It's one thing for a tree to make no sound when it falls in a forest -- or does it? -- but what about an enormous meteorite leaving no crater when it falls to Earth? That's what happened with the Hoba meteorite, thought to be the largest known meteorite ever to plummet from the sky. The Hoba meteorite -- named after the farm in Namibia where it was discovered in 1920 -- weighs around 66 tons (60 tonnes), but it was hardly noticeable at first, as it was only a black mark in an otherwise chalky field. After excavation, the meteorite was found to be composed of 84 percent iron and 16 percent nickel, having fallen to Earth some 80,000 years ago. As for why it created such a small crater upon impact, scientists can only speculate that it slowed to terminal velocity after passing through Earth's atmosphere, possibly helped by its flat shape. Today, the meteorite remains exactly where it was discovered nearly 100 years ago.
It fell from the sky:
- "Shooting stars" are actually meteors burning up as they enter Earth's atmosphere.
- The Perseids are a meteor shower that can be seen every year in mid- to late summer.
- As many as 4 billion meteoroids fall towards the Earth every day, but most are too small to see.