Each year, thousands of space rocks pierce through the Earth’s atmosphere and hit the ground as meteorites. These fragments of comets and asteroids can land anywhere but are most often spotted in open terrain, such as the deserts of Africa and the Antarctic blue ice, where a meteorite’s blackened exterior can stand out. Still, these extraterrestrial remnants can resemble Earth rocks, and to tell the difference meteorite hunters often expose their “finds” to hand magnets, which can attract more strongly to metal-rich meteorites than to terrestrial rocks. Meteorite hunters, dealers,…