What Is an Asteroid? — For Kids
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Asteroids — Elementary
The short answer
An asteroid is a small rocky object.
It orbits the Sun.
To orbit means to go around and around.
An asteroid is smaller than a planet.
It is larger than a pebble-size meteoroid.
Where do asteroids live?
Most asteroids live in one main place.
It is called the main asteroid belt.
The belt is between Mars and Jupiter.
Some asteroids follow paths that come near Earth.
What is a meteoroid?
Sometimes one asteroid smashes into another one.
Small pieces can break off.
Those pieces are called meteoroids.
Meteoroids can also come from comets.
What is a meteor?
A meteoroid can come close to Earth.
It can enter the air around Earth.
Then it vaporizes.
That means it turns into a streak of light in the sky.
That streak of light is a meteor.
People sometimes call it a “shooting star.”
But a meteor is not a star.
What is a comet?
A comet is not the same as an asteroid.
An asteroid is made of rock.
A comet is made of ice and dust. It is not rock.
A comet orbits the Sun too.
When a comet gets near the Sun, its ice and dust begin to vaporize.
That becomes the comet’s tail.
What is a meteorite?
Sometimes a piece does not vaporize all the way.
It lands on the ground.
Then it is called a meteorite.
NASA’s Johnson Space Center keeps a collection of meteorites.
The collection works like a meteorite library for scientists.
Very, very old
Asteroids formed long, long ago.
They formed when our solar system was new.
That was nearly 4.6 billion years ago.
So meteorites can tell scientists what the solar system was like back then.
Words to know
- Asteroid
- A small rocky object that orbits the Sun. It is smaller than a planet and larger than a pebble-size meteoroid.
- Meteoroid
- A small piece that breaks off an asteroid. Meteoroids can also come from comets.
- Meteor
- A streak of light in the sky. It happens when a meteoroid enters Earth’s atmosphere and vaporizes. People sometimes call it a “shooting star,” but it is not a star.
- Meteorite
- A piece that survives its trip through Earth’s atmosphere and lands on Earth’s surface.
- Comet
- An object that orbits the Sun, like an asteroid, but is made of ice and dust, not rock. It grows a tail when its ice and dust vaporize near the Sun.
- Orbit
- The path an object follows around the Sun. Asteroids and comets orbit the Sun.
Asteroids — Middle
The short answer
An asteroid is a small rocky object that orbits the Sun.
Asteroids are smaller than a planet, but they are larger than the pebble-size objects we call meteoroids.
A meteor is what happens when a meteoroid — a small piece of an asteroid or comet — enters Earth’s atmosphere and vaporizes, creating a streak of light in the sky.
Where asteroids are found
Most asteroids in our solar system are found in the main asteroid belt, a region between Mars and Jupiter.
But asteroids can also be in other locations around the solar system.
For example, some asteroids orbit the Sun in a path that takes them near Earth.
Meteoroids: small pieces that break off
Sometimes one asteroid can smash into another.
This can cause small pieces of the asteroid to break off.
Those pieces are called meteoroids.
Meteoroids can also come from comets.
Meteors: a streak of light
If a meteoroid comes close enough to Earth and enters Earth’s atmosphere, it vaporizes and turns into a meteor: a streak of light in the sky.
Because of their appearance, these streaks of light are sometimes called “shooting stars.”
But meteors are not actually stars.
Meteors are also different from comets, even though the two are sometimes confused.
Comets: ice and dust, not rock
Comets orbit the Sun, like asteroids.
But comets are made of ice and dust — not rock.
As a comet’s orbit takes it toward the Sun, the ice and dust begin to vaporize.
That vaporized ice and dust become the comet’s tail.
You can see a comet even when it is very far from Earth.
However, when you see a meteor, it is in our atmosphere.
Meteorites: pieces that land
Sometimes meteoroids do not vaporize completely in the atmosphere.
Sometimes they survive their trip through Earth’s atmosphere and land on Earth’s surface.
When they land on Earth, they are called meteorites.
NASA’s Johnson Space Center has a collection of meteorites that have been collected from many different locations on Earth.
The collection acts as a meteorite library for scientists.
By studying different types of meteorites, scientists can learn more about asteroids, planets, and other parts of our solar system.
Clues from nearly 4.6 billion years ago
Asteroids formed in the early days of our solar system, nearly 4.6 billion years ago.
Because of that, meteorites can give scientists information about what the solar system was like way back then.
Words to know
- Asteroid
- A small rocky body that orbits the Sun. Asteroids are smaller than a planet, but larger than the pebble-size objects called meteoroids.
- Meteoroid
- A small piece that breaks off when one asteroid smashes into another. Meteoroids can also come from comets. A meteoroid is also the small piece of an asteroid or comet that can become a meteor.
- Meteor
- What happens when a meteoroid comes close enough to Earth, enters Earth’s atmosphere, and vaporizes: a streak of light in the sky. These streaks are sometimes called “shooting stars,” but meteors are not actually stars.
- Meteorite
- A meteoroid that does not vaporize completely, survives its trip through Earth’s atmosphere, and lands on Earth’s surface.
- Comet
- An object that orbits the Sun, like an asteroid, but is made of ice and dust — not rock. As its orbit takes it toward the Sun, the ice and dust vaporize and become its tail.
- Orbit
- The path an object follows as it goes around the Sun. Some asteroid orbits take them near Earth, and a comet’s orbit takes it toward the Sun.
You can also read the page called “What Is a Meteor Shower?”
Sources
This page was built only from this source:
NASA Space Place — “Asteroid or Meteor: What’s the Difference?” — https://spaceplace.nasa.gov/asteroid-or-meteor/en/
Checked November 2, 2026.