NASA-International Space Station

Astronomers have revealed a new kind of cosmic explosion that seems to have originated from an extremely massive star one that's over 200 times the size of our own sun.

Scientists first discovered SN2007bi, the supernova in question, in 2007, and were instantly puzzled. It finally faded just recently. "It was much brighter, and it was bright for an extremely long time," said researcher Paolo Mazzali, of the Max-Planck Institute for Astrophysics in Germany, in the report. "We could watch this thing almost two years after it was discovered, where you normally don't see anything anymore."

The resultant explosion was about 50 to 100 times brighter than a distinctive supernova and rewrites what astronomers knew about star formation. 2N2007bi has turned out to be a pair-instability supernova, which releases protons so vigorous that they generate pairs of electrons and their anti-matter opposites, positrons, the report said. The two meet, eradicate each other, and cause the star itself to collapse, "igniting its oxygen core in a runaway nuclear explosion that eats up the whole star."