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Meteors streak through the air giving us a display that can be not only beautiful but awe-inspiring as well. This isn’t all they give us as they carry to us a wealth of information from the solar system.

So what is flying through the atmosphere giving us a such a show? As you might imagine the meteors are debris from the solar system such as fragments of asteroids that probably broke off during a collision between two asteroids or from meteoroids.

There are three different definitions of dust and debris that fly towards the Earth through the atmosphere-

• A meteoroid is an object moving in interplanetary space smaller than an asteroid but larger than an atom, this can obviously include dust or ice from a comet or other fragments or dust.
• A meteor is a Meteoroid that has entered the Earth’s atmosphere and is producing a streak of light as it burns up.
• A meteorite is a meteor that has actually struck the ground.

There are things called meteor showers that I’ve talked about before in recent posts and these are just a lot of meteors falling to Earth giving us a light show. You will have the image, when talking about meteors, of a ball of fire streaking to Earth and then creating havoc destroying towns and cities. That is not so when you get further into the subject of meteors. Meteors can be very, very small and are then called Micrometeors.

Fireball

These can be as small as atoms and dust and drift down over months to the surface of the Earth. If you are standing outside for a few hours you will probably be hit by one of these particles. It didn’t hurt though did it? That’s because the smallest atoms or particles get slowed down by the frictional drag of the atmosphere and lose the velocity they had in interplanetary space.

Meteorites come from all over the solar system bringing us all sorts of information from their makeup. Scientists classify the meteorites into three types depending on what they are made of-

• Iron meteorites which are mostly made of iron. These make up around about 5% of all meteorites and are between 10 to 40 kg.
• Stony meteorites which are made up of silicate minerals. These make up around about 94% of all meteorites and are about 1 to 10 kg.
• Stony-iron meteorites are a mixture of both and are made up of metals and silicates. These make up the remaining 1% of meteorites that are found on the surface of the Earth.

Meteorites have become very precious because of their rarity and scientists have a hard time finding original samples. They use a network of trusted people to get samples to test. Because of this and because the Earth is covered in all sorts of rocks and metals there are not so many meteorites found as actually fall to the Earth.

One of the best ways of finding samples is to actually see a meteor hit the ground and then go to the impact site. When a meteorite has been seen to fall to earth it is called a meteorite fall and the best finds have been found in this way. When a meteorite has been found and was not seen to fall to earth as a meteor it is called a meteorite find. Large meteorites are mostly found with meteorite finds the largest being Hoba.

Hoba

So once meteors have hit the ground creating meteorites what information can they give us?

The most interesting information comes from things called chondrites. About 86% of the meteorites that fall on Earth contain these small round particles. They are mostly made up from silicate minerals that have been melted while they were floating around in space. They are very old and date back from the origins of the solar system.

Chondrite

They are thought to have escaped the collisions which created the planets and to contain the building blocks of the solar system. Knowing what the building blocks of the solar system were gives us a good picture of how the solar system was created and the composition of different planets other than Earth.

Achondrites are meteorites that do not contain chondrites. They are useful though as they contain rocks that are similar to igneous rocks. They are thought to contain the crustal material of asteroids and some of these chondrites have been brought back from the moon.

As you can see meteorites give us a picture of how the solar system was formed although we could still do with rocks from all the different planets. Unfortunately though, this is probably the best we will get for some time.

If you’d like a free poster to download about Canadian meteorites then try this poster. While you are clicking links you might as well try this in database from the Natural History Museum and find out how many meteorites have hit your country. Just in case you aren’t asleep yet here’s a very good site on meteorites.

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