Ancient Meteorites

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The oldest objects on Earth didn’t come from our home planet. They were born in space more than four-and-a-half billion years ago. They fell to Earth as the most common type of meteorite. Chondrites account for about 85 percent of all meteorites. They’re named for tiny round beads of material known as chondrules. The beads formed in the disk of gas and dust that encircled the newborn Sun. Grains of dust clumped together. The chondrules then mixed in with other particles to form asteroids. Collisions sent pieces of the asteroids racing off into space. Some of them plunged through Earth’s atmosphere, falling as meteorites. Chondrites haven’t changed much since they formed, so they preserve a…