Leonid Meteors

StarDate: November 15, 2009

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In a lot of old movies, you just couldn't go anywhere in the solar system without facing the peril of a meteor shower -- big, flaming hunks of debris that threatened to blast a spacecraft to smithereens.

The reality is a lot less dramatic. There are swarms of particles in space, but most of the particles are so tiny that they present little danger. Even so, they can be a nuisance, and spacecraft operators take precautions during meteor showers.

An example is the Leonid shower, which is at its best this week.

The shower occurs when Earth crosses the orbital path of Comet Tempel-Tuttle, which is strewn with bits of rock and dust from the comet. When the particles hit Earth's atmosphere, they vaporize, forming bright streaks of light.

Outside the atmosphere, though, the particles are moving at tens of thousands of miles an hour, so even though most are no bigger than BBs or small pebbles, they pack quite a wallop.

In 2001, a Leonid hit the orbiting XMM Newton X-ray telescope, slightly damaging its instruments. Two years later, another Leonid hit the Chandra X-Ray Observatory. Chandra wasn't damaged, but the impact did make it wobble for a few seconds.

To protect their valuable spacecraft, operators sometimes point them away from the meteor stream, close their hatches, and shut down some systems for a while. That makes sure that the craft are safe from the perils of a meteor shower.

More about the Leonids tomorrow.

Script by Damond Benningfield, Copyright 2006, 2009

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