Astronomers have found that the majority of meteorites that regularly fall into Earth's atmosphere today are the result of an asteroid collision that took place 466 million years ago. Using chemical analysis from rock samples around the world, the team discovered that before that colossal collision, Earth experienced impacts from many different types of meteorite, meaning that our planet's history with meteorites is far more complex than we thought. After examining the chemical makeup of these chrome-spinels, the team found that 34 percent of the pre-collision micrometeorites were primitive achondrites, a type of meteorite that only makes up 0.45 percent...