Picture of the Week

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 …

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 …

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 …

10 October 2022: Terzan 1 is a globular cluster that lies about 22,000 light-years from Earth in the constellation Scorpius. It is one of 11 globular clusters that were discovered by the Turkish-Armenian astronomer Agop Terzan between 1966 and 1971 when he was working in France, based mostly at Lyon Observatory. Somewhat confusingly, the 11 Terzan globular clusters are numbered from Terzan 1 to Terzan 12. This is due to an error made by Terzan in 1971, when he rediscovered Terzan 5 — a cluster he had already discovered and reported back in 1968 — and named it Terzan 11. He published its discovery alongside those of Terzan 9, 10 and 12. He quickly realised his mistake, and attempted to have Terzan 12 renamed as Terzan 11. Unfortunately, he did not make it clear that Terzan 5 and Terzan 11 were one and the same, although another astronomer, Ivan Robert King, did publish …

7 March 2022: An energetic outburst from an infant star streaks across this image from the NASA/ESA Hubble Space Telescope. This stellar tantrum — produced by an extremely young star in the earliest phase of formation — consists of an incandescent jet of gas travelling at supersonic speeds. As the jet collides with material surrounding the still-forming star, the shock heats this material and causes it to glow. The result is the colourfully wispy structures, which astronomers refer to as Herbig–Haro objects, billowing across the lower left of this image. Herbig–Haro objects are seen to evolve and change significantly over just a few years. This particular object, called HH34, was previously captured by Hubble between 1994 and 2007, and again in glorious detail in 2015. HH34 resides approximately 1250 light-years from Earth in the Orion Nebula, a large region of star formation visible to the unaided eye. The Orion Nebula is one of …

17 August 2020: This image from the NASA/ESA Hubble Space Telescope features the spectacular galaxy NGC 2442. This galaxy was host to a supernova explosion, known as SN2015F, that was created by a white dwarf star. The white dwarf was part of a binary star system and syphoned mass from its companion, eventually becoming too greedy and taking on more than it could handle. This unbalanced the star and triggered runaway nuclear fusion that eventually led to an intensely violent supernova explosion. SN2015F was spotted in March 2015 in the galaxy named NGC 2442, nicknamed the Meathook Galaxy owing to its extremely asymmetrical and irregular shape. The supernova shone brightly for quite some time and was easily visible from Earth through even a small telescope until later that summer.

15 June 2020: Seen here in incredible detail, thanks to the NASA/ESA Hubble Space Telescope, is the starburst galaxy formally known as PLCK G045.1+61.1. The galaxy appears as multiple reddish dots near the center of the image and is being gravitationally lensed by a cluster of closer galaxies that are also visible in this image. Gravitational lensing occurs when a large distribution of matter, such as a galaxy cluster, sits between Earth and a distant light source. As space is warped by massive objects, the light from the distant object bends as it travels to us. This effect was first predicted by Einstein’s general theory of relativity. From 2009 to 2013, the European Space Agency’s Planck space observatory captured multiple all-sky surveys. In the course of these surveys, with complementary observations by the Herschel Space Observatory, Planck discovered some of the brightest gravitationally lensed high-redshift galaxies in the night sky. It was …

4 May 2020: In the forests of the night lies a barred spiral galaxy called NGC 3583, imaged here by the NASA/ESA Hubble Space Telescope. This is a barred spiral galaxy with two arms that twist out into the Universe. This galaxy is located 98 million light-years away from the Milky Way. Two supernovae exploded in this galaxy, one in 1975 and another, more recently, in 2015. There are a few different ways that supernova can form. In the case of these two supernovae, the explosions evolved from two independent binary star systems in which the stellar remnant of a Sun-like star, known as a white dwarf, was collecting material from its companion star. Feeding off of its partner, the white dwarf gorged on the material until it reached a maximum mass. At this point, the star collapsed inward before exploding outward in a brilliant supernova. Two of these events were spotted in …

13 April 2020: This image depicts a swirling spiral galaxy named NGC 2906. The blue speckles seen scattered across this galaxy are massive young stars, which emit hot, blue-tinged radiation as they burn through their fuel at an immense rate. The swathes of orange are a mix of older stars that have swollen and cooled, and low-mass stars that were never especially hot to begin with. Owing to their lower temperatures, these stars emit a cooler, reddish, radiation. This image of NGC 2906 was captured by the NASA/ESA Hubble Space Telescope’s Wide Field Camera 3, an instrument installed on Hubble in 2009 during the telescope’s fourth servicing mission. Hubble observed this galaxy on the hunt for fading light from recent, nearby occurrences of objects known as supernovae.

6 January 2020: This Picture of the Week, taken by the NASA/ESA Hubble Space Telescope, shows a close-up view of a galaxy named NGC 2770. NGC 2770 is intriguing, as over time it has hosted four different observed supernovae (not visible here). Supernovae form in a few different ways, but always involve a dying star. These stars become unbalanced, lose control, and explode violently, briefly shining as brightly as an entire galaxy before slowly fading away. One of the four supernovae observed within this galaxy, SN 2015bh, is especially interesting. This particular supernova initially had its identity called into question. When it was first discovered in 2015, astronomers classified SN 2015bh as a supernova imposter, believing it to be not an exploding star but simply an unpredictable outburst from a massive star in its final phase of life. Thankfully, astronomers eventually discovered the truth and the object was given its correct classification as …

4 March 2019: Located in the constellation of Hercules, about 230 million light-years away, NGC 6052 is a pair of colliding galaxies. They were first discovered in 1784 by William Herschel and were originally classified as a single irregular galaxy because of their odd shape. However, we now know that NGC 6052 actually consists of two galaxies that are in the process of colliding. This particular image of NGC 6052 was taken using the Wide Field Camera 3 on the NASA/ESA Hubble Space Telescope. A long time ago gravity drew the two galaxies together into the chaotic state we now observe. Stars from within both of the original galaxies now follow new trajectories caused by the new gravitational effects. However, actual collisions between stars themselves are very rare as stars are very small relative to the distances between them (most of a galaxy is empty space). Eventually things will settle down and one …

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 …

5 March 2018: This enchanting spiral galaxy can be found in the constellation of Ursa Major (the Great Bear). Star-studded NGC 3972 lies about 65 million light-years away from the Earth, meaning that the light that we see now left it 65 million years ago, just when the dinosaurs became extinct. NGC 3972 has had its fair share of dramatic events. In 2011 astronomers observed the explosion of a type Ia supernova in the galaxy (not visible in this image). These dazzling objects all peak at the same brightness, and are brilliant enough to be seen over large distances. NGC 3972 also contains many pulsating stars called Cepheid variables. These stars change their brightness at a rate matched closely to their intrinsic luminosity, making them ideal cosmic lighthouses for measuring accurate distances to relatively nearby galaxies. Astronomers search for Cepheid variables in nearby galaxies which also contain a type Ia supernova so they …

19 February 2018: Neptune, the eighth and farthest planet from the Sun, was visited for the first and last time by NASA’s Voyager 2 mission in 1989. Since then, the NASA/ESA Hubble Space Telescope has been attempting to unearth the myriad mysteries surrounding this cool, majestic behemoth — including deciphering why it has the fastest wind speeds of any planet in the Solar System, and what lies at its centre. These new Hubble images reveal one of the standout features of Neptune’s strange atmosphere: a rare dark spot, or dark vortex — a whirling high-pressure atmospheric system usually accompanied by bright “companion clouds”. This particular dark spot is named SDS-2015 (Southern Dark Spot discovered in 2015), and is only the fifth observed so far on Neptune. Although it appears to be slightly smaller than previous dark spots, observations of SDS-2015 from 2015 to 2017 revealed that the spot was once big enough to …

19 September 2016: This intriguing new image captured with the NASA/ESA Hubble Space Telescope shows a dust-bathed cluster of fragments from a disintegrated comet. The comet in question, named 332P/Ikeya-Murakami, split into this shower of fragments in the closing months of 2015. Fragmenting comets such as 332P/Ikeya-Murakami have long been objects of fascination for astronomers worldwide. Famously, Comet Shoemaker-Levy 9 disintegrated in 1992, crashing into the atmosphere of Jupiter at nearly 200 000 kilometres per hour, creating scars on it almost half the size of Earth. Though well-studied, objects such as this remain a puzzle to astronomers; no theory fully explains why comets split apart on their long journeys around the Sun. Hubble will continue to observe 332P/Ikeya-Murakami and comets like it, unravelling the nature of these mysterious objects.

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 …

4 May 2015: This image provides the clearest ever view of galaxy NGC 949, which lies over 30 million light-years away in the constellation of Triangulum. The galaxy has an unusual shape, made more obscure due to its inclination. From our point of view, it is difficult to discern exactly what type of galaxy NGC 949 is, but it is certainly a disc galaxy of some kind, most likely a spiral. NGC 949 was first discovered by Sir William Herschel on 21 September 1786, using an 18.7-inch reflecting telescope. The galaxy was one of about 3000 objects Herschel catalogued as "nebulae" during an intense and systematic deep sky survey, the results of which eventually formed the bulk of the New General Catalogue (NGC). Taken with Hubble’s Advanced Camera for Surveys (ACS), this new image shows extraordinary detail. This detail allows us to see a strange asymmetric alignment in the dark lanes of dust …

27 January 2014: A piece of art? A time-lapse photo? A flickering light show? At first glance, this image looks nothing like the images that we are used to seeing from Hubble. The distinctive splashes of colour must surely be a piece of modern art, or an example of the photographic technique of "light painting". Or, could they be the trademark tracks of electrically charged particles in a bubble chamber? On a space theme, how about a time-lapse of the paths of orbiting satellites? The answer? None of the above. In fact, this is a genuine frame that Hubble relayed back from an observing session. Hubble uses a Fine Guidance System (FGS) in order to maintain stability whilst performing observations. A set of gyroscopes measures the attitude of the telescope, which is then corrected by a set of reaction wheels. In order to compensate for gyroscopic drift, the FGS locks onto a fixed …