Wednesday, April 29, 2009

April Showers (or the Lyrids)

Whenever a comet makes its nearest approach to the sun, some pieces break off from its nucleus. The larger fragments take up orbits near the parent comet, but some fall behind, so that the comet’s path is eventually filled with these tiny micrometeoroids. Periodically, the earth’s orbit intersects with a cluster of such micrometeoroids, resulting in a meteor shower as the fragments burn up in our upper atmosphere.
Meteor showers associated with certain comets occur with high regularity. They are known by the constellation from which their streaks appear to radiate. The following table lists the most common and prominent showers. The shower names are genitive forms of the constellation name; for example, the Perseid shower comes from the direction of the constellation Perseus, the Lyrids from Lyra. The dates listed are those of maximum expected activity, and you can judge the intensity of the shower by the estimated hourly count. The table also lists the parent comet, when known.
You can detect meteor showers on your FM radio or even on unused VHF television frequencies. But if it’s clear outside, we suggest that you take your radio outside, and as you listen for distant radio stations to pop up, look up at the skies and watch as well. It might be hard to believe that most of those streaks of light are following meteoroids no larger than a pea. But be thankful that they are!

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