Has life from Earth spread to other planets?
Researchers at the Kyoto Sangyo University in Japan have released a study showing how life-bearing meteorites from Earth could have spread around our galaxy after a massive asteroid impact 65 million years ago.
The asteroid that created the Chicxulub crater in Mexico could have ejected as much mass from Earth as the asteroid itself. While much of the mass ejected would have ended up on the Moon, almost the same amount is thought to have landed on Europa. That’s because the gravitational field for Jupiter draws in anything passing by, where it can be swept up by orbiting planets.
Estimates for the number of Earth rocks on our Moon and Europa are as many as 100,000,000 individial rocks on each planet. While it’s not known if microbes would be able to survive that long journey and seed life on other planets, there are many planets that would easily support them if they did make the journey intact. For example, a super-Earth planet orbiting star Gliese 581 is thought to have attracted up to 1,000 rocks from the Earth impact event. The journey there would have taken around 1 million years, meaning that if any Earth microbes made the trip, they’ve had 64 million years to evolve.