Galactic Whirlpools

In the depths of space there are giant tornadoes of cold, dusty gas and galactic whirlpools containing thousands of millions of stars. Patrick Moore is joined by Professor Chris Kitchin to discuss how these helices of the heavens are formed and to predict the fate of our own spiral galaxy, the Milky Way, when it collides with the Andromeda galaxy in 3,000 million years time.