AROUND 4 BILLION YEARS AGO, LIFE BEGAN EMERGING ON EARTH in the form of microorganisms. Whether or not life originated on our planet, or was somehow transported there by way of a traveling asteroid, is one of the biggest questions in astronomy.

Now, a new experiment favors the idea that life ended up on our planet after a long journey through space — by proving that bacteria can in fact survive the trip.

Scientists conducted an experiment onboard the International Space Station that supported the controversial theory of panspermia.