Asteroids, Comets, and Meteors: A Guide to Space Rocks in the Night Sky
A piece of the Campo del Cielo meteorite. (image credit: Carlos Zito)
Post Author - Peter Bashaw
Across the solar system, there are trillions of pieces of rocky debris leftover from the formation of the sun and our planets. These space rocks have many different names that are mistakenly used interchangeably, so if you’ve ever wondered what’s a meteoroid and what’s a meteorite, or the difference between an asteroid and a comet, we'll clue you in!
Asteroids are rocky objects that make up the asteroid belt between the four inner terrestrial planets and the four outer gas giants. The difference between an asteroid and a meteoroid is a question of size, with anything smaller than one meter in diameter being a meteoroid. Asteroids on the other hand can be very large, with the largest being the dwarf planet Ceres with a diameter of 940 kilometers.
When a meteoroid falls to Earth, friction from the atmosphere produces light and heat. This is what we call a meteor. Seen at night, we might call this a shooting star, or if it’s particularly intense a fireball. Air resistance usually breaks up meteoroids as they fall, scattering their pieces across a strewn field. The material that makes it to the Earth’s surface is called a meteorite.
Comets are an entirely different kettle of fish. These space rocks have a core of material from the solar system’s formation and are surrounded by a layer of dust and ice. Unlike asteroids, they follow their own orbits around the sun. If gravitational forces draw them to the sun, the ice begins to vaporize and leak through the comet’s crust in jets. This produces a cloud of dust and ice around the comet called a coma, as well as a tail of material that can stretch across millions of kilometers.
Looking for some hands-on experience with space rocks? Lucky for you we have plenty in our Meteorite Collection...
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