How Did The Milky Way Form?

Astronomers aren't sure how the first galaxies came to be because it's hard to see what the universe was like when it was young.

In the modern universe, there are places with a lot of matter, like galaxies, and places with very little matter, like the space between galaxies.

The Milky Way probably started out like every other galaxy: as a small clump of matter that was slightly denser than the average in the universe.

This clump was almost entirely made of dark matter, a type of matter that does not interact with light.

Around 12 billion years ago, when the first clumps of dark matter and their groups of stars came together, they made the proto-Milky Way.

Once that happened, the Milky Way became a separate part of the universe, separate from what was around it.

Its tremendous gravity dragged in an increasing amount of dark matter and gas, which resulted in the rapid acceleration of its growth.

The Milky Way is tearing apart its own satellites, the Large and Small Magellanic Clouds. This is happening right now.

NASA says, though, that the Milky Way is headed for a collision with its biggest neighbour, the Andromeda galaxy.