Something’s going on up there. SPACE.com actually says it’s a good idea to watch the skies “just in case” Betelgeuse is about to blow up:
Betelgeuse, a reddish star that’s one of the brightest in the night sky, has been noticeably “fainting,” or getting dimmer. The approximately 8.5 million-year-old star, which is part of the Orion constellation, has been one of the most recognizable stars in the sky because of its brightness and coloration. But this recent, dramatic fading has prompted scientists to suggest that the star might be entering a pre-supernova phase, dimming before it collapses and “dies” in a fiery supernova explosion.
If the star does become a supernova, Betelgeuse would likely be as bright as, or even brighter than the moon for weeks or even more.
At 642.5 light-years from Earth, it would be the closest supernova observed and recorded by humans (closer than the Crab Nebula, which is 6,523 light-years from Earth and is the result of a supernova reported to have taken place in A.D.1054).
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It’s not surprising that the extremely massive star (which is likely about 20 times the mass of the sun) has been dimming, because it’s a variable star — meaning its brightness naturally shifts, something that scientists have observed for decades.
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While it’s possible that the star could explode anytime between now and 100,000 years from now, this dimming might not actually be a sign that it’s about to blow, both [UC Berkeley stellar explosions researcher Sarafina] Nance and [Villanova University astrophysics professor Edward] Guinan said.
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While he acknowledges that it could explode soon and this dimming could be a sign that that explosion may happen relatively soon, “I believe it isn’t going to blow up now,” Guinan said. “I hope it does, but my bet is that it’s not going to, it’s gonna come back up [get brighter] again.”
Nance admits that “we could absolutely be wrong,” she said, referring to her theory that the dimming is not a sign that the star is about to explode. That said, “I do think that this is more indicative of really interesting physics that’s going on with the star rather than an imminent explosion.”
“If it does explode and we’re wrong, awesome — I would love to be wrong, I would love to see that,” Nance said.
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According to Nance, while no one is exactly sure why this stellar fainting is happening, it could be caused by instabilities within Betelgeuse. She explained that different parts of stars can have different densities, and this density instability can cause energy to rise and fall within a star, moving energy from its inside to its outside. This, in turn, and can cause changes in brightness, cause the star to get bigger, to contract and much more.
Nance added that this extreme dip in brightness could also be attributed to magnetic activity on the star, but it is difficult to model that activity through simulations, so they do not yet know if that is a definite factor. She even added that it’s possible that matter ejected from the star is creating “a sort of dust fog” that’s currently obscuring and “dimming” the star.