Picture of the Week

30 April 2018: A sinister smile appears amid a sea of stars in this image — a small portion of a gigantic gigapixel colour mosaic of the Milky Way’s heart. Comprised of thousands of incredibly detailed images taken by ESO’s Visible and Infrared Survey Telescope for Astronomy (VISTA), the mosaic reveals more of the stars at the Milky Way’s heart than ever before. VISTA was chosen due to its extremely sensitive infrared camera, which can see through most of the dust that blocks our view towards the centre of the galaxy. What we see in this image is a dense patch of gas and dust — a nebula — that even VISTA’s camera cannot see through. Located near the Lagoon Nebula (not seen), it appears to wink back as it mischievously blocks out the light from background stars. The full image contains almost nine billion pixels, and is part of the Vista Variables ...

23 April 2018: This unusual image shows three of the telescopes sited at ESO’s La Silla observatory in Chile — the MPG/ESO 2.2-metre telescope on the left, ESO’s 3.6-metre telescope sitting in the distance behind it, and the Danish 1.54-metre telescope on the right, apparently looming over its companions in the foreground. Of course, this is a highly distorted view of the telescopes! This photograph was taken by ESO Photo Ambassador Petr Horálek to emphasise not the telescopes themselves but the stunning features of the night sky above the observatory site, which is one of the best in the world. This is a long-exposure shot intended to capture the apparent motion of the stars as they circle slowly overhead in the sky. Over time, the stars appear to drag out trails of light in the sky — known as star trails — painting large circles onto the dark cosmos (this phenomenon is actually ...

16 April 2018: This breathtaking view of ESO’s Paranal Observatory reveals a spectacular night scene over part of ESO’s Very Large Telescope (VLT), the observatory’s most famous resident. The telescope sitting centre stage is one of the VLT’s four Unit Telescopes (UT). The VLT comprises both these UTs and four additional, movable, Auxiliary Telescopes (ATs). However impressive the VLT may be, the closed telescope is trumped in this image by the skies overhead — most prominently by the colourful plane of our home galaxy, the Milky Way, as it arches across the frame and creates a celestial rainbow. Part of the sky is tinted a faint green colour due to a phenomenon known as airglow, and the two smudges of the Magellanic Clouds can be seen to the left of the UT. The famous constellation of Orion (The Hunter) is visible to the right of centre, the bright stars of which can be ...

9 April 2018: Light travels to the telescopes at ESO’s La Silla Observatory in Northern Chile over vast distances, from the planets and moons within the Solar System, and from the distant stars of the Milky Way and beyond. This spectacular Ultra High Definition panorama of the observatory, created by ESO Photo Ambassador Babak A. Tafreshi, captures light from a wide range of celestial objects. Two of the most prominent sources of light in this spectacular shot are the Large and Small Magellanic Clouds, which can be seen as two diffuse fuzzy patches at the centre of the photo. These two galaxies are located 160 000 and 200 000 light-years away from us. The nearest celestial object in this starry scene is Mars, shining next to the open dome of the 1.54-metre Danish telescope in the foreground. At the time of this photograph, the red planet was 93 million kilometres from Earth. Venus, ...

2 April 2018: This unique image from ESO’s VLT Survey Telescope (VST) reveals two galaxies at the very beginning of the merging process. The interactions between the duo have created a rare effect known as a light echo, where light reverberates around the material within each galaxy. This is analogous to the acoustic echo where the reflected sound arrives at the listener with a delay after the direct sound. This is the first case of a light echo observed between two galaxies. The larger galaxy, seen here in yellow, is ShaSS 073 — an active galaxy with an extremely luminous core. Its less massive companion, in blue, is named ShaSS 622, and together the pair make up the intriguing ShaSS 622-073 system. The bright core of ShaSS 073 is exciting a region of gas within the disc of its blue companion: it bombards the material there with radiation, causing it to glow brightly ...

26 March 2018: This week’s featured image highlights a handful of the telescopes residing at ESO’s La Silla Observatory in northern Chile. The star of the show, framed perfectly by the beautiful arch of the Milky Way, sits directly in the middle of the photograph — the Danish 1.54-metre telescope. Operational since 1979, this trusty telescope has helped astronomers to make all kinds of cosmic discoveries, from understanding more about violently merging neutron stars to detecting planets around other stars. It now performs follow-up observations of gamma-ray bursts, some of the most energetic events in the Universe. This image, taken by ESO Photo Ambassador Petr Horálek, shows the heart of the Milky Way, both the Large and Small Magellanic Clouds, the constellations of Orion (The Hunter) and the Southern Cross, and the glare of distant settlements, all of which create vibrant bursts and flashes of colour across the frame. Towards the distant horizon, ...

19 March 2018: This spectacular shot from ESO’s La Silla Observatory in Chile was captured by by ESO Photo Ambassador Yuri Beletsky, and reveals all manner of astronomical treats! The central plane of our galaxy stretches, slightly curved, across the frame, peppered with bright patches of gas and dark, weaving dust lanes. Although initially a little hard to see against the intricate cosmic backdrop, the constellation of Orion (The Hunter) can be seen to the top left of the frame. Multiple pink clouds, produced by the faint glow of ionised hydrogen gas, appear to extend beyond the band of the Milky Way, indicating the presence of hot, young new stars. One of these areas is Barnard's Loop, which encircles the famous Orion Nebula and can be seen curving around Orion’s Belt. The MPG/ESO 2.2-metre telescope sits beneath the colourful night sky, where it is currently involved in research chasing the aftermath of some ...

12 March 2018: A sweeping blanket of stars gazes serenely down over Cerro Paranal, Chile, as the rising Sun gently warms the horizon with splashes of red and yellow. Cerro Paranal is home to ESO’s Very Large Telescope (VLT) — and this striking panorama reveals the telescope in all its glory. All four of the VLT’s large 8.2-metre Unit Telescopes are visible along the left side of the image, lined up and ready to explore the Universe. Two smaller 1.8-metre Auxiliary Telescopes can be seen scattered across the right side of the frame; the VLT has four of these in total, all of which are movable along a grid of tracks, and can be rearranged as needed. In the distance, the 2.6-metre VLT Survey Telescope (VST) — the newest addition to Paranal — can be seen just beyond the rightmost Unit Telescope. Above and between the two leftmost Unit Telescopes, the mighty extent ...

5 March 2018: All of ESO’s observatories are based in Chile, but the organisation’s headquarters, and the newest exciting addition sits in Garching, a small city near Munich in Germany. This image shows a striking and unusual view of this new member of the ESO family — the ESO Supernova Planetarium & Visitor Centre. The ESO Supernova has its official inauguration event on 26 April and will open for the public on 28 April. At its heart, the Supernova is a truly state-of-the-art planetarium that will visualise and project accurate, awe-inspiring, and fully immersive views of the Universe for audiences to enjoy. The building also houses a cutting-edge astronomy centre and exhibition space. To make things even more appealing, attendance and all activities will be free throughout 2018! This image was taken by ESO Photo Ambassador Petr Horálek, reveals the curved arms of ESO headquarters reaching out toward the unique Supernova building, below ...

26 February 2018: Nestled in the young Ophiuchus star-forming region, 410 light-years from the Sun, a fascinating protoplanetary disc named AS 209 is slowly being carved into shape. This wonderful image was captured using the high-resolution ALMA telescope, revealing a curious pattern of rings and gaps in the dust surrounding a young star. Protoplanetary discs are dense, rotating planes of gas and dust that surround newly formed stars; providing the matter that one day becomes orbiting planets, moons and other minor bodies. At less than one million years old, this system is very young, but already two clear gaps are being sculpted from the disc. The outer gap is deep, wide, and largely a dust-free zone, leading astronomers to believe that a giant planet almost the mass of Saturn is orbiting here — around 800 light-minutes from the central star, and more than three times the distance between Neptune and the Sun! As ...

19 February 2018: This image, taken by ESO Photo Ambassador Petr Horálek, shows the planet Venus shining brightly over ESO’s Paranal Observatory in Chile at twilight. The featured telescope is the Very Large Telescope’s Auxiliary Telescope 1, open and preparing itself to observe the night sky, which is splashed in shades of blue and orange. ESO’s Very Large Telescope (VLT) comprises four 8.2-metre Unit Telescopes, and four 1.8-metre Auxiliary Telescopes (ATs) — like the one posing in the foreground of the image — whose captured light can be combined to form the VLT Interferometer (VLTI). By combining the light from multiple telescopes positioned in different places across the observatory site, the VLTI allows astronomers to see details up to 25 times finer than with the individual telescopes. The light beams are then combined using a complex system of mirrors in underground tunnels where the light paths must be kept equal to distances less ...

12 February 2018: This ghostly image features a distant and pulsating red giant star known as R Sculptoris. Situated 1200 light-years away in the constellation of Sculptor, R Sculptoris is something known as a carbon-rich asymptotic giant branch (AGB) star, meaning that it is nearing the end of its life. At this stage, low- and intermediate-mass stars cool off, create extended atmospheres, and lose a lot of their mass — they are on their way to becoming spectacular planetary nebulae. While the basics of this mass-loss process are understood, astronomers are still investigating how it begins near the surface of the star. The amount of mass lost by a star actually has huge implications for its stellar evolution, altering its future, and leading to different types of planetary nebulae. As AGB stars end their lives as planetary nebulae, they produce a vast range of elements — including 50% of elements heavier than iron ...

5 February 2018: This unusual image reveals the aftermath of a catastrophic collision between two galaxies, which happened about one billion years ago. The result? A single, very oddly shaped galaxy named NGC 7252, and curiously nicknamed the Atoms for Peace galaxy. At the heart of this merger remnant lies a fascinating “minispiral” — a rotating disc of glowing gas, bursting with star formation. Using the VIsible Multi-Object Spectrograph (VIMOS) instrument on ESO’s Very Large Telescope, astronomers were able to measure the movement of the gas within this disc, allowing them to map its rotation. Red regions indicate gas moving away from us, and blue regions towards us. Together, these colours reveal the galaxy's steadily rotating centre, as well as highlighting two flowing streams of hot gas north-west and south-east of the central region. Past studies suggested that the central spiral was rotating counter to the rest of the galaxy, but by comparing ...

29 January 2018: Squint or you’ll miss it! At the very centre of this image, taken with the VIMOS instrument attached to ESO’s Very Large Telescope (VLT), you can just about see the faint and fuzzy blue form of a distant galaxy known as the Sagittarius Dwarf Irregular Galaxy. Discovered in 1977 with the ESO 1-metre Schmidt telescope, situated at ESO’s La Silla observatory, the irregularly shaped — hence the name — dwarf galaxy is approximately 3 million light-years away in the constellation of Sagittarius (The Archer). It is the most distant member of the Local Group of galaxies, of which the Milky Way is a member. Unlike normal galaxies, dwarf galaxies are typically smaller and host a relatively small number of stars. Gravitational tugs from nearby galaxies can often distort the spherical and disc-like shapes of these fragile galaxies — this very process may be responsible for the slightly rectangular shape of ...

22 January 2018: The rugged terrain of the Chilean Atacama Desert offers a truly striking backdrop for photographs — as evidenced by this snap of ESO’s Visible and Infrared Survey Telescope for Astronomy (VISTA), taken by ESO Photo Ambassador Alexandru Tudorică at ESO’s Paranal Observatory. Although it is by far Tudorică’s most prominent subject, VISTA is not the only telescope visible in this image. The snaking path trailing off to the right side of the image leads to the inconspicuous enclosure of the Next Generation Transit Survey (NGTS) — the enclosure itself is just about visible to the far right of the frame, illuminated by a sliver of sunlight. The NGTS comprises an array of small robotic telescopes that constantly and precisely monitor the brightness of nearby stars. By doing so, it hopes to catch exoplanets the size of Neptune in the act of blocking out light from their parent stars as they ...

15 January 2018: These 56 smiling students took part in ESO’s Winter Astronomy Camp 2017, which explored the theme of “Distances in the Universe”. The young astronomy enthusiasts enjoyed several astronomical sessions, including lectures, hands-on activities and night-time observations using professional telescopes. They also tried their hand at various winter sports and excursions. The Camp was held at the Astronomical Observatory of the Autonomous Region of the Aosta Valley, surrounded by the natural beauty of the Italian Alps, close to some of Europe’s highest mountains and under some of the clearest skies. The observatory is equipped with seven telescopes that were devoted to camp activities. The camp, organised by Sterrenlab, took place between 26 December 2017 and 1 January 2018, and was open to students aged 16–18. Later this year, the ESO Summer Astronomy Camp will be held under the dark skies of northern Portugal, organised by the Centre for Astrophysics of the ...

8 January 2018: The first evening of the new year was beckoned in by a spectacular supermoon, rising up from behind the majestic Cerro Armazones mountain in Chile. A supermoon like this is a magnificent, albeit relatively frequent, occurrence which takes place when a full moon coincides with the point in the lunar orbit that is closest to Earth, its diameter appearing about 14% larger in the sky. The road zigzagging up Cerro Armazones appears to lead directly to the Moon itself — truly making it a road to the stars. By 2024, the “world’s biggest eye on the sky” will rest on top of this mountain, as its peak will be home to the Extremely Large Telescope. At an altitude of 3046 metres, Cerro Armazones provides a spectacular environment for astronomical observations, in particular because it receives 320 clear nights per year. This photo was captured by ESO Photo Ambassador Gerhard Hüdepohl. ...

1 January 2018: This week’s picture shows spectacular ribbons of gas and dust wrapping around the pearly centre of the barred spiral galaxy NGC 1398. This galaxy is located in the constellation of Fornax (The Furnace), approximately 65 million light-years away. Rather than beginning at the very middle of the galaxy and swirling outwards, NGC 1398’s graceful spiral arms stem from a straight bar, formed of stars, that cuts through the galaxy’s central region. Most spiral galaxies — around two thirds — are observed to have this feature, but it’s not yet clear whether or how these bars affect a galaxy’s behaviour and development. This image comprises data gathered by the FOcal Reducer/low dispersion Spectrograph 2 (FORS2) instrument, mounted on ESO’s Very Large Telescope (VLT) at Paranal Observatory, Chile. It shows NGC 1398 in striking detail, from the dark lanes of dust mottling its spiral arms, through to the pink-hued star-forming regions sprinkled ...

25 December 2017: This image shows something spectacular: a galaxy cluster so massive that it is warping the space around it! The cluster, whose heart is at the centre of the frame, is named RCS2 J2327, and is one of the most massive clusters known at its distance or beyond. Massive objects such as RCS2 J2327 have such a strong influence on their surroundings that they actually warp the space around them — this effect is known as gravitational lensing, and can cause light from more distant objects to be bent, distorted, and amplified, allowing us to see galaxies that would otherwise be far too distant for us to detect. Gravitational lensing is one of the predictions of Albert Einstein's General Theory of Relativity and can be observed in three different regimes: strong lensing, weak lensing, and microlensing. Unlike strong lensing, which produces stunning images of distorted galaxies, sweeping arcs, and phenomena known ...

18 December 2017: Season's Greetings on behalf of everyone at the European Southern Observatory! We wish you a jolly end of the year and a fruitful 2018! Links Christmas card 2017