ESO

@eso

The European Southern Observatory designs, builds & operates world-class observatories on the ground for the benefit of society. More info on eso.org

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ESO@eso· 27d

Beta Pictoris d is only 2.4 times more massive than Jupiter, making it one of the lightest exoplanets ever imaged from the ground. Its two other siblings are each around ten times the mass of Jupiter. Read more: https://www.eso.org/public/news/eso2609 🔭 🧪 3/3 📹 ESO/B. Sutlieff, M. Bonse et al.

ESO@eso· 27d

Known as Beta Pictoris d, it is the faintest exoplanet ever directly imaged from Earth. This is a major feat, as direct imaging only works for #exoplanets bright enough to show up next to their much brighter host stars. How does the newcomer compare to its siblings? 🔭 🧪 2/3

Six-panel montage of observations of the same star system taken between 2014 and 2025 with ESO’s VLT (SPHERE and ERIS instruments) and the James Webb Space Telescope (NIRCam). In each panel, the central star is hidden behind a coronagraph and marked with a white star symbol. A faint companion, highlighted by a white arrow, is visible at different positions over time.

ESO@eso· 27d

Ten years of hide-and-seek! 🫣 Astronomers used our VLT to find a new #exoplanet orbiting the famous star Beta Pictoris — hiding in archival ESO observations spanning over a decade! And it's shyer than any exoplanet we've imaged before. 🔭 🧪 1/3 📷 ESO/B. Sutlieff, M. Bonse et al.

Image of a star system. The central star is hidden behind a coronagraph, marked by a white star symbol at the centre. A bright companion appears to the left, while a much fainter companion, indicated by a white arrow, is visible to the right against a reddish-orange background.

ESO@eso· 27d

Trip to a dead star 🧑‍🚀 Visit one of our closest neighbouring galaxies, the Small Magellanic Cloud — home to an elusive stellar corpse buried among filaments of gas left behind by a 2000-year-old supernova explosion. 🔭

ESO@eso· 28d

Beneath this breathtaking splatter of stars, the road to our La Silla Observatory is home to a rich variety of telescopes. In the foreground we can see the Danish 1.54-metre telescope, followed by the MPG/ESO 2.2-metre telescope & our New Technology Telescope in the background. 🔭 #flashback

A night sky filled with stars. The band of the Milky Way arches above three observatory domes on a dark, mountainous landscape.

ESO@eso· 29d

Small but mighty 💪 As the Sun sets, the MPG/ESO 2.2-metre telescope at La Silla opens its eye, preparing to peer into the sky above. While 2.2-metre may be modest by today’s standards, it still does a lot of excellent work! Here's what it explores: https://www.eso.org/public/images/potw2628a 🔭 🧪

A black and white photograph in portrait. In the bottom third of the image, in the foreground, is a cylinder-shaped building with a shiny dome. Three similar-shaped buildings are in the background. The top third of the image is filled by a wispy white cloud. Image by L. Sbordone/ESO

ESO@eso· Jul 9

Could you move 3,500 tonnes by hand? 😲 You could if you were an engineer at the construction site of our ELT, carrying out rotation tests of the telescope’s structure. 🔭 🧪 #instrumentation 1/2

ESO@eso· Jul 9

A Bubbly Cosmic Celebration 🍾 In the brightest region of this nebula, gas is heated by young stars & expands into the surrounding cooler gas. Once the heated hydrogen reaches the borders of the gas cloud, it bursts outwards into the vacuum like the contents of an uncorked champagne bottle 🔭 1/2

Close-up view of a glowing red nebula set against a dense star field. A bright white region near the upper right illuminates surrounding clouds of gas and dust. Numerous blue-white stars are scattered throughout the image.

ESO@eso· Jul 8

What have we accomplished over the past year? Check out our Annual Report to find out: https://www.eso.org/public/announcements/ann26004 Spoiler alert: ➡️ ELT construction progress ➡️ VLTI & GRAVITY+ milestone ➡️ CTAO-South groundbreaking ceremony ➡️ Discoveries ➡️ Protection of dark & quite skies

ESO@eso· Jul 8

Fancy a visit to the cosmic spider? 🚀 🕷️ Located 160 000 light-years away, the Tarantula Nebula is the most spectacular feature of the Large Magellanic Cloud. It is also the brightest and most energetic star-forming region in the Local Group of galaxies. 🔭

ESO@eso· Jul 7

A colourful view of the star cluster NGC 3532 ✨ Some of the stars in this cluster still shine with a hot bluish colour, but many of the more massive ones have become red giants and glow with a rich orange hue. 🔭 #flashback

Wide-field image of a star cluster. Thousands of stars of varying brightness and colour fill the scene, with bright blue-white stars interspersed among orange and red stars.

ESO@eso· Jul 7

ICYMI The 3I/ATLAS comet might be older than the Sun itself ☄️ Our VLT studied the composition of the brightest interstellar object ever spotted and found that it likely originated in the outskirts of an old star system, possibly making it much older than our star. Video summary👇 🔭 🧪

ESO@eso· Jul 6

The findings are in line with a similar, recent study by the James Webb Space Telescope. Read more: www.eso.org/public/news/... The trajectory of interstellar comet 3I/ATLAS as it crossed our Solar System over the course of 2025 and 2026 👇 📹 ESO/spaceengine.org 🔭 🧪 4/4

ESO@eso· Jul 6

Specifically, they measured ratios of carbon & nitrogen isotopes in cyanide molecules in the gas around the comet — indicators of a comet’s origin, as they are sensitive to the physical conditions in the formation environment and do not change much as the comet travels on through space. 🔭 🧪 3/4

Composite graphic showing the interstellar comet 3I/ATLAS (left) and part of its spectrum (right). The image of the comet shows a bright, glowing nucleus with a faint bluish tail. The graph displays the comet's spectral measurements, plotting brightness against wavelength shift. Highlighted regions mark the spectral signatures of the carbon isotopes ¹²C and ¹³C, with data points and a fitted curve showing the measured signal. Graphic by ESO/C. Opitom, J. Manfroid et al. Comet image: O. Hainaut

ESO@eso· Jul 6

By measuring specific chemical fingerprints, they found that 3I/ATLAS likely originated in the outskirts of an old star system. VLT time-lapse of 3I/ATLAS 👇 📹 ESO/O. Hainaut 🔭 🧪 2/4

ESO@eso· Jul 6

Older than the Sun! ☀️ Using our VLT, astronomers have studied in detail the composition of interstellar comet 3I/ATLAS ☄️ The findings shine new light on the formation history of this comet, indicating that it may be much older than the Sun. 🔭 🧪 📷 ESO/O. Hainaut 1/4 🧵👇

A bright comet near the centre-right of the frame, with a diffuse tail extending to the left. Numerous background stars appear as dotted streaks

ESO@eso· Jul 6

By measuring specific chemical fingerprints they found that 3I/ATLAS likely originated in the outskirts of an old star system. VLT time-lapse of 3I/ATLAS 👇 📹 ESO/O. Hainaut 🔭 🧪 2/4

ESO@eso· Jul 6

This photo was taken when the ELT construction reached an important milestone: for the first time, the telescope’s structure was rotated horizontally by a few centimetres...by hand! 🔭 🧪 2/3

The interior of the Extremely Large Telescope. The metallic grey main structure can be seen in the entire picture, with three people standing in front of it, in hard hats and green safety vests. The people are much smaller than the telescope’s structure.

ESO@eso· Jul 6

This is why we call it the Extremely Large Telescope! This photo shows the massive, 39-metre-diameter structure that will hold the main mirror of our ELT. 798 mirror segments will sit here, working together as a single mirror, in what will be the biggest optical telescope on Earth. 🔭 🧪 1/3

ESO@eso· Jul 2

A new ESO study has found devastating consequences for astronomy from these current plans. #ChasingStarlight host Suzanna Randall has sat down with Olivier Hainaut, author of the study, to discuss the findings 👉 www.youtube.com/watch?v=LJNw... 🔭 🧪 ☄️ #DarkSkies 2/2

ESO@eso· Jul 2

How many satellites in Earth orbit is too many? 🚨 Since 2019, the number of satellites orbiting Earth has increased to over 14 000 today. Current proposals aim at adding 1.7 million more satellites in the future. The most extreme plans come from SpaceX & Reflect Orbital 👇 🔭 🧪 ☄️ #DarkSkies 1/2

ESO@eso· Jul 2

The so-called Running Chicken Nebula is revealed in spectacular detail in this 1.5-billion-pixel image. The brightest twinkle is Lambda Centauri, a star visible to the naked eye that is much closer to us than the nebula itself. 🔭

Wide-field astronomical image showing glowing clouds of pink, purple, and blue gas and dust stretch across the centre of the image, illuminated by young, bright stars embedded within the nebula. Smaller nebulae appear to the upper right and lower right, while dark dust lanes weave through the scene.

ESO@eso· Jul 2

Travel to the orange dwarf star PDS 70, located in the southern constellation of Centaurus. There, a young planet is forming, carving a path through the primordial disc of gas and dust around this very young star. 🔭 #exoplanets

ESO@eso· Jul 1

SpaceX & Reflect Orbital have filed with the US Federal Communications Commission for permission to launch. Our response to the FCC, with @royalastrosoc.bsky.social and the International Astronomical Union, was based on this study 👉 https://www.eso.org/public/news/eso2607/ 🔭 🧪 ☄️ #DarkSkies 4/4

ESO@eso· Jul 1

Reflect Orbital aims to launch 50,000 mirror-like satellites to provide sunlight at night, with reflected beams spanning at least 5 km on Earth's surface. This image illustrates how scattered sunlight would increase the overall brightness of the sky above the VLT. 🔭 🧪 ☄️ #DarkSkies 3/4

Two circles shows the night sky view from ESO's Very Large Telescope. The left image was captured with an all-sky camera on a moonless night. The image to the right is a simulation showing how much brighter the sky would be with Reflect Orbital’s full constellation of 50 000 mirrors. Even though the mirrors are not pointing directly at the observatory, they still diffuse light sideways, which is then further scattered by the atmosphere. The sky would be up to three to four times brighter.

ESO@eso· Jul 1

SpaceX plans to launch 1 million satellites for space-based data centres. This diagram shows the satellites that would be visible above our VLT: ⚪ invisible satellites in Earth’s shadow 🟠 2000 satellites brighter than magnitude 7 🔴 200 satellites brighter than magnitude 5 🔭 🧪 ☄️ #DarkSkies 2/4

A globe full of dots of various colours. The grey dots are satellites in the Earth’s shadow and therefore invisible. The coloured dots are illuminated satellites. The orange dots, almost 2000 of them, correspond to satellites brighter than magnitude 7 –– the faintest brightness visible to the naked eye from extremely dark locations. The red dots, more than 200, are satellites brighter than magnitude 5, which corresponds to the faintest objects visible to the naked eye from a suburban location.

ESO@eso· Jul 1

🚨 Beyond the limit 🚨 New ESO study finds that current proposals to launch 1.7+ million satellites into orbit would have devastating consequences for astronomy. The most extreme proposals come from SpaceX & Reflect Orbital 🔭 🧪 ☄️ #DarkSkies #SatelliteConstellations 1/4

Credit: F. Kamphues, ESO/M. Kornmesser. The background of this image shows a starry sky, including the bright lane of the Milky Way. Hundreds of bright streaks cross the sky in different directions, as if scratching the background natural sky behind it. The bottom of the image is occupied by the dark silhouette of a mountainous desert landscape. Atop the mountain at the centre, is a small, distant metallic dome and yellow-orange lasers shine behind it.

ESO@eso· Jun 30

This fisheye projection shows the Milky Way stretching across the sky, over the winding road leading through the La Silla Observatory. The ESO 3.6-metre telescope is visible reflected in a roadside mirror. 🔭 #flashback 📷 ESO/B. Tafreshi

Fisheye night-sky view from an observatory site, showing the Milky Way stretching across a star-filled sky

ESO@eso· Jun 29

It may look as though we’re about to enter the Milky Way. Yet this image features the road sign indicating the entrance to the ALMA observatory, co-operated by ESO & studying the coldest corners of the Universe. https://www.eso.org/public/images/potw2626a/ 🔭 🧪 📷 @julienlooten.bsky.social /ESO