Sitting on the shoulder of the constellation of Orion with a distinctly reddish hue, Betelgeuse is one of the more recognizable stars in the night sky. But it is also one of the fastest changing. While Ptolemy described it orange-tawny, Chinese observers three centuries earlier say it was yellow.
More recently, astronomers classified Betelgeuse as a red giant, a star that is near the end of its life. That meant Betelgeuse is due to explode as a supernova sometime in the next few hundred thousand or a million years. They also discovered it was pulsating — becoming brighter and dimmer over periods ranging from a few months to a few years.
