Why are we on Earth, but the T-rex isn't? Could we face the same fate as the dinosaurs? Find out from Alan Fitzsimmons, Professor at Queen's University Belfast, who comes bearing good news.

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.

Access the other "Asteroid Day selfies"