It was a relatively recent supernova remnant - in the Milky Way, but a long way from here.
From Wired: NASA Announcement of "Success of Long Galactic Hunt".
Scientists using a combination of radio and x-rays have found the most recent supernova remnant observed in our galaxy, located about 26,000 light years from here. It's the youngest, most energetic supernova we know and could shed light on just exactly how the stardust we're made of -- heavier elements and all-- gets created. The finding also lends some support to astronomers calculations that there should be about three supernovae in our galaxy per century, although they still need to find dozens more similar supernova remnants to confirm their suspicions.
Talk about not living up to the hype...
