US RESEARCHERS say the asteroid that wiped out the dinosaurs may have catapulted life to Mars and the moons of Jupiter.
Researchers started by estimating the number of rocks bigger than 3 metres ejected from Earth by major impacts. (Three metres is the minimum they think necessary to shield microbes from the Sun's radiation over a journey lasting up to 10 million years.)
They then mapped the likely trajectory. Many hung around Earth, some were pulled into the Sun, or flung out of the Solar System.
The researchers predict that about six rocks even made it as far as Europa, a satellite of Jupiter, and about 360,000 large rocks made it to Mars.
"We find that rock capable of carrying life has likely transferred from both Earth and Mars to all of the terrestrial planets in the solar system and Jupiter," says lead author Rachel Worth, of Penn State University.
Panspermia is the idea that organisms can "hitchhike" around the solar system on comets and debris from meteor strikes but now thanks to advances in computing, researchers can now map these journeys.
"It's beyond the scope of our study. But it seems reasonable that at some point some Earth organisms have made it over there."