Researchers calculated the number of rocks that could have been dispersed into space after the asteroid impact at Chicxulub in Mexico about 66 million years ago. According to their findings, published in the journal Astrobiology, nearly 70 billion kilograms of rocks were launched into space, with around 20,000 kilograms of rocks reaching Europa.
The researchers only considered rocks 3 meters or larger in diameter, as smaller rocks would be unable to protect the organisms from the sun's radiation. They used computer simulations to predict the trajectory of these rocks, and how these organisms may have hitched a ride across the solar system.
"Any missions to search for life on Titan or the moons of Jupiter will have to consider whether biological material is of independent origin, or another branch in Earth's family tree," said lead author Rachel Worth, of Penn State University.
Panspermia, an idea that has fascinated scientists for years, is the travel of organisms around the solar system on comets and debris from meteor strikes.
While many of these rocks orbited Earth or were slowly pulled back to its surface, others were attracted toward the sun or were slingshot across our solar system. Scientists believe 360,000 rocks reached Mars and only 6 reached Europa.
And the chances that life survived these journeys, scientists say, is 50 percent.
While it was beyond the scope of the study, Worth said that it was highly likely that some of the organisms survived space travel. The most hospitable of planets and moons would have to be Europa, Mars and Titan, a moon of Saturn -- all three at some point in time held water.
"I'd be surprised if life hasn't gotten to Mars," said Worth.