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What are the differences between asteroids, comets, meteors, and meteorites? Get to know your space rocks! Plus, discover how you can find a meteorite that’s fallen to Earth!
To put it simply, asteroids, meteoroids, meteors, and meteorites are just different types of “space rocks” floating in space. All of these objects orbit our Sun similar to Earth and other planets.
The largest rocks in space are called asteroids. Think of asteroids like minor planets which orbit around the Sun. They’re left over from the early formation of our solar system about 4.6 billion years ago. Most asteroids are found in a ring between the orbit of Mars and Jupiter called the asteroid belt because the gravity of newly formed Jupiter caused small bodies to collide with one another and fragment. Some asteroids are round, some are elongated, and some even have a satellite. Some are the size of a pick-up truck. Others are hundreds of miles across. Through a telescope, as asteroid appears as a point of light.
Comets are also large objects which orbit the Sun. However, instead of being rocky, they are icy and know for their long streaming tails. Like asteroids, comets are also ancient objects from the formation of our solar system. They have a frozen core or nucleus and made of dust and ice. Most comets exist far out in the solar system; some are beyond the orbit of Neptune called the Kuiper Belt. They can be pulled towards us by gravity. When a comet gets close to the Sun, its ice and dust content start to vaporize; the sunlight and particles shining through the dust and gas create those bright tails that stretch behind the comet for millions of miles.
Over time, asteroids break down into smaller particles of rock called meteoroids. Meteoroids orbit our Sun, too. Meteoroids are usually the size of a pebble but can be larger or smaller. When one of those meteoroids enters the Earth’s atmosphere and vaporizes, it is called a meteor—or, “shooting star.” The meteor heats up and makes the air around it glow. We see a streak of light. Scientists think that up to 10,000 tons of meteors fall on the Earth each day, but most are no bigger than a speck of dust.
When a meteoroid survives a trip through the atmosphere and hits the ground, it’s called a meteorite. They resemble Earth rocks, so they can be difficult to identify, but they usually have a burned exterior that can appear shiny. They’re easiest to find in sandy deserts of frozen northern regions because they appear dark against a light surface. They’re typically small in size, between the size of a pebble and a fist.
Some planets and moons don’t have enough atmosphere to protect them against meteor and asteroid impacts. Earth’s Moon, Mercury and even Mars are covered with round impact craters from these collisions.
As mentioned above, we see meteor showers, or shooting stars, when the Earth travels though clouds of particles left by asteroids (or, comets).
A meteor shower appears to originate from a single point in the sky, the “radiant”. Meteors seen near the radiant are approaching the observer and will appear as short streaks in the sky. However, meteors seen 45 to 135 degrees from the radiant are moving in a more parallel direction to the observer. These meteors will produce longer streaks in the sky.
Meteor showers are usually named for the constellation in which their radiant lies at the time of shower maximum. Thus, the Leonid meteor shower (peaking about November 18) will appear to radiate from the constellation Leo.
The best and most reliable showers are usually the Perseids, between August 11 and 13. See our Perseids Guide!
You’ll see the most meteors on a clear, dark night during a new Moon. If you live near a brightly lit city, drive away from the lights and toward the constellation from which the meteors will appear to radiate.
To see the most meteors, watch as late in the nighttime as you can, up till dawn. To view a shower, the meteor shower radiant must be above the horizon—most radiants are up by around midnight.
Grab and lawn chair and look up: Most meteor showers are very fast! They flash by in a second or less.
Finding a Meteorite!
Every day, dozens of small meteorites fall to the Earth. Those that are seen coming down are called “falls.” Those that are recovered on the ground are called “finds.”
Meteorites are of great interest to researchers as studying them helps us to understand the formation and evolution of the solar system.
Meteorites can be recognized by their dark, often scalloped exterior. Usually they will be denser than a ‘normal’ rock and will often be attracted to a magnet. If recovered, it is best to place them in a clean plastic bag or wrap them in aluminum foil. Meteorites should also be handled as little as possible to help preserve their scientific value.
If individuals plan to search, they should always obtain permission of the landowner before venturing onto private land!
Here’s how to find meteorites:
Tape a strong magnet to the end of a broom handle. A meteorite contains a lot of iron, so it will stick to your magnet.
If it’s an ordinary rock with lots of iron, it may stick too. You can tell a meteorite by its fusion crust, a thin, glassy coating that formed when the meteorite superheated during its fall through Earth’s atmosphere.
Fun Meteorite Facts
The largest meteorite ever found in the United States weighed 15 tons and was found in 1902 in Willamette, Oregon.
Since 1978, teams of scientists have collected over 15,000 meteorite specimens from Antarctica. They are easier to find on that continent’s snow-white surface.
One of Canada’s most notable meteorites was found near Tagish Lake in northern British Columbia by Jim Brook on January 25, 2000. He almost mistook it for wolf poop.
Don’t worry. Most meteors are very small and the Earth is huge. Despite the current hype, and many rumors, there has been only one confirmed case of a meteor actually hitting anyone.