From the deserts of the Middle East, Arab skywatchers paid particular attention to a celestial giant. He strode into the evening sky during winter, and boasted some of the brightest stars in the heavens. His right hand was marked by a dazzling orange star named Bet al Jauza.
Today, we know the star by a slightly different version of the name: Betelgeuse. It's in Orion, the hunter, which tromps across the south on winter nights.
Betelgeuse is one of the most interesting stars in the galaxy. It's big and bright, and it pulses in and out like a beating heart. And soon -- at least in astronomical terms -- it'll blow itself to bits.
Betelgeuse is about 15 times heavier than the Sun. Its core is intensely hot, but its outer layers are cool, which is why the star appears orange. Its diameter is hundreds of times greater than the Sun's. If it took the Sun's place in our solar system, it would swallow Earth and several other planets.
But Betelgeuse rhythmically expands and contracts, so its diameter can vary by millions of miles. When it shrinks it gets hotter, so it gets brighter, too.
Betelgeuse is ticking down toward a huge explosion. Eventually, it'll stop producing energy in its core. The core will collapse, and the star's outer layers will blast outward. For a few weeks, Betelgeuse will shine brighter than an entire galaxy of stars -- shouting out its death to the universe.
We'll talk about one of Orion's more sedate stars tomorrow.
Script by Damond Benningfield, Copyright 2003, 2007
For more skywatching tips, astronomy news, and much more, read StarDate magazine.
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