Veckans bild

16 maj 2016: On 16 March the names of the eight participants of #MeetESO — ESO’s first social media gathering — were announced, one month after the campaign’s launch. On 7 May 2016, the participants winged their way to Chile for a five-day visit to some of the most exciting astronomical facilities in the world: the Very Large Telescope (VLT) — the world's most advanced visible-light astronomical observatory — and the Atacama Large Millimeter/submillimeter Array (ALMA), the largest ground-based astronomical project in existence. As shown by their big smiles, the #MeetESO travellers fully enjoyed the packed itinerary, from engaging with ESO and ALMA staff during their night-time observations at one of the best locations on Earth, to staying at ESO’s Residencia, which acts as a hotel for working astronomers (but may be more familiar to many as the building that was “blown up” in the James Bond movie Quantum of Solace). The climax ...

9 maj 2016: This Picture of the Week shows the Vela ring galaxy, visible as a bright core surrounded by a baby blue halo. This ring galaxy — located in the southern constellation of Antlia (The Pump) — is notable due to its compact core and large circular belt of gas and stars. It is thought that ring galaxies like this are created when larger galaxies are punctured by a smaller galactic aggressor, which, passing through the heart of its more sizeable victim, triggers a shock wave that spreads outwards. This pushes gas to the galaxy’s periphery, where it begins to collapse and form new stars. The Vela ring galaxy is unusual in that it actually exhibits at least two rings, suggesting that the collision was not a recent one. This picture also features a galaxy known as ESO 316-33, seen just above and to the left of the Vela ring galaxy, and ...

2 maj 2016: Glistening against the awesome backdrop of the night sky above ESO’s Paranal Observatory, four laser beams project out into the darkness from Unit Telescope 4 (UT4) of the Very Large Telescope (VLT); they mark the first use of multiple lasers at ESO and they are the most powerful laser guide stars ever used in astronomy. Some 90 kilometres up in the atmosphere, the lasers excite atoms of sodium, creating artificial stars for the telescope’s adaptive optics systems. Modern telescopes use adaptive optics systems to compensate for the blurring effect of the Earth’s atmosphere. To do this, the telescope needs to be able to see a bright reference star while it is observing its main target. However, there is not always a suitably bright star nearby, so astronomers use lasers to create artificial stars exactly where they need them. Sodium atoms high in the atmosphere are made to glow by the ...

25 april 2016: Astronomers have discovered a new satellite orbiting the main belt asteroid (130) Elektra — the smallest object visible in this image. The team, led by Bin Yang (ESO, Santiago, Chile), imaged it using the extreme adaptive optics instrument, SPHERE, installed on the Unit Telescope 3 of ESO’s Very Large Telescope at Cerro Paranal, Chile. This new, second moonlet of (130) Elektra is about 2 kilometres across and has been provisionally named S/2014 (130) 1, making (130) Elektra a triple system. Exploiting the unprecedented sensitivity and spatial resolution of the instrument SPHERE, the team also observed another triple asteroid system in the main belt, (93) Minerva. Asteroids are the relics of the building blocks that formed the terrestrial planets in the early days of the Solar System. Studying asteroids with multiple satellites is of crucial importance because their formation mechanisms can provide information about planet formation and evolution that cannot be ...

18 april 2016: As the Sun raises at Cerro Paranal, in Chile, filling the sky with superb orange shades, two members of the ESO Fulldome Expedition, Babak Tafreshi (left) and Yuri Beletsky (right), are preparing their tripods and cameras for the day ahead. Above the silhouette of the Chilean mountains, the gentle smile of a crescent Moon and the bright planet Venus strike a pose for the cameras. Thanks to a phenomenon called earthshine, the entire disc of the Moon can be seen shining in light reflected off the Earth. The telescope in silhouette in front is an Auxiliary Telescope (AT), part of Very Large Telescope (VLT) at ESO's Paranal Observatory. This twilight moment was captured by ESO Photo Ambassador Petr Horálek, while participating in the ESO Fulldome Expedition which is gathering spectacular images for use in the ESO Supernova Planetarium & Visitor Centre, currently under construction at ESO’s Headquarters in Garching (near ...

11 april 2016: This Auxiliary Telescope at the Very Large Telescope (VLT), located at the Paranal Observatory in Chile, looks to be pointing at the greenish emerald glow of the comet 252P/LINEAR high above it. Discovered in April 2000, 252P/LINEAR is a relative newcomer to the inner Solar System, traveling between the orbit of Jupiter and the orbit of Earth. A couple of days ago, in March 2016, it passed particularly close to the Earth, at a distance of only 5.2 millions kilometers, ranking as the fifth closest recorded passage of a comet. It can still be admired in the southern hemisphere. The green colour arises from fluorescing carbon-based gas surrounding the comet. This gem of a picture was taken by the ESO Photo Ambassador Babak A. Tafreshi. He has just started out on ESO’s Fulldome Expedition, during which he will be taking more spectacular pictures from ESO’s observatories and of the southern ...

4 april 2016: The faint light extending up from the horizon just below centre of this photo is known as zodiacal light, caused by sunlight scattering from cosmic dust in the plane of our Earth’s orbit. A second band of light can be seen at the horizon on the lower left. This red light is airglow, produced by the Earth’s atmosphere. Airglow is caused by processes taking place in the upper atmosphere, including cosmic rays, recombining photoionized atoms, and various chemical reactions between oxygen, nitrogen, hydroxyl, sodium, and lithium atoms. The third and final band is the Milky Way, our home galaxy, high in the sky. This band consists of billions of stars of all kinds. Many of them are hidden to the human eye behind large layers of interstellar dust, giving the Milky Way its characteristically mottled look. At the centre of the image stands ESO Photo ambassador Babak Tafreshi, watching the ...

28 mars 2016: Deep in the Chilean Desert, astronomers staying at ESO’s Residencia, the VLT Observatory's hotel, witness a skyscape like few others on Earth. Designed by the German architects Auer+Weber+Assoziierte, the Residencia provides an oasis for those working at ESO’s Paranal Observatory. The Atacama Desert is one of the harshest landscapes imaginable. Extreme dryness, intense ultraviolet radiation from the Sun, and high altitude are a normal part of everyday life. However, come nightfall, the Residencia experiences some of the best observing conditions in the world. Residencia and ESO’s Very Large Telescope (VLT) — housed at the Paranal Observatory — are far from sources of light pollution, and experience exceptionally clear atmospheric conditions. On moonless nights, the sky can be so clear and dark that light from the Milky Way casts a shadow on the ground! These factors permit high quality scientific observations to be made as well as offering amazing conditions for ...

21 mars 2016: The dark patch snaking across this spectacular image of a field of stars in the constellation of Ophiuchus (The Serpent-bearer) is not quite what it appears to be. Although it looks as if there are no stars here, they are hidden behind this dense cloud of dust that blocks out their light. This particular dark cloud is known as LDN 1768. Despite their rather dull appearance, dark nebulae like LDN 1768 are of huge interest to astronomers, as it is here that new stars form. Inside these vast stellar nurseries there are protostars — stars at the earliest stage of their lives, still coalescing out of the gas and dust in the cloud. Protostars are relatively cold and have not yet begun to produce enough energy to emit visible light. Instead, they emit radiation at submillimetre wavelengths, which human eyes cannot see. Luckily, unlike visible light, light at submillimetre wavelengths ...

14 mars 2016: This picture was taken just before dawn at the La Silla Observatory, in outskirts of the Chilean Atacama Desert. A layer of orange hovering over the horizon announces the imminent arrival of the Sun. These first hints of daylight are kissed by the Milky Way, which stretches out across the entire night sky. This view of our home galaxy is covered with dark patches, formed from dust particles blocking the light behind them. In front of this cosmic scenery you can see some of the observatory’s telescopes. The closest is the Swedish–ESO Submillimetre Telescope (SEST), whose dish measures 15 metres across. It was decommissioned in 2003 and replaced by the Atacama Pathfinder EXperiment telescope (APEX) and the Atacama Large Millimeter/submillimeter Array (ALMA). On the plateau in the background stands the ESO 3.6-metre telescope, with the Coudé Auxiliary Telescope (CAT) right behind it. SEST seems to be pointing at an extremely ...

7 mars 2016: In this picture, our home galaxy the Milky Way stretches across the sky above the landscape of the Chilean Andes. In the foreground, the roads of ESO’s La Silla Observatory are packed with state-of-the-art astronomical telescopes pointing towards, and far beyond, the Milky Way. Several multinational telescopes are captured in this frame. The ESO 3.6-metre telescope stands on the central pedestal and is mounted with the High Accuracy Radial velocity Planet Searcher (HARPS) — the best exoplanet finder on Earth. Just next to the main dome, the smaller one once hosted the Coudé Auxiliary Telescope (CAT) which used to feed the powerful Coudé Echelle Spectrograph; they are now both decommissioned. At the foot of this pedestal lies the French Rapid Action Telescope for Transient Objects (TAROT) which follows up on highly energetic events called gamma-ray bursts. These are also studied by the Swiss 1.2-metre Leonhard Euler Telescope in the dome ...

29 februari 2016: Pictured here at sunset is one of the four Auxiliary Telescopes (ATs) of the Very Large Telescope Interferometer (VLTI), shown at ESO's Paranal Observatory. The faint crescent Moon can be seen hanging above the round enclosure of the telescope. Together with four Unit Telescopes (UTs) that make up the Very Large Telescope, these four ATs complete the VLTI. Unlike the UTs, which are fixed, each of the four 1.8-metre ATs are movable and can be relocated to 30 different stations along the platform to create a wide baseline of up to 200 metres. This allows the VLTI to act as one large telescope of this size via a technique called interferometry — combining the light from several smaller telescopes to increase the resolution of the telescope. In the case of VLTI, this provides milliarcsecond angular resolution — equivalent to a span of two metres as far away from us as ...

22 februari 2016: This image is unreal — literally! Rather than being a single picture, it was created by combining two separate photographs together, and shows the January sky as seen from both hemispheres. The skilled photographer was ESO Photo Ambassador Petr Horálek. Petr shot the upper part of the image from ESO’s Paranal Observatory in Chile and the lower part from the Slovakian village of Oravska Lesna, before combining the two to form this striking composite. One arm of the distinctive X-shaped structure spreading from the top right to the bottom left of the frame is the lane of the Milky Way. The other diagonal comprises glowing columns of zodiacal light. In the centre of the image, is one of the four small 1.8-metre Auxiliary Telescopes that make up part of ESO's Very Large Telescope (VLT). A significant glow can be seen in the lower part of the image, caused by light ...

15 februari 2016: This striking photograph from Yuri Beletsky captures many wonders — both terrestrial and astronomical — across an incredible distance scale. In the immediate foreground looms ESO’s VISTA survey telescope. This 4.1-metre telescope scans the skies in infrared light, picking out astronomical objects of interest so that they can be studied by the four 8.2-metre Unit Telescopes of ESO’s Very Large Telescope (VLT) facility. This facility can be seen on the mountaintop to VISTA’s right, about a kilometre up the road. In the sky above VISTA a luminous and dark-ribboned band runs from lower left to top right. This is the disc of the Milky Way, seen edge-on and looking inward toward the galactic core. Although we cannot see all the way to the core with our unaided eyes, we have gauged its distance as about 30 000 light-years from us. That distance works out as about 280 quadrillion kilometres, or ...

8 februari 2016: You may be wondering what a truck has to do with astronomy. Well, this is no ordinary truck — it is an ALMA transporter! At 20 metres long and 10 metres wide, this is one of a pair of custom-designed vehicles used to transport the 66 antennas that make up the Atacama Large Millimeter/submillimeter Array (ALMA). From its home at 5000 metres above sea level, high in Chile’s Atacama Desert, ALMA delivers a unique view of the low temperature Universe, allowing astronomers to study how stars form in unprecedented detail. The trucks — this one is called Lore, its sibling is Otto — move each antenna along the 28-kilometre road from the construction area at just below 3000 metres above sea level, up to the main telescope site, around 2000 metres higher. They are then used to move the antennas into different configurations corresponding to the different observing modes of ...

1 februari 2016: This picture of the week shows the spiral galaxy NGC 986 in the constellation of Fornax (The Furnace). The galaxy, which was discovered in 1826 by the Scottish astronomer James Dunlop, is not often imaged due to its proximity to the famous and rich Fornax Cluster of galaxies. Which is a shame, as this galaxy is not only a great scientific object, but also very pretty. The galaxy is about 56 million light-years away and seen almost perfectly from the top, or — as astronomers say — face-on. This allows us to see the two main spiral arms and also a central bar-shaped structure, composed of stars and dust, which makes it a barred spiral galaxy. Astronomical surveys have shown that about two thirds of all spiral galaxies contain a bar, including the Milky Way. This makes NGC 986 the perfect place to study the structure of galaxies and find ...

25 januari 2016: In the sky above ESO's La Silla Observatory, the Southern Cross is clearly visible just to the right of the dome of the Danish 1.54-metre telescope, and to the lower right of the image, two stars sparkle in the amazingly dark sky. From right to left, these are Alpha and Beta Centauri. Alpha Centauri is a multiple star, the nearest star system to Earth. A little closer to Earth than the bright components of Alpha Centauri, and invisible to the naked eye, is Proxima Centauri, the third star belonging to this multiple star system. It is our closest neighbour, at a distance of just 4.2 light-years. Previous observations have provided tantalising, but subtle, hints of a small companion orbiting this red dwarf star. An observing campaign that started in January 2016 will make a more sensitive search for the telltale wobbles in the dwarf star’s orbital motion that might reveal ...

18 januari 2016: The Milky Way contains hundreds of billions of stars. However, the star at the centre of this image still manages to be very unusual — no mean feat! A Brazilian–American team led by Jorge Melendez, from the University of São Paulo used two of ESO’s telescopes in Chile to discover that this star, named 2MASS J18082002–5104378, is a rare relic from the Milky Way’s formative years. As such, it offers astronomers a precious opportunity to explore the first stars that sprung to life within our galaxy. 2MASS J18082002–5104378 was spotted in 2014 by ESO’s New Technology Telescope (NTT). Follow-up observations using ESO’s Very Large Telescope (VLT) discovered that, unlike younger stars such as the Sun, this star shows an unusually low abundance of what astronomers curiously call metals — elements heavier than hydrogen and helium. In fact, it is so devoid of these elements that it is known as an ...

11 januari 2016: This picture, taken at the La Silla Observatory in Chile, shows the full Moon low in the purple sky, a photographer crouching on the rocks, and the New Technology Telescope (NTT) perched on a hilltop. This image depicts the three things we need for observational astronomy: An object to observe, a telescope to observe it, and a person to make sense of the observations. The Moon is the closest celestial body to Earth and orbits at a distance of 400 000 kilometres as our only natural satellite. Despite the aesthetic glow of the full Moon in this image, the Moon is not a great friend to astronomers. Sunlight that reflects off the lunar surface causes light pollution and makes it harder to observe more distant and very faint objects. Light pollution does not, however, bother the man admiring the view here. This is Babak A. Tafreshi, one of ESO's Photo ...

4 januari 2016: These friendly looking creatures, photographed in front of the ESO 3.6-metre telescope at the La Silla Observatory, are Guanacos. Guanacos, alongside the Vicuña, are one of two types of wild camelid native to this region of northern Chile. Reaching between one and two metres in length (from their heads to their tails) and weighing up to 120 kilograms, guanacos are one of the largest land mammals in Chile. These intrepid adventurers can be found in Bolivia, Paraguay, Argentina, and throughout the Andes: from Tierra del Fuego in the extreme south of Chile all the way up to Peru. Thriving on the feasts of the desert flora, guanacos enjoy mushrooms, grasses, leaves, trees and even some types of cactus flowers as part of their diets. Guanacos and vicuñas are no stranger to ESO’s facilities in the Atacama Desert. In February 2014 a vicuña fawn was rescued by ESO staff when it ...