‘Betelgeuse could become a supernova any day now’

Betelgeuse – the somber red star in the shoulder of the constellation Orion the Hunter – is one of the largest stars visible to the eye alone.

The star Betelgeuse might someday appear as a spectacular explosion in our sky, a supernova.

Brad Schaefer is an astronomer in Baton Rogue, Louisiana. He said Betelgeuse could become a supernova any day now.

Brad Schaefer: For all we know, Betelgeuse has just gone supernova. Betelgeuse is about a thousand light years away. So if Betelgeuse has gone supernova anytime in the last thousand years, the light of this supernova explosion could be speeding to us even as we speak – maybe it will arrive tonight – and suddenly Betelgeuse will flash into being brighter than a million full moons in the sky – all up above us. It would be a spectacular sight.

Schaefer said that if Betelgeuse replaced the sun in our solar system, Earth would be submerged inside this star. Its outer layers would extend halfway to Jupiter. Betelgeuse is a red supergiant. It long ago burned up its main star fuel – hydrogen – that keep stars like our sun shining.

Stars like our sun shine due to thermonuclear fusion. They fuse light atoms in their cores to make heavier atoms. Eventually stars run out of the raw materials needed for fusion. Then, if a star is massive enough, it’ll explode as a supernova.

Schaefer said that even if Betelgeuse became a supernova, it would be too far away to do us any actual harm.

By the way, if our sun went supernova, just the blast wave would destroy Earth. The nearest star to our sun, Alpha Centauri, is not likely to become a supernova. But if a star at that distance did go supernova, there would be very heavy damage here on Earth.

How close could Earth be to a supernova, without suffering damage? Schaefer said that people argue back and forth about this (there are many unknown effects that go into these sorts of calculations), but, he said, a typical figure might be 100 light years away.

Thanks today to Research Corporation – a foundation for the advancement of science.

NOTE: Schaefer was off a bit on the distance to Betelgeuse. Its estimated distance is 520 light-years away.

Our thanks to:
Brad Schaefer
Louisiana State University

March 8, 2008

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