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Moon and Betelgeuse

August 9, 2015

The stars all look like they’re “fixed” on the dome of the night sky — they don’t change position from night to night, or even century to century. But that’s only because they’re so far away. In reality, the stars all streak around the galaxy like race cars on a dry track.

Consider Betelgeuse, a bright orange star that stands to the lower right of the Moon at dawn tomorrow.

The star marks the shoulder of Orion, the hunter. It’s held that spot since long before people began drawing the constellations. And it’ll stay there for tens of thousands of years longer.

Yet Betelgeuse is moving in a hurry. Just how big of a hurry depends on how far it is. A space telescope designed to measure stellar distances found that Betelgeuse is about 640 light-years away. But other measurements say there’s a lot of uncertainty in that number.

If the distance is 640 light-years, then Betelgeuse is moving away from us at more than 50,000 miles per hour.

Despite that quick pace, Betelgeuse won’t disappear from view anytime soon. It’s one of the biggest, brightest stars in our region of the galaxy. Sometime in the next million years or so, it’ll explode as a supernova. It’ll still be so close to Earth that it’ll shine as brightly as the full Moon for several weeks. After that, it’ll spend many months fading away — and eventually disappear in the depths of the Milky Way.


Script by Damond Benningfield, Copyright 2015

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