J-P METSAVAINIO / SCIENCE PHOTO LIBRARY J-P METSAVAINIO / SCIENCE PHOTO LIBRARY
Supernova remnant Cassiopeia A. This is the remains of a star that exploded 325 years ago. When a large star dies, gas shells explode outwards and collide with interstellar material. The energy of the collision ionises the gas, causing it to glow. Cassiopeia A lies around 10,000 light years from Earth in the constellation Cassiopeia. Different colours represent different ionised gases; sulphur is red, hydrogen is green and oxygen is blue.
Model release not required. Property release not required.