Orionid Meteors

Two celestial lightshows will compete with each other this week — the full Moon and the Orionid meteor shower. And there’s no mystery about which one will win: It’s the Moon all the way.

The Orionids are streaks of light caused by debris from Comet Halley. When the comet passes near the Sun, some of the ice at its surface vaporizes. That releases particles of rock and dirt into space. They spread out along the comet’s path. Earth plows through this path every October. As it does so, some of the comet dust slams into the atmosphere at almost 150,000 miles per hour.

A grain’s plunge into the atmosphere creates friction. That heats and erodes it. It also creates a trail of plasma — a super-heated gas that glows. And that’s what we see when a meteor streaks across the sky.

The Orionids are expected to reach their peak in the wee hours of Thursday morning. Under dark skies, away from the pesky glow of city lights, the shower usually produces up to a dozen or so meteors per hour.

Unfortunately, though, the Moon will be full on Wednesday morning. It’s the Hunter’s Moon — the full Moon after the Harvest Moon.

When the meteor shower hits its peak on Thursday, the Moon will still be almost full. It’ll be nice and bright, and in view all night long. Its brilliant glare will overpower all but the brightest meteors — making the Moon the hands-down winner in the pre-dawn sky.

Tomorrow: Studying magnets among the stars.

Script by Damond Benningfield