Double, Double

Low in the northeast at sunset is the "demon star," Algol, representing the head of the Medusa. For most of the time it is as bright as the stars of the Big Dipper, but every three days it dims for about ten hours. Of course, in ancient times no one knew the cause of this dimming. It was simply called "the demon star," a herald of bad luck.

Then, in about 1780, astronomers deduced that Algol had a faint companion circling it; every three days this companion would be exactly between Algol and the Earth, partially eclipsing it. Because of the glare of Algol itself, this companion has never been seen through a telescope. It can only be seen with your mind.

To find Algol, first find the "W" of Cassiopeia, amost overhead. The right half of the "W" points to he Andromeda galaxy, the left to Algol (just before you ger to the Pleiades.)

Algol is certainly not the only star in the sky to have a companion circling it. Almost two-thirds of the stars in the sky are actually two or more stars of which we see only the brighter component.

Our Sun is in the minority being a "lonely-only." The star we call Capella, in the north-east, is really a system of six stars. Even Polaris, the North star, is double.

The more we understand about the stars, the better we can see them. And sometimes it's only with our minds that we see them at all.

(10/30/02)