14 INCREDIBLE GALAXIES
1 PRETTY PINWHEEL MESSIER 83
Messier 83 is a large, photogenic spiral galaxy with a bar-shaped centre. It sits 15 million light years away in the constellation of Hydra. Messier 83 is weird in a couple of ways. First, it appears to have a double nucleus at its centre – perhaps the mark of two supermassive black holes holding the galaxy together, or perhaps the effect of a lopsided disc of stars orbiting a single central black hole. Secondly, Messier 83 is a supernova supersite. Astronomers have directly observed six of these stellar explosions in the galaxy, along with remnants of 300 more. This puts Messier 83 in second place for supernovae – only the galaxy NGC 6946 has produced more observable stellar explosions, with nine.
2 TWO HEARTS NGC 7674
Most galaxies are likely to be anchored by a supermassive black hole at their centre. A few, however, contain not
