How Earthly life could populate space by panspermia
Lisa Grossman, reporter
(Image: D. Van Ravenswaay/SPL/Getty)
For years, scientists have imagined that microbial life may have ridden to Earth on the back of a comet or meteorite, planting the seed for the diversity of life we know today. But could so-called panspermia have gone the other way? Could Earth have given other worlds life?
It's an old idea, but Tetsuya Hara of Kyoto Sangyo University in Japan and colleagues now have new calculations suggesting it's possible. "The only planet which we know has life is Earth," they write in a paper posted to the arXiv physics preprint site. "Therefore, Earth would be a likely source to seed other planets with life."
Microbes could be knocked out of the atmosphere into space by high-speed ions after a solar storm, but without protection, the microbes would be irradiated to death by those same charged particles.
Perhaps a safer way for seed to spread would be for whole rocks to travel other worlds. Previous research has showed that, theoretically, a massive meteorite impact could blast up and scatter tonnes of rock across the solar system.
Sorry, no citation. It was discussed on Skeptics' Guide to the Universe podcast. One interesting finding was that Europa might be safe from a panspermian event from Earth. Why? Apparently the gravity well of Jupiter might make a collision of Earth rocks too energetic for microbes to survive. I haven't heard more about this, but it's a interesting topic and this new research poses some fascinating possibilities.
I especially like the calculations about Gliese 581. It suggests that life on Earth could also have been seeded from space.