Supernova explosion. Artwork showing a supernova explosion which will lead to the formation of a new star. Shock waves are seen originating from the site of the explosion; these in turn will trigger the gravitational collapse of surrounding interstellar clouds of gas and dust, the first stage in the life of a star and eventually of a planetary system around the newborn star. Supernova explosions characterise the end of the life of massive stars. The outer layers of the star are violently ejected into space and at the core of the explosion an object such as a neutron star or a black hole may be found.