If you go out and look at the stars every night like I do, you might have noticed something different up there in the sky. The stars slowly scroll across the heavens each night because of the rotation of the earth, and they also move with the changing of the seasons.
Rarely does anything happen that we can actually notice because our lifetimes are so insignificant compared to the lives of the stars. One of the brightest stars in the sky is getting dimmer. What would make a star change in brightness? They live millions or even billions of years and generally shine with a steady intensity for most of their lifetimes, so it is very unusual to see one get brighter or dimmer.
The star I am talking about is Betelgeuse, a strange name for a strange star. Check out the constellation Orion, which mid-winter is riding high in the south in the early evening. In the upper left-hand corner, the star Betelgeuse shines with an orange-reddish light. Its name is the derivative of an Arabic word meaning shoulder of the giant or even armpit of the giant. Some linguistic scholars say that the name predates the Arabs, and actually is a Babylonian name meaning armpit of the sheep wearing the white girdle. You see back then nobody had TVs or I-Pads to distract them, and their imaginations were free to run wild.
Betelgeuse is a very unusual star right at the end of its life cycle. Astronomers have known for years that we are watching a dying star about ready to go in a very spectacular fashion. Like an old man wheezing and gasping for his last breath, Betelgeuse gets brighter and dimmer over a period of months or years. It is a well-known fact that sooner or later, probably later, the star will explode in a titanic supernova explosion, one of the most violent events in the universe. An occurrence like this does not happen every day. The last time humans witnessed such an event with their naked eyes was in the year 1604.
Astronomers have said that such a happening is tens of thousands of years in the future for Betelgeuse, but no one has seen such a rapid dimming of the giant red star before. It is 640 light-years away, more or less, which means that this dimming happened 640 years ago. It has taken that long for its light to get here for us to see. Does it mean that it will blow its top in the near future, like tomorrow night? Probably not, but if it did, we would be treated to an awesome display of fireworks.
The last supernova back in the year 1604 was a quarter of the way across the galaxy at 20,000 light-years distant from us. Even that far away it attained a brightness 16 times that of Venus, which is the brightest thing up there besides the moon and the sun. Betelgeuse is much closer, so stand by for something truly spectacular. Imagine a star in the sky brighter than the full moon and visible even during the daytime.
Do we have anything to worry about? The explosion will probably not blow us off our little world, but some scientists predict that we might receive enough radiation from the blast to alter genetic evolution here on earth.
While you are out there looking at Betelgeuse, be sure to check out all the other bright stars nearby. Rigel is the blue-white one down and to the right diagonally across the constellation of Orion from that red giant. Sirius, below and to the left of Orion, is the brightest star in the night sky. Over in the southwest just after sunset, that really dazzling one is not a star at all, but the beautiful planet of love and beauty, Venus.
I am going to watch Betelgeuse very carefully every clear night, but I’m not holding my breath, we probably will have to wait thousands of years before anything truly amazing happens.