Gaia's latest survey of our galaxy
The impact of the astrometry satellite Gaia on astronomical research is enormous: on average, around five scientific papers based at least in part on the results of ESA's Gaia mission are published around the world every day. Now, on December 3, 2020, the first part of the third Gaia star catalog has been published - with even more stars and even more precise data.
On December 19, 2013, the European Space Agency ESA launched the Gaia astrometry satellite. Since then, the Gaia instruments have been measuring data from stars with great precision, including their position, proper motion, distance, brightness and color. In 2018, Gaia's second star catalog, Gaia Data Release 2 (DR2), was released, containing the measurements of 1.3 billion stars. Practically all areas of astrophysics have already benefited from this data. Above all, our picture of the history of the formation and development of the Milky Way system has been significantly enriched by the Gaia data. For example, we now know that the Milky Way's thick disc and inner halo were only formed by a collision with another galaxy (dubbed Gaia-Enceladus) about ten billion years ago.
Other interactions of our galaxy with small dwarf galaxies have also left their traces in Gaia's position and motion data of the stars. There is even evidence that the birth of our sun was caused, among other things, by an increased rate of star formation during the last close encounter with the Sagittarius dwarf galaxy. And finally, we now know much more precisely how much the Milky Way plane was bent, probably also by the Sagittarius galaxy.