Supernovae in the Whirlpool.

Where do spiral galaxies keep their supernovae? Near their massive star forming regions, of course , and those regions tend to lie along sweeping blue spiral arms. Because massive stars are very short-lived , they don't have a chance to wander far from their birth place. Remarkably, in the last 6 years two Type II supernovae , representing the death explosions of massive stars, have been detected in nearby spiral M51 . Along with a third supernova seen in 1994, that amounts to a supernova bonanza for a single galaxy. As demonstrated in these comparison images, SN2005cs, the supernova discovered in 2005, and more recently SN2011dh , the exceptionally bright supernova first recorded just last month, both lie along M51's grand spiral arms. Perhaps the original spiral nebula, M51 is also known as the Whirlpool Galaxy .