In the news recently it's been said that in 2029 the asteroid called Apophis, aka 'The God of Chaos', will fly by very close to earth. To quote Geek.com
In 2029, a massive asteroid called 99942 Apophis will fly past our planet at an approximate distance of 19,000 miles within the distance of some orbiting spacecraft.
It's said the chances of a collision are about 1 in 100,000, which is small but not not completely infeasible either.
The asteroid has a diameter of around 350 meters with a mass of 4×10^10 kg and an average orbital speed of around 30km/s.
What kind of damage could we expect on earth if it were to collide with us?