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 meters ...

An asteroid that's big enough to wipe out a city has a 1-in-43 chance of hitting our planet in the year 2032. But according to new calculations, there's an even smaller chance that it might crash ...

Experts warn the "city-killer" asteroid has the potential to do "serious ... to plunge the planet into an "impact winter," creating food scarcity and devastating ecosystems for years after impact ...