From supernaovae (Image 1), stars begin their life as clouds of nebulus gas and dust remnants left over from these great explosions (Image 2). These gas clouds accrete and bond together to form a rotaing disc. Heavier material tends to travel inward as mass increases in the centre of the disc (Image 3). Immense pressures are created as gravity forces more and more matter together until even the bonds between individual atoms are broken down. Nuclear fusion takes place and a star is born (Image 4).