Perseid Meteor Shower Lights Up the Sky
LOS ANGELES (CNN) — A celestial fireworks show peaks Monday and Tuesday as Earth passes though the dust of a comet’s tail.
Humans around the world have witnessed the Perseid meteor shower every August for at least 2,000 years, with dozens of meteors streaking across the sky each hour.
Your view is best after midnight until just before sunrise. Get away from city lights, if possible, for the full effect. A waning crescent moon means less light in the sky to compete with the meteor display. Next year’s show will be dimmed by a full moon.
The annual sky spectacular happens when our planet’s orbit around the sun passes near Comet Swift-Tuttle’s path, which goes by every 130 years. The last close encounter with the comet was 20 years ago, but it left grains of dust in its wake.
The bright streaks you see are “interplanetary dust” burning up as it collides with our atmosphere at about 133,000 mph, according to NASA micrometeoroid expert Diego Janches. “The fragments are either remnants from the solar system’s formation, or they are produced by collisions between asteroids or comets from long ago.”
“Each such fragment is approximately the size of a dime, but the more constant, sporadic meteoroids have been around much longer, breaking down over time into tiny fragments only about as wide as a piece of human hair,” according to NASA.gov.
While the meteor show is entertainment for most, it is a research opportunity for Janches and other NASA scientists. They’ll use radar systems around the globe to watch the fragments of sodium, silicon, calcium and magnesium enter the atmosphere.
“The small meteoroids feed the atmosphere with all these extra materials,” Janches said in a NASA.com posting. “They come in, release metallic atoms that get deposited in the mesosphere and then get pushed around from pole to pole by the general global circulation. So by using the metals as tracers, you can answer some important questions about the general composition and movement of the atmosphere.”
By Alan Duke