New study reveals how space rocks become meteorites

A new study reveals how space rocks become meteorites, identifying seven distinct phases in their journey from space to Earth. Researchers analyzed 75 meteorite falls and found that melting and fragmentation, rather than simple evaporation and burning up, control how rocks lose mass and slow down. The study shows that a fireball goes through seven stages, each shaped by different physical processes. The fastest-spinning rocks in the study made a full turn every 0.5 to 5 seconds. The team found that melting causes most of the rock's mass loss, with some rocks losing up to 40% of their mass from melting. The study also highlights that rocks break apart when the air pressure in front of them is only about one-fifth of the strength measured in meteorites found on Earth. The researchers believe that heat and cracks from earlier collisions in space explain why rocks break earlier than expected. The study provides insight into how larger asteroids, up to tens of meters in size, behave during atmospheric entry. The 20-m-diameter asteroid that caused the airburst over Chelyabinsk, Russia, in 2013, went through the same phases. The findings suggest that understanding how small space rocks behave can help predict how larger asteroids, like those up to city blocks in size, behave during atmospheric entry. The study was published in the journal Meteoritics & Planetary Science.

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