In 2013, the skies lit up over the Russian city of Chelyabinsk, as a small asteroid struck Earth's atmosphere. It didn't reach the ground, yet people were still hurt. Olga Ramírez, former trainee at ESA's Planetary Defence Office, explains.
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.