Walking in From Arcturus

Arc to Arcturus

By Bob Berman|Thursday, April 01, 1993
RELATED TAGS: STARS
Spring’s brightest star reminds me of a recent furor in nearby Woodstock, New York. In a town where nothing is surprising, a famous psychic was drawing crowds by claiming that he was inhabited by a being from Arcturus. No big deal, he said; many people’s brains are occupied by Arcturians. Such uninvited neural advisers were called walk-ins, and they lectured widely. Needless to say, the audience paid an entrance fee--in terrestrial cash.

Such astroscams are easy to debunk. The psychic, like most people, was apparently unaware that only some five dozen stars have popular names in common use. Most other nearby stars have designations like HD 225213. If aliens were to arrive, it’s implausible that they’d just happen to come from one of the few stars with a catchy name like Arcturus.

But if I were a walk-in, I’d be proud to hail from there. And not just because Arcturus is the brightest star ever seen high overhead from our part of the world, and the fourth brightest in the sky. More notable is that Arcturus is the only celestial object to have opened a world’s fair. More notable still is that it’s the only major star that will soon disappear.

Even beginners can spot it easily: the Big Dipper’s handle curves in its direction. Arc to Arcturus has been the counsel to young stargazers almost as often as Don’t put your fingers on the lens. These nights, while Orion’s army of jewels crumbles into the west, and while the south is ablaze with dazzling Jupiter, the eastern sky offers solitary Arcturus. Its pumpkin-colored rays emanate from a sphere so large that 15 billion Earths could fit inside.

Can you feel any of its heat? Only if you’re unusually sensitive. The warmth we get from Arcturus is equal to that of a single candle five miles away.

That energy was put to good use back in the spring of 1933, for the opening of the Chicago World’s Fair. Arcturus’s light was focused through a telescope onto a photocell that tripped floodlights signaling the official start of the festivities. Arcturus was chosen because it was believed at the time to be 40 light-years away; thus, fair planners reasoned poetically, the same light that had left the star 40 years earlier, when a previous Chicago fair was closing, would open the new one. A wonderful idea, even if Arcturus is now known to be only 36 light-years away.

But Arcturus will not stay put. Restlessly, it follows a peculiar path around our galaxy’s center, one that avoids the galactic plane in which our own sun and most other stars orbit. Alone among the night’s bright stars, it springs upward out of the Milky Way’s spiral flatness, only to dive through it about 100 million years later, going the other way. Instead of traveling with us like adjacent horses on a carousel, Arcturus is plunging down at us from above.

This causes changes in its brightness and location. Just 500,000 years ago--a hiccup in time--Arcturus was invisible. It’s been steadily approaching us ever since (since you started reading this, it’s come 300 miles nearer). Skimming through our neighborhood, it’s now at almost its closest and brightest point. Half a million years from now, before we ourselves have gone even two-hundredths of the way around the galaxy’s center, it will have faded into oblivion forever.

When we next return to this part of our galactic orbit, Arcturus and its enterprising walk-ins will be somewhere else. So greet it warmly during this one cycle in time when our paths cross, for we will never meet again.
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