It is a 2.3-meter wide satellite linked to a circular sunshield and fitted with two telescopes as well as a 1-billion-pixel camera. Each day, Gaia sends 20-100GB of data to Earth.
How does Gaia work?
Gaia is positioned in space and orbits the sun in sync with our planet. It collects data about a star's composition by using spectroscopy.
Gaia also helps find age of a star
New stars have a higher percentage of heavy elements. Hence, by studying their composition, Gaia also helps in ascertaining the age of a star.
Mapping the Milky Way
By seeing which regions have stars with higher/lower metallicity, scientists can map out the Milky Way's evolution over time. Gaia will be operational until 2025.