Gaia space observatory shows the Milky Way's stars dancing

Gaia is spacecraft sent by the European Space Agency (ESA) lauched in December 2013 in order to study star motions in our galaxy, the Milky Way.

Gaia spacecraft

In April, 2018 an important data release has been performed, including data of thousand of million of  stars detected by Gaia observatory. This data show not only positions but also velocities of 1.7 billion of stars.

Photo of the Milky Way taken from Mulato, Gran Canaria (astroGC)

Teresa Antoja, researcher at Barcelona university recently discovered an unexpected pattern within this stars. They are moving as the waves on the surface of water after a stone has been thrown.

According to this data, our galaxy suffered a near collision with a smaller galaxy in the last 300 or 1000 million of years. This could have been a close encounter with the Sagittarius dwarf galaxy, currently at 65 000 light years away from us. Sagittarius dwarf galaxy contains a few tens of million of stars and it is in the process of slowly being absorbed into the milky way.

More info about Gaia project: Gaia
More info about Teresa Antoja discovering: News from Gaia


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