Cosmic collisions.jpg

Cosmic collisions

DURING THE long dark winter nights, the Milky Way will be seen passing overhead. This pale band of light is actually our own galaxy seen from the inside. It is the combined light of more than two hundred thousand million stars.

During the early evening hours of December, the constellation of Andromeda will be in the zenith of the night sky, just alongside the Milky Way. This constellation is not that remarkable and contains no bright stars, but it does contain an object of special importance – the great galaxy of Andromeda.

This galaxy is very similar to our own but larger, containing around five hundred thousand million stars. Of course the stars of the Andromeda constellation belong to our own galaxy and are relatively close to us, but the Andromeda galaxy is approximately two million light years away. This object is visible without a telescope as a small patch of faint misty light about the size of your little fingernail at arm’s length. It won’t stay like that forever because this galaxy is heading in our direction at a speed of about three hundred thousand miles per hour! But not to worry – the collision will happen 2.5 billion years in the future.

The fact is that this is a good thing as galaxy collisions are common and our Milky Way galaxy has had many encounters in the past and the end result is that the union of two galaxies results in an exposition of new stars being born due to the mixing up of the dust and gas that lies between the original stars. In many respects, the life cycles of galaxies has an almost human side to it relying on a union of two to produce new life.