peter nugent of the lawrence- berkeley national lab discovered the supernova and joins us now. well, welcome to you. so, we're seeing this now but it happened rather a long time ago, in fact, right? >> yes, when something is 21 million light years away, that means it's taken 21 million years for that light to get to us. so it has been a long, long time ago in a galaxy far away. >> brown: and what is "it." remind us of what a supernova is. >> so the supernova that we're looking at here is the death of a star. supernova comes in all varieties and shape from stars that blow up that are ten, 100 times bigger than our son, but in one actually is a star called a carbon oxygen white dwarf which is about the size of the planet earth. >> brown: and what, they this one so remarkable? >> well, this supernova is incredible because we caught it so early and it's going to get so bright that astronomers will be able to use almost any of the telescopes on any of the major observatorys in the world to look at it. this supernova is also one of the supernova that we use to measure distances to ot