The Gaia Space Telescope presented its new data on nearly two billion stars in the Milky Way on Monday, with astonishing accuracy that makes it possible to map a galaxy teeming with life.
Presenting the results of the Gaia telescope, one of the agency’s flagship missions launched in 2013, ESA Director-General Josef Asbacher said: “It’s a wonderful day for astronomy, and opens the door to new discoveries about the universe and our galaxy.”
This is the third data-collection mission undertaken by the space observatory, which is stationed 1.5 million kilometers from Earth versus the Sun, and aims to map our galaxy in all its dimensions, and thus understand its origin, structure and dynamics.
Equipped with two telescopes and a photographic sensor with a resolution of a billion pixels, Gaia’s mission is scanning a tiny fraction, not more than 1%, of the stars in our galaxy 100,000 light-years across, and even further away.
And the numbers revealed on Monday were astonishing: by analyzing data sent to Earth, over a period of 34 months, Gaia was able to provide information about more than 1.8 billion stars.
The mission provides an unprecedented set of detail, including 220 million spectra of spectra, which will make it possible for the first time to estimate the mass, colour, temperature and age of stars. It also introduces 2.5 million new chemical structures, DNA that tells us where stars are born, and their journey through the galaxy.
Gaia also provides data on 35 million radial velocities, measuring their transmission and providing a new understanding of motions in the Milky Way.
The biggest surprise is that Gaia has observed for the first time stellar “tremors”, which are small movements on the surface of a star that change its shape. This discovery opens up a “gold mine for stellar science at the scale of massive stars”, that is, their inner workings, explained Connie Aerts of the University of Louvain in Belgium, a collaborating member of the Gaia mission.
The scientific director of the Gaia mission in France, François Minniard, says that this mission “goes beyond expectations on all levels.”
The astronomer from the Observatory of the French coastal Côte d’Azur told AFP that the results that contributed to writing about fifty scientific articles paint a picture of a galaxy “more turbulent” than expected.
“We thought it had come to a standstill,” he says, “turning gently on itself, like a liquid being stirred softly with a wooden spoon. But it’s not at all like that!” Her life is “full of accidents and unexpected moves, and it’s not that simple.”
For example, our solar system “does not just rotate in a vertical plane, it rises and falls up and down”, says François Miniar.
Our solar system is home to a heterogeneous group of stars, some of which did not exist from the start but may have been “swallowed” along the way, through interactions with the nearby dwarf galaxy Sagittarius.
“Our galaxy is a wonderful melting pot of stars,” says Alejandra Recio Blanco of the Côte d’Azur Observatory.
Anthony Brown, president of the international consortium DBAC that makes up the ground-processing chain of the data stream sent from the Gaia mission, explains that the mission’s level of accuracy “will allow us to trace the past of the Milky Way over more than 10 billion years.”
Stars have the property of being able to live billions of years, as astronomers point out that their measurement is like a fossil that tells us about the state of the galaxy during its formation.
With the second measurement record delivered in 2018, the researchers were able to show that our galaxy had “merged” with another 10 billion years ago.
The new record provides unparalleled precision measurements of the 156,000 asteroids in our solar system, by breaking apart the composition of 60,000 of them.
It took five years to deliver this third record of observations spanning from 2014 to 2017.
We’ll have to wait until 2030 for the final version, when the Gaia mission will finish its space survey in 2025.
(AFP)