A 22-Million-Year Journey From the Asteroid Belt to Botswana

Astronomers reconstructed a space rock’s path before it exploded over southern Africa in 2018 and sprinkled the Kalahari with meteorites.

On the morning of June 2, 2018, an asteroid was seen careening toward us at 38,000 miles per hour. It was going to impact Earth, and there was nothing anyone could do to stop it. Astronomers were beside themselves with excitement. Five feet long and weighing about the same as an adult African elephant, this space rock posed no threat. But the early detection of this asteroid, only the second to be spotted in space before hitting land, was a good test of our ability to spot larger, more dangerous asteroids. Moreover, it afforded scientists the chance to study the asteroid before its obliteration, quickly narrow down the impact site and obtain some of the most pristine, least weathered meteorite samples around. Later that day, a fireball almost as bright as the sun illuminated Botswana’s darkened sky before exploding 17 miles above ground with the force of 200 tons of TNT. Fragments fell like extraterrestrial buckshot into a national park larger than the Netherlands.