Picture of the Week 2020

23 March 2020: The entire Universe is constantly on the move, from individual atoms all the way up to massive galaxy clusters. This is beautifully showcased in an image such as this, taken from the Chajnantor plateau some 5000 metres up in the Chilean Atacama Desert. This extremely arid and remote environment is home to the Atacama Large Millimeter/submillimeter Array (ALMA), the largest telescope array in existence. The blurred object is a specialised transporter, caught in the act of carefully carrying one of ALMA’s 66 high-precision antennas to a specific position on the plateau. By arranging the antennas in more extended configurations, astronomers can obtain far more highly spatially resolved images (meaning that the image is more detailed), while more compact configurations give better sensitivity for sources which spread over more of the sky. There’s movement going on above, too. Smooth stretches of cloud sweep across the pristine Chilean sky under the ...

16 March 2020: This picture of the week showcases the night sky over the construction site for the Extremely Large Telescope. A beautiful array of stars and the hazy band of the Milky Way are clearly visible above the site. In order to see the Milky Way so distinctly, one must be in an area with low light pollution, such as the Chilean mountain Cerro Armazones, when there is little or no moonlight. The ELT will be “the world’s biggest eye on the sky” when it begins operating. With a 39-metre primary mirror, the ELT will search the sky in the optical and near-infrared wavelength regions for new exoplanets, specifically Earth-like planets in orbit around other stars. The ELT will also be able to perform a kind of “stellar archaeology,” answering fundamental questions about how planets, primordial stars, primordial galaxies and black holes form and evolve. Perhaps the most exciting goal of the ...

9 March 2020: This beautiful image shows the dense heart of the Milky Way stretched out above one of the Auxiliary Telescopes of ESO's Very Large Telescope (VLT). Such dark and star-studded skies are typical of the VLT’s location in the Chilean Atacama Desert, which offers spectacular views such as this night after night for all of the site’s astronomers, visitors, and staff to enjoy. The VLT is made up of four large Unit Telescopes, and four smaller and movable Auxiliary Telescopes (one of which is shown here). These eight telescopes observe the cosmos both individually and as a team from various orientations and positions, allowing astronomers to study all manner of cosmic objects and phenomena in greater detail than ever before. The array has stimulated a new age of discoveries, with several notable scientific firsts — including the first image of a planet orbiting another star (known as an ...

2 March 2020: The soft glow of the Milky Way pours down like a waterfall over the VLT Survey Telescope (VST) at ESO’s Paranal Observatory. 2635 metres above sea level, the VST has an unparallelled view of the magnificently clear skies above Chile’s Atacama Desert. It is the largest telescope in the world dedicated to observational surveys in visible light, and it contributes to a vast range of studies, from discovering remote Solar System bodies to searching for exoplanet transits, to studying the structure and evolution of our galaxy. Above the VST, a few stars are particularly prominent just outside the main band of the galaxy: the bright reddish star is Betelgeuse, a red supergiant 640 light-years away thought to be on the brink of a supernova explosion. Betelgeuse and Bellatrix, the fainter white star to its left, are the shoulders of Orion the Hunter, one of the most famous and easily recognisable ...

24 February 2020: A new study led by Pierre Vernazza (Laboratoire d’Astrophysique de Marseille, France) conducted using ESO facilities has observed the asteroid Pallas for the first time at extremely high angular resolution. The asteroid could be successfully observed in such great detail thanks to the Adaptive-Optics (AO)-fed SPHERE imager on the Very Large Telescope (VLT). German astronomer Heinrich Wilhelm Matthäus Olbers first discovered Pallas on 28 March 1802. Named for the Greek goddess Pallas Athene, the asteroid — along with many other asteroids discovered in the 19th century — was initially classified as a planet. As time passed and technology improved, Pallas was later reclassified as an asteroid. Today it is famous for being the third-largest asteroid in the Solar System, with an average diameter of 512 km. Although Pallas is the largest known asteroid in the Solar System after Ceres and Vesta, it is the only one of these large asteroids ...

17 February 2020: Located deep in the Chilean Atacama Desert, far from the light pollution associated with human activity, is ESO’s Paranal Observatory: a world-leading research site that enjoys some of the darkest skies on Earth. Paradoxically, it is this extreme darkness that allows the sky to light up in technicolour in this image. The striking radiant light visible in the sky here is a phenomenon called airglow, which lends a magical appearance to the already breathtaking night sky. As the name suggests, airglow is a faint glow in the air created as atoms and molecules in the atmosphere combine and emit radiation. It is only visible in regions where the sky is dark enough that artificial lights do not overwhelm it. This phenomenon was the subject of ESOcast 78. This perspective was captured from the site of VISTA, the Visible and Infrared Survey Telescope for Astronomy. The trail of ...

10 February 2020: Stars are surrounded by something known as a corona — a diffuse aura of plasma that appears to surround them in the sky. For the Sun, we can best see this corona during a solar eclipse, when the Moon passes in front of the Sun and covers our star’s face. The solar corona then appears as a bright ring surrounding the eclipsed Sun. An image of the Sun’s corona as seen during a 1999 eclipse can be seen here. However, there is also the optical phenomenon of a corona, caused by the diffraction of light from a bright object — such as the Sun, other stars, the Moon, and bright planets — by water drops or ice crystals in the Earth’s atmosphere. This is occurring in this unusual image, where a rare corona of the planet Jupiter can be seen above the Atacama Desert in Chile. The beautiful red ...

3 February 2020: This remarkable photo shows the ESO La Silla observatory in the foreground with the planets Venus and Jupiter low in the sky and the Milky Way drifting behind them. Yet it took Zdenek Bardon, the photographer, three nights to capture this stunning image; astrophotographers are subject to the whims of the weather and this photo was no exception. He had to wait three days for a crystal clear night with no clouds and low humidity to capture Venus, Jupiter and the Milky Way in all their glory. La Silla is an exceptional location for astronomy because it has relatively low light pollution which allows the stars to appear crystal clear — although lights from human dwellings are visible on the horizon in this image. The site also offers exceptionally low humidity thanks to its elevation of 2400 metres above sea level. High humidity is a problem for both professional astronomers ...

27 January 2020: In this photograph, taken by ESO Photo Ambassador Babak Tafreshi, a slice of fiery colour streaks along the horizon near Paranal Observatory in northern Chile, bathing the four Unit Telescopes of the Very Large Telescope (VLT) in a soft, peachy glow. The Milky Way appears to soar directly up from one of the Unit Telescopes, bounded on either side by a spectacular array of stars — including Sirius, which dazzles at the top of the image. Part of Canis Major (The Greater Dog), Sirius is the brightest star in the sky and is actually a binary system, consisting of a main-sequence star (Sirius A, a star in stable “adulthood” that is burning nuclear fuel) and a white dwarf (Sirius B, the dense corpse of a star that ran out of fuel long ago). Wander down the edge of the Milky Way, and you might spy a small group of bright ...

20 January 2020: The Milky Way contains many regions of starbirth — areas where new stars are springing to life within collapsing clumps of gas and dust. One such region, named Gum 26, is shown here as imaged by the FORS instrument on ESO’s Very Large Telescope in Chile. Gum 26 is located roughly 20,000 light-years away in the southern constellation of Vela (The Sails). It is something known as an HII region or emission nebula, where the intense ultraviolet radiation streaming from newly-formed stars ionises the surrounding hydrogen gas, causing it to emit a faint pinkish glow. By catching new stars “pink-handed” in this manner, astronomers can learn more about the conditions under which stars arise, and study how they influence their cosmic environment. This image was created as part of the ESO Cosmic Gems programme, an outreach initiative to produce images of interesting, intriguing or visually attractive objects using ESO telescopes, ...

13 January 2020: Once used as the otherworldly lair for a James Bond villain, the ESO Residencia usually serves a far less sinister purpose! Since construction was completed in 2002, it has been a home from home for the astronomers, engineers and technicians working at ESO’s Paranal Observatory in Chile. The sleek building sits 2400 metres above sea level in the Mars-like Atacama Desert, just a few kilometres from Cerro Paranal — the mountain that hosts ESO’s Very Large Telescope (VLT) and Visible and Infrared Survey Telescope for Astronomy (VISTA). During the day the hotel is bathed in natural sunlight, which enters the building via a huge 35-metre-diameter dome on the roof. Seen here at night, the glass of the dome is beautifully illuminated beneath the Milky Way’s kaleidoscopic arch of blues, reds and pinks. Two neighbouring galaxies — the Large and Small Magellanic Clouds — can be seen as white smudges beneath ...

6 January 2020: Compared to their more intricate spiral cousins, elliptical galaxies resemble soft, hazy clouds. These galaxies have smooth, undefined boundaries, and bright cores surrounded by a fuzzy, diffuse glow. However, looks can be deceiving. At least 10% of ellipticals extend much further out into the cosmos than you might expect, and possess a range of far finer structures than first meets the eye — features such as loops and shells. Located around 100 million light-years away in the constellation of Pisces (The Fish), the galaxy to the upper-left of this image is named NGC 474. It is a stunning example of a shell elliptical galaxy; enormous wispy tails flick around the galaxy’s main body, while the inner structure is formed of a series of nested concentric rings. In fact, the full extent of the galaxy cannot even be contained in this field of view. The tendril-like outer regions of NGC 474 ...