We discover an asteroid is on collision course with Earth - what next? How do countries, space agencies and other bodies work together to defend Earth? As Romana Kofler from the United Nations Office for Outer Space Affairs explains, that's where the UN steps in.
Asteroids can tell us about the origins of the Solar System and maybe even life itself, but they also pose a risk to Earth as many graze past our planet on a regular basis. Find out more about what ESA is doing to protect us through its Planetary Defence Office, part of the Space Safety programme.