The European Space Agency’s Gaia space probe has revealed its most astonishing discoveries yet, releasing a vast new trove of data that promises to transform our understanding of the Milky Way. The mission’s third major data set, published on Monday at 10:00 GMT, charts nearly two million stars and captures extraordinary phenomena such as enormous “starquakes” rippling across distant stellar giants.
ESA hailed the release as a milestone that “revolutionises our understanding of the galaxy.”
ESA’s Gaia mission unveils stunning new data, including “starquakes”, millions of galaxies, and the most detailed stellar survey ever completed.
The European Space Agency’s Gaia space probe has revealed its most astonishing discoveries yet, releasing a vast new trove of data that promises to transform our understanding of the Milky Way. The mission’s third major data set, published on Monday at 10:00 GMT, charts nearly two million stars and captures extraordinary phenomena such as enormous “starquakes” rippling across distant stellar giants.
ESA hailed the release as a milestone that “revolutionises our understanding of the galaxy.”
Table of Contents
“The Swiss Army Knife of Astrophysics”
“Gaia is the Swiss Army knife of astrophysics — there is not a single astronomer who does not use its data, directly or indirectly,” said François Mignard, a member of the Gaia science team.
The newly released map includes insights close to home: a catalogue of more than 156,000 asteroids within our Solar System, with their orbits determined with unprecedented precision.
But Gaia’s reach extends far beyond the Milky Way, detecting 2.9 million neighbouring galaxies and 1.9 million quasars, the ultra-bright centres of galaxies powered by supermassive black holes.
A Spacecraft with a Billion-Pixel Eye
Launched in 2013, Gaia circles the Sun in a stable orbit 1.5 million kilometres from Earth. From this vantage point, it scans the sky continuously using:
Two advanced telescopes
A billion-pixel camera, capable of detecting the width of a human hair from 1,000 kilometres away
Instruments that measure each star’s position, motion, composition, and age
“Gaia scans the sky and picks up everything it sees,” said Misha Haywood of the Paris Observatory. Yet even with its remarkable technology, the spacecraft can observe barely one per cent of the Milky Way’s stars — a galaxy roughly 100,000 light years across.
Before Gaia, Haywood said, astronomers had only a “restricted view” of the galaxy’s true structure.
A “Beautiful Melting Pot” of Stellar Diversity
Gaia’s new dataset highlights the immense diversity of stars in the Milky Way.
“Our galaxy is a beautiful melting pot of stars,” said Gaia scientist Alejandra Recio-Blanco. “This diversity is crucial because it reveals the story of how our galaxy formed. It shows that our Sun — and all of us — are part of an ever-evolving system built from stars and gas of many different origins.”
A Surprise Discovery: ‘Starquakes’
Among Gaia’s most unexpected findings is the observation of “starquakes” — powerful vibrations that alter the shape of stars.
The phenomenon was detected across thousands of stars, including types that should not experience such quakes according to existing scientific theories.
“Gaia is opening a gold mine for the asteroseismology of massive stars,” said Conny Aerts, a member of the Gaia team.
A Scientific Treasure: Thousands of Papers and Counting
Around 50 scientific papers were published alongside the new data release, with more expected in the years ahead. Since Gaia’s first data release in 2016, its observations have fuelled thousands of studies.
The second major release, in 2018, enabled astronomers to discover that the Milky Way merged with another large galaxy roughly 10 billion years ago in a violent cosmic collision.
An Enormous Data Effort
Gaia generates vast amounts of raw information every day:
700 million stellar positions
150 million photometric measurements
Processing this torrent requires a dedicated team of 450 European scientists and software engineers, six supercomputers, and extensive human analysis.
“Without this processing group, there is no mission,” said Mignard. “Gaia’s data must be interpreted — it doesn’t come ready-made.”
It took five years to assemble and refine the latest dataset, covering observations made between 2014 and 2017.
Gaia will continue scanning the cosmos until 2025, with its final and most comprehensive data release scheduled for 2030. “We cannot wait for the astronomy community to dive into our new data and discover even more about our galaxy and its surroundings than we ever imagined,” said Timo Prusti, ESA’s Gaia project scientist.