Supernova in M51
On June 2nd 2011, French astronomers spotted what appeared to be a supernova (exploding star) in the Whirlpool Galaxy.
This was confirmed as Type II supernova. A supernova is when a star collapses and explodes, and can briefly outshine a whole galaxy, as the star core blows off most of the stars mass.
Without supernova, there would be no life in the Universe. As the star collapses, it creates heavier elements as it tries to resist the force of gravity, elements such as carbon, iron, etc.