The Sky at Night - The Grand Collision

In two billion years' time our own Milky Way will collide with another galaxy, Andromeda. This cataclysmic event will rip apart the fabric of both galaxies, destroying stars and planets and sparking a shockwave of fiery rebirth. Eventually it will create new stars, solar systems and planets. Sir Patrick Moore anticipates this far-off event and explains the role that dark matter will play in this cosmic collision.