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Astronomers are carefully watching a nearby star. It's been behaving very strangely over the past few weeks. And as NPR's Geoff Brumfiel reports, stargazers don't even need a telescope to witness its remarkable change.
GEOFF BRUMFIEL, BYLINE: Look up at the constellation Orion, and there it is. It's one of the shoulders, and it's usually one of the brightest stars in the sky. It's called Betelgeuse. Edward Guinan has been watching Betelgeuse since Ronald Reagan was president.
EDWARD GUINAN: 1981.
BRUMFIEL: 1981 - do you feel like you have a relationship with Betelgeuse at this point?
GUINAN: Yeah, I do (laughter). It's my star.
BRUMFIEL: Guinan has been keeping an eye on it from his perch at Villanova University, where he's a professor of astrophysics. It's not the only star he looks at, but it's definitely his favorite.
GUINAN: A lot of stars I actually study that I pretty well know what they're going to do. It's Betelgeuse I don't know. No, I don't, so it's a puzzle to me. You know, I like puzzles.
BRUMFIEL: Unlike other stars, Betelgeuse brightens and fades unpredictably. And starting late last year, Guinan and his colleague noticed something. Betelgeuse just kept getting dimmer and dimmer.
GUINAN: It kept getting fainter and beyond where we ever observed it. We never observed it this faint.
BRUMFIEL: Emily Levesque is an astronomer at the University of Washington. She says the star has become so faded, at this point, anyone can walk outside and see for themselves.
EMILY LEVESQUE: It's very obviously dimmer than the star that would be in one of Orion's knees, which is Rigel. It does jump out to a stargazer that the constellation really looks different.
BRUMFIEL: It looks so different that some have speculated Betelgeuse may be on the verge of a violent death. Unlike our sun, which will burn for billions of years, Betelgeuse's lifespan is around just 10 million years. It's what's known as a red supergiant, a roiling, boiling star, constantly pulsing and changing.
LEVESQUE: It's kind of this live-fast-die-young version of stellar evolution.
BRUMFIEL: Levesque says part of the reason astronomers are taking such an interest is that if Betelgeuse is about to die, it won't just fade away. It will collapse and then explode in a huge, spectacular supernova. Here on Earth, we'd get quite a show.
LEVESQUE: You'd see it in the daytime sky for weeks. At night, I believe it would be comparable in brightness to the full moon or something close to that. I mean, you'd be able to see a shadow cast by the brightness of this supernova.
BRUMFIEL: So is it about to blow? Well, there are some other possibilities. Maybe the star just belched out some dust that's blocking our view, at least for now. And the truth is stars live and die on their own timescales, not ours.
LEVESQUE: It could be getting ready to go supernova very soon, but very soon could mean another 10,000 years or 100,000 years.
BRUMFIEL: So maybe don't hold your breath. But if you're out and it's dark and you can see Orion, you might just want to keep an eye on Betelgeuse.
Geoff Brumfiel, NPR News.
(SOUNDBITE OF ULRICH SCHNAUSS' "KNUDDELMAUS") Transcript provided by NPR, Copyright NPR.
