Anchorage Daily News

Want to wish upon a falling star? You might be able to do so this morning as Earth makes its regularly scheduled pass through the heart of the Orionid meteor belt, the celestial residue of Halley's comet.

Observers here could spot as many as 20 meteors an hour plummeting toward Earth.

Or not.

If the skies are cloudy, or the moon is too near, or the peaks of the Chugach block your view, then the heavenly show might occur out of view, says UAA astronomy professor Travis Rector. If so, try again on Wednesday. This year the two-week-long shower peaks Oct. 20-22.

"It's sort of like watching the northern lights," Rector said. "You have to have a little bit of patience."

Skywatchers say the Orionid meteor shower is one of the two or three most spectacular meteor events each year. It's so named because its bursts of light appear to emanate from an area just above the left shoulder of Orion the Hunter, a constellation most easily located by first spotting the slanted line of three stars in Orion's belt.

At this time of year in Anchorage, Orion rises in the east around midnight, so the Chugach Mountains might block it from your view. But it becomes more visible as it swings to the south toward morning -- 5 a.m. might be ideal.

So what's happening up there?

Astronomers say it's a light show left behind by Halley's comet, which orbits the sun once every 76 years. The last time the comet passed by Earth was 1986.

"Comets are basically giant dirty snowballs in space, like that big chunk of ice that forms on your rear bumper," Rector said.

When they pass near the sun, a portion of the comet evaporates, leaving behind a trail of wet grit, which eventually enters the Earth's atmosphere in the form of meteors.

Children mistakenly call the meteors shooting stars, but they're actually no larger than grains of sand, Rector said.

Each October, when the Earth's orbit intersects Halley's orbit, some of those grains rocket toward us and briefly catch on fire.

"It's just friction as it runs into Earth's atmosphere at several thousand miles an hour," he said.

A potential problem viewing the meteors this morning might be the light of a half-moon in the vicinity of Orion, Rector said. The moon will be farther from Orion on Wednesday, so try, try again.

Find George Bryson online at adn.com/contact/gbryson or call 257-4318.

Orionid meteor shower

WHEN to watch: Early morning today and Wednesday is best, especially if the skies are clear.

WHERE TO LOOK: Bursts of light appear to emanate from an area just above the left shoulder of Orion the Hunter, a constellation most easily located by first spotting the slanted line of three stars in Orion's belt.

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