What happens to a space rock as it falls through Earth’s atmosphere and becomes a meteorite? By studying 75 meteorite falls captured on video and in photographs, researchers identified seven distinct phases in the journey from space rock to meteorite. Their findings show that melting and fragmentation, rather than simply evaporation and “burning up,” control how a rock loses mass, slows down and ultimately reaches the ground. The journal Meteoritics & Planetary Science published these findings.

“We used to think that solid rocks would evaporate from the enormous heat and brilliant light generated in collisions with air,” said meteor astronomer and lead author Dr. Peter Jenniskens of the SETI Institute and NASA Ames Research Center. “We found instead that first melting and then fragmentation control how a rock loses mass.”

The team found that a fireball goes through seven stages as it moves through Earth’s atmosphere. Each stage is shaped by different physical processes.