Frequently Asked Questions
In this section we'd like to answer some frequently asked questions concerning meteorites. If you don't find your question here, feel free to contact us - it's our pleasure to provide you with additional information!
What is a meteorite?
A meteorite is an actual piece of extra-terrestrial matter that has reached the surface of our planet, Earth.
Sometimes the term "meteorite" is confused with two related terms -
"meteoroid" and "meteor". A meteoroid is a small object that
orbits the Sun near the Earth - the precursor of a meteorite before it enters the atmosphere. Upon entering the Earth's atmosphere, it produces a bright streak of light in the sky, a phenomenon known as
a "shooting star", or a "meteor". However, most meteors do not produce any meteorites because they stem from tiny particles burning up completely in the atmosphere. Only larger chunks of matter finally make it to the ground, producing extremely bright
meteors known as "fireballs", or "bolides".
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Where do meteorites come from?
Most meteorites have their origin in the asteroid belt, a region between Mars and Jupiter, where many thousands of large and small asteroids orbit the Sun. Through
collisions and gravitational forces, pieces of these asteroids are sometimes pulled into an Earth-crossing orbit, finally reaching the ground in
the form of a meteorite. However, some rare types of meteorites have proven to
have different origins. Today, we know of several meteorites that are pieces of the Moon and the planet Mars. Some other rare meteorites are suspected
to have a cometary origin. For further information, have a look at our Origins
page. >>
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How do we know that some meteorites are from the Moon?
When it comes to lunar meteorites, the answer is easy: we have been to the Moon, and we have returned samples for comparison. Chemical and mineral compositions, isotope ratios, and textures of lunar meteorites, are similar to those of samples collected on the Moon during the Apollo and Luna missions. Taken together, these characteristics differ from those of any other type of meteorite or terrestrial rock, so that we can say for sure: Yes, these meteorites are genuine
lunar rocks.
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How do we know that some meteorites are from
Mars?
When it comes to Martian meteorites, we haven't returned any samples thus far. However, the Viking and Pathfinder probes have provided enough data to justify this conclusion. Some Martian meteorites were found to contain trapped gas-inclusions
that perfectly match the composition of the Martian atmosphere, but are distinct from our own.
Several other characteristics are consistent with a Martian origin for these rare meteorites - have a look at our
Mars meteorite page.
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What are meteorites composed of?
The most common meteorites from the asteroid belt are stony meteorites, called chondrites,
which are primarily composed of olivine, different types of pyroxene, and nickel-iron metal. Their mineral compositions
have remained more or less unaltered since the time of the formation of our solar system, and hence, they can be regarded as genuine primordial matter. Other, less common,
meteorite types were subjected to a process of differentiation, a fact that is reflected in their mineral compositions. Their parent bodies developed a nickel-iron core, a stony-iron
mantle, and a stony crust. Hence, meteorites that stem from the core of a differentiated asteroid are composed of different alloys of nickel-iron, and they are usually
referred to as iron meteorites. Meteorites from the mantle of a differentiated asteroid
often have a stony-iron compostion, while those from the crust have stony compositions, often resembling terrestrial rocks. Have a look at our
Classification section for additional information.
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