The Gaia space probe unveiled its latest discoveries Monday in its quest related to the Milky Way’s secrets in unprecedented detail, surveying nearly two million stars and revealing mysterious “starquakes” that sweep away the fiery giants like great tsunamis.
The third set of data from the mission, which will be delivered to 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 isn’t a single astronomer who doesn’t 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 catalog of more than 156,000 asteroids in our Solar System “whose orbits the instrument has calculated with unparalleled precision,” Mignard said.
But Gaia also sees beyond the Milky Way, detecting 2.9 million other galaxies, as well as 1.9 million quasars, the incredibly bright hearts of galaxies powered by supermassive black holes.
The Gaia spacecraft is in a strategically placed orbit 1.5 million kilometers (937,000 miles) from Earth, from where it has been observing the skies since it was launched by 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 about one percent of the stars in the Milky Way, which is about 100,000 light-years across.
The probe is equipped with two telescopes and a billion-pixel camera, which captures images sharp enough to measure the diameter of a human hair at a distance of 1,000 kilometers. It also has a range of other instruments that allow it to not only map the stars, but also measure their motions, chemical compositions, and ages.
“It provides a global look at the positions of anything moving 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 enormous variety 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 the formation of our galaxy,” he said. “It also clearly shows that our Sun, and us, all belong to a constantly changing system, formed thanks to the assembly of stars and gas of different origins.”