Using the Gaia Space Telescope, researchers from the Canary Islands Astrophysics Institute have gained valuable clues about the formation of our galaxy. They confirm that a collision occurred 10 billion years ago between the Milky Way and the dwarf galaxy, Gaia-Enceladus.
If astronomers already thought that our Galaxy was composed of two distinct sets of stars, they could not find out when and how they had merged.
A collision 10 billion years ago
Researchers at the Canary Islands Institute of Astrophysics think they have discovered how the Milky Way was formed. Thanks to the Gaia space telescope, they found clues of the first steps in the history of our Galaxy.
Indeed, the satellite allowed them to take precise measurements concerning the position, brightness, and distance of about a million stars. It then appeared to them that a dwarf galaxy, Gaia-Enceladus, had collided with the Milky Way 10 billion years ago.
Space cannibalism
To arrive at this conclusion, the researchers studied the density of the elements without hydrogen or helium of these stars. They then observed two sets of distinct stars, of about the same age. However, one of the two was put into chaotic motion, indicating a galactic collision.
After the collision, the Milky Way would have consumed the dwarf galaxy for millions of years, contributing to the formation of new stars over a period of four billion years. Astronomers also think that the halo of the Milky Way is from the remains of this dwarf galaxy.
The cannibalism is a process "common in space. For example, our neighbor, the Andromeda galaxy, cannibalized a nearby galaxy about two billion years ago. And in the very distant future, it will collide with our ...
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