Meteors and asteroids: What is the difference?
Feb. 15, 2013 | 4:59 p.m.
An image of the meteor that streaked across the sky of Russia’s Ural Mountains on Friday morning . (Nasha gazeta, http://www.ng.kz)
A meteor brighter than the sun streaked across a portion of Russia on Friday. At the same time, an asteroid the size of half a football field was zipping by Earth, closer than the moon.
But what is the difference between a meteor and an asteroid?
An asteroid is a rocky body that orbits the sun. Some asteroids are the size of small boulders, others can be up to several miles in diameter.
Larger asteroids are sometimes called planetoids or minor planets. Very small ones are called meteorids. A meteorid can be smaller than a marble.
When an asteroid or a meteorid enters the Earth’s atmosphere it burns up and creates a streak of light (a shooting star). That streak of light is called a meteor.
Most meteors burn up entirely as they pass through the atmosphere, but sometimes they don’t. A piece of a meteor that actually hits the Earth’s surface is called a meteorite.
The meteor that caused the streak of light across Russia was an asteroid before it hit the Earth’s atmosphere. NASA scientists estimate it was about 45 feet across, or about the size of a locomotive, before it was smashed to pieces by the force of hitting Earth’s atmosphere.
Asteroid 2012 DA14, which brushed past Earth on Friday, was 140-feet in diameter. Since it did not enter Earth’s atmosphere, and has continued on its way, it is still an asteroid.
– Deborah Netburn
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