Comparison between Gaia’s first and second data releases

A virtual journey, from our Solar System through our Milky Way Galaxy, based on data from the first (left) and second (right) release of ESA’s Gaia satellite. The journey starts by looking back at the Sun, moving away and travelling between the stars.

A comparison between the two views shows the huge increase in number of stars and distances from the Sun between the two data releases.

The view on the left is based on the 3D position of 1.4 million stars for which parallaxes had been estimated using the Tycho-Gaia astrometric solution (TGAS) as part of the first Gaia data release, published in 2016.

The view on the right is based on the 3D position of nearly 97 million stars from the second data release, published in 2018. The majority of these stars have the most accurate parallax measurements in the dataset, which can be used to directly estimate distances to individual stars. 

Acknowledgement: Gaia Data Processing and Analysis Consortium (DPAC); Gaia Sky; S. Jordan / T. Sagristà, Astronomisches Rechen-Institut, Zentrum für Astronomie der Universität Heidelberg, Germany