A new supernova??

Via Space.com, NASA has detected a mystery explosion only 440 million light years away that might signal the beginning of a new supernova. NASA Detects 'Totally New' Mystery Explosion Nearby

Astronomers have detected a new type of cosmic outburst that they can't yet explain. The event was very close to our galaxy, they said.

The eruption might portend an even brighter event to come, a supernova.

It was spotted by NASA's Swift telescope and is being monitored by other telescopes around the world as scientists wait to see what will happen.

Neil Gehrels, principal investigator for the Swift mission at NASA's Goddard Space Flight Center, called the event "totally new, totally unexpected."

If the eruption indeed precedes a supernova, then it would reach peak brightness in about a week, scientists said.

The event, detected Feb. 18, looks something like a gamma-ray burst (GRB), scientists said. But it is much closer—about 440 million light-years away—than others. And it lasted about 33 minutes. Most GRBs are billions of light-years away and last less than a second or just a few seconds.

Other aspects of the newfound eruption were inexplicable, astronomers said. It was dimmer than most. Even so, the newly spotted point of light in the sky outshines the entire galaxy in which the event occurred.

Fascinating. If it's not a supernova, what is it?