When bursts of light seem to streak from the sky towards the ground, you may be witnessing a meteor shower. These streaks of light are usually harmless. On rare occasions, a meteor shower will produce a rock or meteorite large enough to survive its descent into our atmosphere and to strike the Earth. So how does this happen? Where do meteor showers come from? Just look to the comets for the answer!
Comets are collections of dust, ice, and other materials that orbit our sun. As they get close to the sun, the various components of the comet will start to ignite, creating the blazing trail effect that we can sometimes see with the naked eye. When a comet moves through its orbit, some of its component materials will separate from its body and float alone in space. These materials form a trail of discarded matter. The trail is primarily composed of extremely small particles of ice and dirt (think of objects that are the size of grains of sand or even smaller), with a smattering of larger particles of various sizes. If the Earth’s orbit takes it into the path of the comet trail, the particles will be attracted by Earth’s gravity and fall towards the ground. Most of these particles are very tiny and they will vaporize almost instantly during their descent through the atmosphere. Bigger particles will travel further through the atmosphere until they disintegrate. The bright lines we see in the sky are the meteors burning up in our atmosphere.
Sometimes the streaks of light are from larger pieces of comet debris. Pieces of rock that are large enough to survive their fall to the ground are called meteorites. This name distinguishes them from the meteors that disintegrate during their entry into our atmosphere. Meteorites can come in a wide range of sizes. Scientists think that some of the largest meteorites to hit the earth were very large and may have had catastrophic effects on parts of our planet.
The best known meteor showers are annual events. These meteor showers have names like “Leonid” or “Perseid”. The names are derived from the names of the constellations which the meteor shower seems to emanate from. For example, the Leonid shower seems to come from the Leo constellation, while the Perseid shower seems to come from the Perseus constellation.
A more complete listing of the different types of meteor showers includes:
– Quadrantids
– Lyrids
– Aquarids
– Perseids
– Orionids
– Leonids
– Geminids
“Falling stars” or “shooting stars”, as meteors are sometimes called, are not truly stars. Nonetheless, they do make a beautiful light in the skies as they fall to the ground, briefly rivaling their namesakes for a moment. There are a number of opportunities each year to witness a meteor shower, so if you want a free and interesting way to spend a summer’s evening, get ready to camp out under the start and watch a meteor shower. Just don’t sit too close to where the meteor shower is happening, just in case
SOURCE
http://stardate.org/nightsky/meteors/
