"An asteroid this size impacts Earth on average every few thousand years and could cause severe damage to a local region," the European Space Agency said.

you basically wipe out the whole city and some of the environs,” said Betts. The best modern comparison is the 1908 Tunguska Event when an asteroid or comet fragment measuring 30-50 metres ...

but a newly detected asteroid nearly the size of a football field now has a greater than one percent chance of colliding with Earth in about eight years. Such an impact has the potential for city ...