The ghoul and the stargazer

Long ago the star Algol in Perseus was regarded as deeply ill-omened. Its name means “the ghoul,” after the Arabic, al-Ra’s al-Ghul, the Head of the Ghoul.

Why the ancient astronomers thought it was evil is anybody’s guess. Ancient Hebrews called it Rosh ha Satan, Satan’s Head. Worlds away, Chinese astronomers called it Piled-up Corpses. The Romans used versions of Caput Gorgonis, the Gorgon’s Head, which gets to the heart of the matter, so to speak: To the Greeks it was the eye of Medusa’s head dangling bloody from Perseus’ hand.

Perseus, up there, is eternally rescuing Andromeda, just west of him. On his way back from killing Medusa by cutting off her snake-ridden head, he spotted Andromeda being tormented by sea creatures and snatched her away by showing the monsters the Gorgon’s face and turning them to stone.

We call this a “myth,” a word scientists of the past century have made synonymous with “falsehood.”

In this spirit, some astronomers playfully turn the ancient astronomers’ sense of Algol’s evil on its head, saying Algol is actually a “friendly” star because it provides unique information. And information is good.

The prince of darkness is a gentleman, it’s been observed.

This response from me, who’s a doctor but not a scientist, could result in my own demonization, or at least mean laughter. I’m of two minds about this.

One mind profoundly respects the scientific facts. Algol, apart from the horrors its names allude to, is one of the fascinating stars. It was the first “variable” star identified as an “eclipsing binary,” meaning it varies between brighter and dimmer because it is actually two stars orbiting each other and the darker periodically eclipses the brighter. A third star circling the other two sometimes jostles the eclipse.

What’s weird, from a scientific viewpoint, is how often the eclipse happens: every 2.8 days. The two stars whip around each other less than 6 million miles apart (it’s about 93 million miles from the Earth to the sun). The larger Class K giant star is, paradoxically, the dimmer of the two. When it cuts between us and the smaller but brighter Class B star, to our eyes the system dims. Weirder still, material is flowing off the surface of the K star into the much younger B star.

These are fascinating astrofacts. But in some inevitable way, the data about this extremity in the sky sink into my other mind and get a life of their own. The B star is cannibalizing its elder.

Algol is best seen from Maine in fall. One October night of broken clouds long ago, I spread the three legs of my small telescope and pointed it toward Perseus. Through the black barrel Algol quaked and glinted. It’s white, but has a peculiar shadowiness. I watched it shift in the lens from fiery to a sort of lurid dimness. Meanwhile cars rushed in the distance. An owl hooed. The hair prickled on my neck.

This cold night will turn us all to fools and madmen, I thought. Then something rustled, and a low-pitched, hollow whistling boiled out of the trees, more horrible than anything I’ve heard before or since.

I froze. Suddenly I was so terrified my hands shook, and for a moment my mind was split. A calm part of me was watching another, petrified part that would have run for the road if it could have gotten my legs.

I stopped looking through the telescope. The whistle subsided. What animal is that loud and terrible? What’s dead in the thicket?

Reassembling my wits, I turned the telescope away from Algol and just continued on, getting a breath of fresh light from galaxy M31. Then I packed up and left.

All this must seem pretty foolish. A star is not a Gorgon. But fishing in the dark for sanity, as I’ve done hundreds of times, my thoughts by some combination of fact and fiction ended up in fear and trembling.

Apparently the ancient astronomers had some such experience too. Here in the scientific age, somebody’s got to make the sacrifice and say, Yeah, it still happens. In central Maine, it might as well be me.

-DWILDE@BANGORDAILYNEWS.NET