PARIS: The Gaia space probe unveiled its latest discoveries on Monday in its quest to map the Milky Way in unprecedented detail, surveying nearly two million stars and revealing mysterious “starquakes” which sweep across the fiery giants like vast tsunamis.

The mission’s third data set, which will be released to eagerly waiting astronomers around the world at 1000 GMT, “revolutionises our understanding of the galaxy,” the European Space Agency (ESA) said.

“It’s the Swiss Army knife of astrophysics — there is not a single astronomer who does not use its data, directly or indirectly,” said Francois Mignard, a member of the Gaia team.

Some of the map’s new insights are close to home, such as a catalogue of more than 156,000 asteroids in our Solar System “whose orbits the instrument has calculated with incomparable precision,” Mignard said.

But Gaia also sees beyond the Milky Way, spotting 2.9 million other galaxies as well as 1.9 million quasars — the stunningly bright hearts of galaxies powered by supermassive black holes.

The Gaia spacecraft is nestled in a strategically positioned orbit 1.5 million kilometres (937,000 miles) from Earth, where it has been watching the skies since it was launched by the ESA in 2013.

“Gaia scans the sky and picks up everything it sees,” said astronomer Misha Haywood of the Paris Observatory. But it can still only detect around one percent of the stars in the Milky Way, which is about 100,000 light years across.

The probe is equipped with two telescopes as well as a billion-pixel camera, which captures images sharp enough to gauge the diameter of a human hair at a distance of 1,000 kilometres. It also has a range of other instruments that allow it to not just map the stars, but measure their movements, chemical compositions and ages.

“It provides a global observation of the positions of anything that moves in the sky, for the first time,” Haywood said, adding that before Gaia “we had a really restricted view of the galaxy”. It also reveals the huge array of differences between stars.

“Our galaxy is a beautiful melting pot of stars,” said Gaia member Alejandra Recio-Blanco.

“This diversity is extremely important, because it tells us the story of our galaxy’s formation,” he said. “It also clearly shows that our Sun, and we, all belong to an ever-changing system, formed thanks to the assembly of stars and gas of different origins.”

Published in Dawn,June 14th, 2022