Asteroid: A rocky object that orbits the sun and has an average size between a meteoroid and a planet.Comet: An object made mostly of ice and dust, often with a gas halo and tail, that sometimes orbits the sun.Ī meteoroid is “a small, rocky or metallic body revolving in interplanetary space around the sun.A meteoroid is significantly smaller than an asteroid, ranging from small grains or particles to the size of large boulders.” In other words, a meteoroid is a “space rock” smaller than an asteroid. In the context of these terms, the word meteor might sound like the most general, but that’s not actually the case. We’ve started with the word meteoroid because meteoroids can become meteors or meteorites. What is a meteor?Ī meteor is a “a meteoroid that has entered Earth’s atmosphere.” Basically, it’s a small body of rock or metal that used to travel around in space, but that got sucked into Earth’s gravity. The friction from the atmosphere makes it heat up and glow, sometimes making it visible as it streaks through the sky. What’s visible from Earth is a bright, fiery streak in the sky, and we also use the word meteor to refer to that streak (as opposed to the body itself). A particularly bright meteor can be called a bolide or a fireball, especially if it explodes.īecause meteors streak so brightly across the sky, the adjective meteoric is sometimes used metaphorically to describe something sudden, brilliant, and swift, especially in the phrase meteoric rise. Some people object to this phrase, because, by definition, meteors fall, not rise. The origin of the word meteor, though, might get a rise out of these nitpickers. The word meteor, which has been used in English since at least the 1570s, ultimately comes from the Greek meteōron, meaning “a thing in the air.” This is derived from the root verb aeirein, meaning “to raise.” The other words derived from meteor are based on this same root. Now that we know where the word meteor comes from, let’s find out where meteors come from. For example, if chunks of a comet melt off as it passes close to the Sun, this debris can be left behind to later dazzle us Earthlings with a meteor shower.Remember, meteors are meteoroids that enter Earth’s atmosphere. We sometimes see the glowing hot air created by these burning meteors and dub them “shooting stars.” Meteor showers occur when the Earth passes by many meteors at once. The resistance on the rock due to the Earth’s atmosphere causes its temperature to rise. What is a meteor and a meteorite?Ī meteor is simply an asteroid that attempts to land on Earth but is vaporized by the Earth’s atmosphere. Comets formed at farther distances from the Sun, beyond what we call the frost or snow line and past the orbits of Mars and Jupiter, where temperatures were low enough for water to freeze. However, asteroids formed toward the inner regions of our solar system where temperatures were hotter and thus only rock or metal could remain solid without melting. What is a comet?Ĭomets are also composed of material left over from the formation of our solar system and formed around the same time as asteroids. Smaller dust fragments that never made their way into planets are left behind as asteroids. When the cloud of gas and dust collapsed to form our Sun, much of the remaining material went into forming the rocky terrestrial and gas giant planets orbiting our star. The terms asteroid, meteor, meteorite, and even comet are often used interchangeably.but what is the difference? What is an asteroid?Īsteroids are rocky objects smaller than planets that are left over from the formation of our solar system. Despite their small physical size, however, these space rocks offer important clues as to how our solar system formed. Adding up all of the mass in every asteroid in our entire solar system totals only less than the mass of our Moon.
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