An accidental discovery
In 1920, a farmer named Jacobus Hermanus Brits was plowing a field on his farm, Hoba West, when his ox-drawn plow came to an abrupt halt with a loud metallic screech. The obstruction was a massive, flat-topped black rock. Brits scratched the surface with his knife and saw a metallic shine underneath. He had discovered what is now known as the Hoba meteorite, the largest single meteorite ever found on Earth and the massive naturally occurring piece of iron on the planet's surface.
Because of its immense weight, estimated at over 60 tonnes, the meteorite has never been moved from where it landed. The object measures roughly 2.7 by 2.7 meters, with a thickness of about 0.9 meters. A puzzling feature of the discovery is the complete absence of an impact crater. Scientists theorize that the meteorite's unusually flat, tabular shape caused it to enter Earth's atmosphere at a very shallow angle. This would have slowed its descent dramatically, allowing it to land at terminal velocity without causing a significant excavation.
A rare metallic composition
The Hoba meteorite is classified as an ataxite, a rare type of iron meteorite with a high nickel content. Its composition is approximately 84% iron and 16% nickel, with traces of cobalt and other metals. This specific nickel concentration prevents the formation of the Widmanstätten patterns, a crystalline structure common in other iron meteorites, which are revealed when they are etched with acid. The meteorite's material is estimated to be between 190 and 410 million years old, though its impact with Earth occurred much more recently, less than 80,000 years ago.
To protect it from vandalism and sampling, the government of what was then South West Africa declared the meteorite a national monument on March 15, 1955. In 1987, the owner of the farm donated the site to the state for educational and tourism purposes. A circular stone amphitheater was later built around the meteorite, allowing visitors to view this extraterrestrial object up close.