12 Million Years Ago a Star Exploded. 3 Days Ago Earth Saw this Supernova in M82

12 Million Years Ago a Star Exploded. 3 Days Ago London Saw the Supernova In A Telescope.

The supernova in M 82

Credit: UCL/University of London Observatory/Steve Fossey/Ben Cooke/Guy Pollack/Matthew Wilde/Thomas Wright

Supernova: stellar explosion that is more energetic than a nova

UCL: At 7:20 GMT on January 21st, 2014, students at the University of London "spotted one of the closest supernova to Earth in recent decades." This explosion occurred in galaxy Messier 82 (the Cigar Galaxy).

Source: Hubblesite.org

Space.Com: "...about 12 million light-years away in the constellation Ursa Major, or the Great Bear. ...One astronomer described as a potential "Holy Grail" for scientists"

Supernova 'Animated' on Space.com

Other nearby stellar explosions:

1. Supernova 1987A, spotted February 1987 in Large Magellanic Cloud, dwarf galaxy companion of Milky Way ~168,000 light years from Earth. 
2. Supernova 1993J in Messier 81 in 1993