GAIA (Global Astrometric Interferometer for Astrophysics) is a European Space Agency (ESA) mission to study the structure, origin, and evolution of our galaxy.
GAIA is an astrometric satellite that aims to make extremely accurate measurements of the positions, distances, motions, and other properties of stars and other celestial objects in our Milky Way galaxy and beyond.
Examples of what GAIA aims to achieve include:
- Measure the positions and distances of over one billion stars in the Milky Way with an accuracy of a few microarcseconds.
- Measure the positions and distances of thousands of quasars beyond the Milky Way.
- Measure the motions of stars in the Milky Way with an accuracy of a few microarcseconds per year.
- Measure the properties (temperatures, masses, ages, etc.) of over a hundred million stars.
- Discover thousands of new celestial objects, such as asteroids and comets in our Solar System, exoplanets, and brown dwarfs.
It was launched in December 2013 and is still operational, it is expected to provide data until the mid 2020s.