The Gaia telescope reveals the final secrets of the turbulent Milky Way

It’s a fantastic day for astronomy, opening the floodgates to new discoveries about the universe and our galaxy.said Josef Aschbacher, Director General of the European Space Agency (ESA) while presenting the results of Gaia, one of the agency’s flagship science missions launched in 2013.

Stationed 1.5 million kilometers from Earth, opposite the Sun, the space observatory is in its third data harvest, designed to map our galaxy in all its dimensions and thus understand its origin, structure and dynamics.

Equipped with two telescopes and a billion-pixel photo sensor, Gaia is scanning a very small fraction (just under 1%) of the stars in our galaxy, which are 100,000 light-years across.

The figures presented on Monday are incredible: By analyzing the 700 million data sent to Earth every day for 34 months, Gaia was able to provide information on more than 1.8 billion stars.

A wealth of unprecedented detail is provided, such as these 220 million photometric spectra, making it possible for the first time to estimate the mass, colour, temperature and age of stars. And 2.5 million new chemistries, this DNS Providing information about the birthplace of the stars and their journey through the galaxy.

Or 35 million radial velocities measuring the displacement of stars and offering a new understanding of the Milky Way’s movements.

Surprise for scientists: Gaia sighted for the first time Tremble stellar, tiny movements on a star’s surface that change its shape. Discovery opens a goldmine for asteroseismology of massive starsnamely their inner workings, explained Conny Aerts from the University of Leuven, Belgium, member of the Gaia collaboration.

On all levels, Gaia exceeds expectationswelcomed François Mignard, scientific director of the Gaia mission to France, at Agence France-Presse (AFP).

The results, which have led to around fifty scientific articles, paint a portrait of a galaxy much more turbulent than expected, the astronomer from the Observatory of the Côte d’Azur told the AFP news agency.

It was believed to have reached a steady state and gently swirled around, like a liquid being gently stirred with a wooden spoon. Not at all ! explains Francois Mignard.

On the contrary, her eventful life is composed of coincidences, of unexpected movements and not as simple as this spiral that she describes. For example, our solar system “rotates not only in a vertical plane; it goes up and down, up and downsays François Mignard.

It’s also home to a very heterogeneous population of stars, some of which weren’t there to begin with, but may have been swallowed en route through interactions with the nearby Sagittarius dwarf galaxy.

Our galaxy is a beautiful melting pot of starssummarizes Alejandra Recio-Blanco from the Observatory of the Côte d’Azur.

Gaia’s level of precision is such that it will allow us to trace the history of the Milky Way for more than 10 billion yearsadded Anthony Brown, president of the international consortium DPAC, the ground processing chain for the data flow sent from Gaia.

Stars have the peculiarity of living for billions of years: analyzing them is equivalent to examining a fossil, which tells us about the state of the galaxy during its formation, astronomers point out.

With the second catalog, delivered in 2018, astronomers were able to show that our galaxy had merged with another 10 billion years.

The new catalog also offers measurements of unprecedented precision for 156,000 asteroids in our solar system, dissecting the composition of 60,000 of them.

It will have taken five years to deliver this third catalog of observations, spread from 2014 to 2017. And we’ll have to wait until 2030 to get the final version, when Gaia will have finished scanning space in 2025.

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