You are here

Orion Rising

November 22, 2013

The longer, colder nights of late autumn bring one of the great skywatching treats of the year: the return of Orion to prime time viewing hours. The hunter is in good view in the east by about 9 o’clock, and climbs high across the south later on.

The constellation’s most prominent feature is the hunter’s belt — a short line of three fairly bright stars. As Orion rises, the belt extends almost straight up from the horizon.

Two of the brightest and most impressive stars in all the night sky flank the belt. Orange Betelgeuse is to the left of the belt, with blue-white Rigel to the right.

Both stars are supergiants — they’re much bigger, heavier, and brighter than the Sun, with Betelgeuse the bigger of the two. If it were to take the Sun’s place in our own solar system, it would engulf half of the planets — Mercury, Venus, Earth, and Mars — and perhaps even the next one out, Jupiter; more about that tomorrow.

Such massive stars burn through the nuclear fuel in their cores in a hurry. Betelgeuse is only about 10 million years old, compared to four-and-a-half billion years for the Sun, yet it’s already near the end of its lifetime. Within the next couple of million years, it’ll explode as a supernova, briefly shining as brightly in our sky as the full Moon.

Rigel is about the same age as Betelgeuse, so it should soon puff up and get redder, just as Betelgeuse has. It, too, will then explode as a supernova — briefly adding to the luster of beautiful Orion.


Script by Damond Benningfield, Copyright 2013

Get Premium Audio

Listen to today's episode of StarDate on the web the same day it airs in high-quality streaming audio without any extra ads or announcements. Choose a $8 one-month pass, or listen every day for a year for just $30.