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Liftoff for Gaia

19 December 2013

Gaia will create the most accurate map yet of the Milky Way. By making accurate measurements of the positions and motions of one billion stars, it will answer questions about the origin and evolution of our Galaxy.

Gaia is now en route towards an orbit around a virtual point in space called L2, some 1.5 million kilometres beyond Earth as seen from the Sun.

Gaia spacecraft
Repeatedly scanning the sky, Gaia will observe each of the billion stars an average of 70 times each over the five years. It will measure the position and key physical properties of each star, including its brightness, temperature and chemical composition.

The motions of the stars can be put into ‘rewind’ to learn more about where they came from and how the Milky Way was assembled over billions of years from the merging of smaller galaxies, and into ‘fast forward’ to learn more about its ultimate fate.

By comparing its repeated scans of the sky, Gaia will also discover tens of thousands of supernovas, the death cries of stars as they reach the end of their lives and explode. And slight periodic wobbles in the positions of some stars should reveal the presence of planets in orbit around them, as they tug the stars from side to side.

Gaia will also uncover new asteroids in our Solar System and refine the orbits of those already known, and will make precise tests of Einstein’s famous theory of General Relativity.
