The comet-chasing mission of ESA spacecraft Rosetta and its robotic lander Philae has grabbed attention from around the world with its suspenseful adventures. The science behind the mission is just as fascinating, and could help unlock secrets on how our solar system formed billions of years ago.

In 2004, Rosetta the spacecraft and Philae the robot set out on a mission to catch a distant comet called 67P/Churyumov-Gerasimenko.

What they are now doing over a decade later is re-writing, in surprising new ways, our understanding of how the solar system formed.