Last week was the 100th anniversary of the Tunguska explosion in Siberia. If you weren’t celebrating, you should have been. The incident was probably the nearest we have come to extinction in modern human history – and we survived.

A large object – presumably an asteroid or meteorite – collided with the Earth. If it had landed in Manhattan, it would have destroyed New York. A bit bigger, and it would have been calamitous wherever it landed. A similar event at Yucatan, 65m years ago, wiped out the dinosaurs and most other species. It would have wiped us out too had we been there. We survived Tunguska because the impact was not too large.