A shooting star is not a star at all. It's a meteor.
Go out on a clear night away from city lights and look up into the night sky for a while. You are likely to see some bright streaks of light that appear to fall from the sky. We call those streaks shooting stars or falling stars. But with all the stars that seem to fall from the sky, you may wonder why the number of stars we see doesn't seem to change. That's because a shooting star is not a star at all.
If Not Stars, Then What?
The bright streaks we call shooting stars are tiny bits of dust and rock smaller than a marble, known as meteoroids. They fall into Earth's atmosphere at incredibly fast speeds and leave a trail of light as they burn up from atmospheric friction. According to the National Aeronautics and Space Administration's StarChild website, the trail of light is called a meteor. If any of the falling meteoroid actually hits the Earth, it's called a meteorite.
Meteor Showers
About a dozen times a year, says NASA, people are likely to see unusually large numbers of meteors in what are termed meteor showers. These events occur when the Earth crosses the orbit of a comet, and debris shed from the comet showers our planet. The showers recur every year and are named for the constellations where the meteors appear to originate. The most active meteor showers are the Perseid in mid-August and the Geminid in mid-December. The typical meteor shower lasts three to five days.
Meteorite Craters
A few thousand meteoroids each year are large enough to reach the ground as meteorites, but have been slowed enough by the atmosphere that they leave no big marks when they hit. But there also are the rare large objects that hit the ground at several times the speed of a rifle bullet and leave craters. The curators of the famous Barringer Meteor Crater in northern Arizona near Winslow say it's a mile wide and 570 feet deep. It was created 50,000 years ago by the 2.5 megaton impact of a meteorite 150 feet across, traveling over 7.5 miles per second. The object was vaporized.
Dinosaur Killer
At least one giant meteoroid may have struck the Earth with devastating global consequences. There is the 100-mile wide Chicxulub impact crater beneath present-day Mexico's Yucatan Peninsula, created by an object several miles in diameter that was credited by geologist Walter Alvarez with exterminating the dinosaurs and many other species 65 million years ago.
Meteorite Science
The scientific study of meteorites is called meteoritics. The New England Meteoritical Service says meteorites are genuine extraterrestrial visitors. Apart from the moon rocks our astronauts brought back, meteorites are the only material objects on Earth that did not originate on this planet. Scientists who study meteorites hope to learn more about the formation of the solar system and conditions in outer space.
Tags: bright streaks, fall from, meteor showers, shooting star, shooting star star, star star, study meteorites
