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Meteoroid

Adapted from Wikipedia · Discoverer experience

The Crab Nebula is a beautiful glowing cloud of gas and dust formed when a star exploded long ago. This amazing picture shows the colorful remains of the explosion taken by a space telescope.

A meteoroid is a small piece of rock or metal that floats in outer space. These tiny space rocks are much smaller than asteroids, usually ranging from the size of a grain of sand up to about as big as a basketball. Even smaller pieces are called micrometeoroids or space dust.

A meteoroid shown entering the atmosphere, causing a visible meteor and hitting the Earth's surface, becoming a meteorite

Many meteoroids come from comets or asteroids that have broken apart. Others are bits of rock thrown into space by collisions on planets like the Moon or Mars.

When a meteoroid enters Earth's atmosphere, it glows brightly and we call this a meteor. If many meteors appear together in the night sky, coming from the same point, we call this a meteor shower. Each day, about 25 million meteoroids and pieces of space junk enter our atmosphere, adding up to around 15,000 tonnes of material each year. If any part of a meteoroid survives the trip through the atmosphere and lands on the ground, it is called a meteorite.

Meteoroids

See also: Micrometeoroid

Meteoroid embedded in aerogel; the meteoroid is 10 μm in diameter and its track is 1.5 mm long

A meteoroid is a small solid piece of rock or metal that travels through space. It is much smaller than an asteroid but bigger than a tiny speck of dust. These objects can range in size from tiny grains to about as big as a human being.

Most meteoroids come from the area between the planets, called the asteroid belt, or from comets—big balls of ice and dust that orbit the Sun. When these meteoroids enter Earth’s atmosphere, they heat up and glow, creating what we call a shooting star or meteor. If any part of the meteoroid makes it all the way to the ground, it is called a meteorite.

Frequency

Every day, Earth is likely hit by a space rock about 40 cm (1 foot 4 inches) big. Once a year, something around 4 meters (13 feet) could strike, and every century, an object about 20 meters (66 feet) might hit us. About 35 to 40 objects that are 1 meter (3 feet) or larger enter our atmosphere each year, which means roughly one every 10 days.

Scientists use a special formula to figure out how many impacts happen each year based on the size of the object. The formula helps them understand these space rocks better.

Meteorites

Main article: Meteorite

A meteorite is a piece of a space rock that makes it through Earth's air and lands on the ground. Not all space rocks that hit Earth leave behind meteorites, because sometimes they turn into gas during impact and disappear.

Space rocks also crash into other places in our solar system. On places like the Moon or Mars, which don't have much air, these crashes leave behind lasting marks called craters.

Murnpeowie meteorite, an iron meteorite with regmaglypts resembling thumbprints (Australia, 1910)

Impact craters

Main article: Impact crater

When space rocks crash into solid objects in space, like the Moon or Mars, they create craters. These craters are common on many of these objects. On planets like Earth, some of these craters may disappear over time because of natural changes in the surface.

Gallery of meteorites

Two special rocks called tektites, made from Earth material thrown into the air by a space rock crash

A piece of the Esquel space rock

Willamette space rock, from Oregon, US

Space rock that fell in [Wisconsin](/wiki/Wisconsin) in 1868

[Marília](/wiki/Marília) space rock, a common type of space rock, which fell in Marília, Brazil (1971)

Children standing behind a copy of the Tucson space rock at the [Arizona Museum of Natural History](/wiki/Arizona_Museum_of_Natural_History)

Space rock with special patterns and [carbon](/wiki/Carbon) pieces from [Tindouf](/wiki/Tindouf), Algeria

Images

A meteorite fragment discovered in the Nubian Desert, showing scientists' exploration of space materials.
Tektites are small, natural glass objects formed when meteorites strike the Earth. They often have interesting shapes like dumbbells and teardrops.
A slice of the Esquel meteorite, showing its unique structure, on display at the Canadian Museum of Nature.
A large meteorite displayed at the American Museum of Natural History in New York City.
A meteorite found in Marília, Brazil, showcasing a fascinating piece of space history.
Kids admiring a meteorite replica at the Arizona Museum of Natural History.
A meteorite sample from Algeria, showing interesting rock patterns formed during its journey through space.
A collection of images of planets in our solar system taken by NASA spacecraft, showing Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, and Neptune.
A stunning view of our planet Earth as seen from the Apollo 17 spacecraft during its journey to the Moon.
A meteorite specimen known as the Trenton meteorite, showcasing the fascinating materials that fall from space.

Related articles

Moon
Mars
Meteorite
Outer space
Meteor shower
Asteroid

This article is a child-friendly adaptation of the Wikipedia article on Meteoroid, available under CC BY-SA 4.0.

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