How do you stop a mid-sized asteroid hurtling towards Earth? NASA planetary defence officer, Kelly Fast, says small space rocks hit earth regularly, but bigger rocks, of at least 140m in diameter, could cause significant regional damage. Kelly’s with Jim to discuss the threat of an asteroid impact, ways of deflecting them and how NASA spots and keeps track of space rocks.
A computer illustration of an asteroid. Photo: ANDRZEJ WOJCICKI / AFP
