The History of Earth: BOMBARDMENT
There are millions of asteroids that could cause our planet serious damage. And occasionally they do. Welcome to Part 7 of the History of Earth.
On 30 June 1908, a meteorite 50 to 60 metres wide approached Earth at a speed of 100,000 km/h.
It exploded at an altitude of 5 to 10 kilometres above a remote region of Siberia with the force of 3 to 5 megatons (and, according to some calculations, up to 30 megatons).
That’s 200 to 2,000 times the force of the bomb at Hiroshima.
It flattened an estimated 80 million trees over a 2,150 km2 area, equivalent to the combined area of Los Angeles and New York.
It became known as the Tunguska event and it was the largest meteorite impact in recorded history.
The shock wave smashed windows hundreds of miles away.
Now for the bad news.
In the asteroid belt, there are around 1.5 million asteroids larger than a kilometre in diameter, and many millions the size of the one in the Tunguska event. Any one of these could fall out of orbit and head towards us.
These things happen.
