The Satellite Gaia: Mapper of a Billion Stars

Gaia will be launched on 20 November to map our galaxy in 3D.

The Satellite Gaia: Mapper of a Billion Stars

During its five-year mission around our planet, the satellite Gaia will rotate slowly, pointing its two high-performance telescopes towards the farthest corners of the Milky Way and beyond. Tonight, for the first Mardi de l’espace (Space Tuesday) of the new season, join us and two experts from the CNES and the Paris Observatory. In person and online at #CNESTweetup, we’ll discuss this extraordinary project in the company of two astronomers, Catherine Turon, of the Paris Observatory, and Olivier La Marle, of France’s CNES. 

During its five-year mission around our planet, the satellite Gaia will rotate slowly, pointing its two high-performance telescopes towards the farthest corners of the Milky Way and beyond. Tonight, for the first Mardi de l’espace (Space Tuesday) of the new season, join us and two experts from the CNES and the Paris Observatory. In person and online at #CNESTweetup, we’ll discuss this extraordinary project in the company of two astronomers, Catherine Turon, of the Paris Observatory, and Olivier La Marle, of France’s CNES. 

Cet article existe également en français : GAIA : Le satellite cartographe d’un milliard d’étoiles

 
Artist’s impression of the satellite Gaia with its object of study behind: the Milky Way
Source: ESA/ATG media lab; background image: ESO/S. Brunier

Understanding better our galaxy’s past and predicting its future: that is the goal of the team behind the Gaia project. Thanks to the very precise measurements that the satellite will be able to make, not only will the distances be better known, but also the movements of the stars of our galaxy. Join the CNES, the Bar des Sciences and MyScienceWork tonight at 7:30 at the Café du Pont-Neuf in Paris to discuss the European mission Gaia. Two astronomers, Catherine Turon of the Paris Observatory and Olivier La Marle of the CNES, will present the mission and answer your questions.

“Gaia will push way back the limits of astrometry (the branch of astronomy that evaluates the position, distance and movement of celestial objects). The measurements collected will be 50 times more precise than its predecessor’s,” explains Catherine Turon who contributed greatly to the coordination of the French contribution to the project. “Gaia’s predecessor, the satellite Hipparcos, could take measurements from up to 500 light years away. Gaia, will be able to go up to 30,000 light years, with a margin of error of only 0.001%,” enthuses the recipient of the 1991 silver medal of the CNRS (France’s National Center for Scientific Research).

 
ESA model of how Gaia will scan the sky

Olivier La Marle, head of the astronomy program at the CNES is especially looking forward to this aspect of the Gaia adventure. “We’re used to seeing the Milky Way edge-on. Gaia’s 3D mapping will change our perspective and help us understand the distribution of different stars in the galaxy and how they move.”

Measurements highly anticipated by the international community

In parallel with the observation of the distances, Gaia will be able to analyze and measure the light and radiation coming from the stars, in order to characterize them from an astrophysics point of view. The potential applications of the satellite, therefore, go well beyond astrometry alone. The satellite will let us completely decipher the different populations of our galaxy, which will allow a much deeper understanding of the formation and evolution of the Milky Way. These measurements will help us understand how stars burn and to determine their age. Gaia will also serve as a lab to test general relativity. “Astronauts all over the world are eagerly awaiting these measurements,” explains Catherine Turon.

 Gaia puts on its solar protection before launch
Credit: Arianespace

France, at the heart of the project

In 1989, with Hipparcos, Europe became a pioneer in the domain of astrometry. With Gaia, the role of French scientists is brought to the fore. “We are one of the biggest contributors to the European effort for processing the data that will come to us from Gaia,” Olivier Le Marle remarks. French laboratories, in association with the CNES, have numerous responsibilities in the Data Processing and Analysis Consortium (DPAC). French scientists have also contributed significantly to establishing the scientific objectives and to the design of the instruments. The firm EADS Toulouse is also the project manager of the satellite’s construction.

The European collaboration that Gaia represents will make a huge leap possible in the interpretation of the functioning of the galaxy. While we wait for Gaia to take off aboard a Soyuz rocket in November, the CNES, in partnership with the Bar des Sciences and MyScienceWork, invites you to the Café du Pont Neuf tonight at 7:30 for a special Mardi de l’Espace featuring Gaia. (Hashtag: #CNESTweetup)

 

To find out more:

Gaia: The 'impossible space mission' ready to fly

An explanatory site by Catherine Turon and her colleagues at the Paris Observatory (in French)