'Obviously the threat is there': Chris Hadfield on the danger of asteroid strikes

As June 30th is annouced as Asteroid Day 2017, astronaut Hadfield explains why we should take the possibility of collisions with celestial rocks seriously

• Watch the Asteroid Day press conference live here at 13.30GMT

"The Earth gets hit by 50 tonnes of meteorites a day. That's more than most people think. Normally they are small little grains and burn up but once in a while they are big rocks," says astronaut Chris Hadfield, who launched himself to stardom by singing David Bowie's Space Oddity on the International Space Station.

"Occasionally they go over an inhabited part of the world and we see a shooting star. Or they get close to the ground like Chelyabinsk and they do damage. So obviously the threat is there. Obviously," he says.