moon volcanism. They become caught in powerful magnetic fields and are channelled into the upper atmosphere, where their interactions with gas particles, such as oxygen or nitrogen, set off spectacular bursts of light. The alien aurorae on Jupiter and Saturn are well-studied, but not much is known about the aurorae of the giant ice planet Uranus. In 2011, the NASA/ESA Hubble Space Telescope became the first Earth-based telescope to snap an image of the aurorae on Uranus. In 2012 and 2014 a team led by an astronomer from Paris Observatory took a second look at the aurorae using the ultraviolet capabilities of the Space Telescope Imaging …

23 May 2016: Nearly as deep as the Hubble Ultra Deep Field, which contains approximately 10 000 galaxies, this incredible image from the NASA/ESA Space Telescope reveals thousands of colourful galaxies in the constellation of Leo (The Lion). This vibrant view of the early Universe was captured as part of the Frontier Fields campaign, which aims to investigate galaxy clusters in more detail than ever before, and to explore some of the most distant galaxies in the Universe. Galaxy clusters are massive. They can have a tremendous impact on their surroundings, with their immense gravity warping and amplifying the light from more distant objects. This phenomenon, known as gravitational lensing, can help astronomers to see galaxies that would otherwise be too faint, aiding our hunt for residents of the primordial Universe. MACS J1149.5+2223 is a galaxy cluster located approximately five billion light-years away. In 2012, it helped astronomers uncover one of the most …

7 March 2016: Peering deep into the early Universe, this picturesque parallel field observation from the NASA/ESA Hubble Space Telescope reveals thousands of colourful galaxies swimming in the inky blackness of space. A few foreground stars from our own galaxy, the Milky Way, are also visible. In October 2013 Hubble’s Wide Field Camera 3 (WFC3) and Advanced Camera for Surveys (ACS) began observing this portion of sky as part of the Frontier Fields programme. This spectacular skyscape was captured during the study of the giant galaxy cluster Abell 2744, otherwise known as Pandora’s Box. While one of Hubble’s cameras concentrated on Abell 2744, the other camera viewed this adjacent patch of sky near to the cluster. Containing countless galaxies of various ages, shapes and sizes, this parallel field observation is nearly as deep as the Hubble Ultra-Deep Field. In addition to showcasing the stunning beauty of the deep Universe in incredible detail, this …

3 March 2014: Spiral galaxy Messier 82 has long been known for its remarkable starburst activity, caused by interactions with its near neighbour Messier 81, and has been the subject of intense study for many years. On 21 January 2014, astronomers at the University of London Observatory in London, UK, pointed their telescope at the galaxy and spied something peculiar… an intensely bright spot seemed to have suddenly appeared within the galaxy [1]. This bright spot is actually a new supernova known as SN 2014J — the closest supernova to Earth in recent decades! Since its discovery, SN 2014J has been confirmed as a type Ia supernova, making it the closest of its type to Earth in over 40 years (since SN 1972E) [2]. This new NASA/ESA Hubble Space Telescope image is set against a previous mosaic of Messier 82 from 2006 (heic0604a), and shows the supernova as an intensely bright spot towards …