Typically, a Supernova (life ending explosions of stars) occur every 25 to 100 years per galaxy. In the past six weeks, astronomers using NASA's Swift* satellite have discovered two supernovas in the same galaxy. The galaxy, MCG +05-43-16, lies in the constellation Hercules at distance of 380 million light-years away.
The first, Supernova 2007ck was a Type II event. These events occur when a star runs out of fuel, collapses gravitationally upon itself, and then repels the collapse by exploding outwards. The second, Supernova 2007co was a Type 1a Supernova. Type 1a supernovas are when a white dwarf receives so much material from a nearby star that it triggers a huge bomb-like explosion.
These two supernovas occurred a mere 16 days apart - an occurrence very rare in astronomy.
* NASA's Swift satellite is mainly used to study Gamma-Ray Bursts, but for this event, the Swift Satellite used and Ultraviolet/Optical telescope to photograph the event.
Original Article: Goddard Space Flight Center