The Andromeda-Milky Way Collision

I found a pretty interesting article from NASA that discusses the cosmic collision of the Andromeda and Milky Way Galaxy. The event will occur billions of years into the future and give birth to new stars. Although the event is described as a collision, a cosmic merge is a more fitting term. According to NASA, this is not the end...

When Galaxies Collide
Let's look four billion years into the future. A group of our descendents stands with their teacher and looks up at a night sky ablaze with thousands of dazzling white stars. All of these new stars are being born, their teacher tells them, because of an immense cosmic event.

Our galaxy, the Milky Way, has collided with another galaxy, called Andromeda. Although the two galaxies are passing through each other at a million miles an hour, the whole process will take many millions of years to complete. And when everything settles down, the two galaxies will have merged into one.

The students fear that this may be the end of life, as they know it. But, their teacher reassures her class that there is very little chance of stars from the Andromeda galaxy hitting the Sun or the Earth. Even though the galaxies pass clear through each other, she says, stars in a galaxy are spaced very far apart.

They are like grains of sand separated by the length of a football field. The Andromeda stars simply pass by. But galaxies are more than just stars. They contain giant clouds of gas and dust. And, when galaxies collide, these clouds smash into one another. The clouds contain the raw materials needed to make new stars. It is the collision between clouds that has triggered a starry baby boom!
Source: NASA