What is the most common type of meteorite to fall?
Ordinary chondrites, especially L and H types, make up about four out of five witnessed falls.
When scientists look at falls, meteorites seen to fall and then collected, they get the fairest picture of what reaches Earth today, because falls are not biased towards meteorites that are easy to find.
Among falls: - Ordinary chondrites make up roughly 80 per cent. L chondrites are the most common single group, closely followed by H chondrites, with LL chondrites less common. - Carbonaceous chondrites make up about 4 to 5 per cent, but many probably break up in the atmosphere, so they may be under-represented. - Achondrites make up roughly 8 per cent, with HED meteorites from Vesta the most common. - Iron meteorites make up about 4 to 5 per cent. - Stony-irons make up about 1 per cent. - Enstatite chondrites make up about 1 to 2 per cent.
Among finds, the proportions differ. Iron meteorites are much more common among finds outside deserts, because they look unusual and survive weathering. Antarctic and desert finds have their own biases.
Why are L and H chondrites so common? Research published in 2024 linked many L chondrites to the Massalia family of asteroids in the inner belt, created by a collision about 470 million years ago, and many H chondrites to young families such as the Karin cluster within the Koronis family. Their position near resonances with Jupiter and Saturn makes them efficient suppliers. The mix of falls changes slowly over geological time as new asteroid families form and old ones are depleted.
More about the science of meteorites
- Do meteorites contain sugars or DNA building blocks?
- How do scientists stop meteorites being contaminated?
- Why are witnessed falls more useful to science than finds?
- What happens to a meteorite as it weathers on Earth?
- Can micrometeorites tell us about Earth's ancient atmosphere?
- What are cosmic spherules?