Betelgeuse Will Eventually Explode as a Supernova Bright Enough to See by Day

Betelgeuse, a red supergiant in Orion, will eventually explode as a supernova bright enough to see by day for months, but it will not harm Earth.

Astronomy

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Betelgeuse is one of the most familiar bright stars in the constellation Orion and one of the closest red supergiants to Earth. Astronomers expect the aging star to eventually end its life in a supernova, an enormous stellar explosion that can briefly make a star extraordinarily bright. Because Betelgeuse is hundreds of light years away, that explosion would not threaten Earth. It could, however, become an extraordinary sight in the sky and potentially remain visible for months, even during daytime. The exact timing is highly uncertain. Estimates have often placed its final explosion on astronomical timescales of roughly tens or hundreds of thousands of years, while newer research emphasizes that the star could have substantially longer to live. The famous dimming of Betelgeuse in 2019 and 2020 also caused excitement because some people wondered whether the star was approaching its final explosion. Observations instead showed that the dramatic fading was caused by a huge eruption from the star that produced dust and temporarily blocked much of its light. More recent observations have also strengthened evidence that Betelgeuse has a smaller companion star. That discovery helps astronomers understand the unusual behavior and evolution of this enormous star. The most interesting part is the combination of certainty and uncertainty: Betelgeuse is expected to explode eventually, but nobody can give us a reliable date for when the event will become visible from Earth.

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