ROBERT SIEGEL, host:
Astronomers have discovered an exploding star, a supernova, far brighter than any supernova ever seen before. It is in a galaxy far, far away. But they say that a star in our own galaxy could also explode in the same dazzling manner.
NPR's Richard Harris has the story.
RICHARD HARRIS: Astronomers are always patrolling the skies on the lookout for new supernovas. Last September, a grad student at the University of Texas hit pay dirt. He spotted a supernova explosion in a distant galaxy that has put all other supernovas to shame. Astronomers using the Lick Observatory in California, the Keck Telescope in Hawaii and the Chandra X-ray Observatory in orbit turned to watch the aftermath. Nathan Smith at UC Berkeley announced the results today at a NASA news conference.
Mr. NATHAN SMITH (Graduate Student, University of California, Berkeley): The reason we're so excited about it is that the supernova is so powerful it may require a new type of explosion mechanism that has been predicted theoretically but has never actually been observed before.
HARRIS: Regular supernova explosions are exciting enough. Generally when a star burns through its fuel its core collapses, the resulting explosions spews atoms and radiation all over space and leaves behind a cosmic cinder often a black hole. Smith says this new star apparently died a very different death.
Mr. SMITH: Instead of the core of the star collapsing, the core of the star is completely obliterated. It's just blast away all of its material out into space, and so all of these heavy elements - these radioactive elements - go spewing out to large distances where they can then heat the material and then glow and we can see the fabulous display that it puts on.
HARRIS: If this is what happened, it implies the original star was about a hundred times more massive than our own sun. That's really big and rare. Smith's colleague, David Pooley, says there are just a handful of stars that size in our own galaxy. And he has his eye on one called Eta Carinae.
Mr. DAVID POOLEY (Graduate Student, University of California, Berkeley): And a galactic supernova would be a spectacular event. It would be so bright that you would see it during the day and you could even read a book by its light at night.
HARRIS: In the middle of the 19th century, Eta Carinae erupted but didn't explode. The new supernova also erupted before it exploded about a decade ago. So Mario Livio, a theorist at the Space Telescope Science Institute, says Eta Carinae could well be heading toward the same spectacular end.
Dr. MARIO LIVIO (Astrophysicist, Space Telescope Science Institute): Now, this could happen tomorrow or it could happen a thousand years from now.
HARRIS: And if it did happen it would spew out an incredible amount of radiation. Should we be worried?
Dr. LIVIO: Life on earth can be affected if you have something like a gamma-ray burst. These very powerful explosions that produce gamma rays, and they have jets that are very collimated if the jet were to point directly at us it could have serious effect on our atmosphere and effect on life.
HARRIS: The good news is astronomers can see which way Eta Carinae is pointing, and is not pointing at us. So if it did suddenly start beaming radiation, well, that's someone else's problem.
Dr. LIVIO: So I think we can sleep quietly tonight. However, you know, this particular supernova and all the questions that it brings about, you know, will keep us awake for quite a while.
HARRIS: The tantalizing initial observations of the new supernova are being published in the Astrophysical Journal.
Richard Harris, NPR News, Washington.