Dinosaur asteroid 'sent life to Mars'
The asteroid that wiped out the dinosaurs may have catapulted life to Mars and the moons of Jupiter, US researchers say.
They calculated how many Earth rocks big enough to shelter life were ejected by asteroids in the last 3.5bn years.
The Chicxulub impact was strong enough to fire chunks of debris all the way to Europa, they write in Astrobiology.
Thousands of potentially life-bearing rocks also made it to Mars, which may once have been habitable, they add.
"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.
"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."
Panspermia - the idea that organisms can "hitchhike" around the solar system on comets and debris from meteor strikes - has long fascinated astronomers.
But thanks to advances in computing, they are now able to simulate these journeys - and follow potential stowaways as they hitch around the Solar System.
In this new study, researchers first estimated the number of rocks bigger than 3m 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 fate of these voyagers. Many simply hung around in Earth orbit, or were slowly drawn back down.
Others were pulled into the Sun, or sling-shotted out of the Solar System entirely.
Yet a small but significant number made it all the way to alien worlds which might welcome life. "Enough that it matters," Ms Worth told BBC News.
About six rocks even made it as far as Europa, a satellite of Jupiter with a liquid ocean covered in an icy crust.
"Even using conservative, realistic estimates... it's still possible that organisms could be swimming around out there in the oceans of Europa," she said.
Travel to Mars was much more common. About 360,000 large rocks took a ride to the Red Planet, courtesy of historical asteroid impacts.
Big bang theory
Perhaps the most famous of these impacts was at Chicxulub in Mexico about 66 million years ago - when an object the size of a small city collided with Earth.
The impact has been blamed for the mass extinction of the dinosaurs, triggering volcanic eruptions and wildfires which choked the planet with smoke and dust.
It also launched about 70 billion kg of rock into space - 20,000kg of which could have reached Europa. And the chances that a rock big enough to harbour life arrived are "better than 50/50", researchers estimate.
But could living organisms actually survive these epic trips?
"I'd be surprised if life hasn't gotten to Mars," Ms Worth told BBC News.
"It's beyond the scope of our study. But it seems reasonable that at some point some Earth organisms have made it over there."
They calculated how many Earth rocks big enough to shelter life were ejected by asteroids in the last 3.5bn years.
The Chicxulub impact was strong enough to fire chunks of debris all the way to Europa, they write in Astrobiology.
Thousands of potentially life-bearing rocks also made it to Mars, which may once have been habitable, they add.
"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.
"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."
Panspermia - the idea that organisms can "hitchhike" around the solar system on comets and debris from meteor strikes - has long fascinated astronomers.
But thanks to advances in computing, they are now able to simulate these journeys - and follow potential stowaways as they hitch around the Solar System.
In this new study, researchers first estimated the number of rocks bigger than 3m 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 fate of these voyagers. Many simply hung around in Earth orbit, or were slowly drawn back down.
Others were pulled into the Sun, or sling-shotted out of the Solar System entirely.
Yet a small but significant number made it all the way to alien worlds which might welcome life. "Enough that it matters," Ms Worth told BBC News.
About six rocks even made it as far as Europa, a satellite of Jupiter with a liquid ocean covered in an icy crust.
"Even using conservative, realistic estimates... it's still possible that organisms could be swimming around out there in the oceans of Europa," she said.
Travel to Mars was much more common. About 360,000 large rocks took a ride to the Red Planet, courtesy of historical asteroid impacts.
Big bang theory
Perhaps the most famous of these impacts was at Chicxulub in Mexico about 66 million years ago - when an object the size of a small city collided with Earth.
The impact has been blamed for the mass extinction of the dinosaurs, triggering volcanic eruptions and wildfires which choked the planet with smoke and dust.
It also launched about 70 billion kg of rock into space - 20,000kg of which could have reached Europa. And the chances that a rock big enough to harbour life arrived are "better than 50/50", researchers estimate.
But could living organisms actually survive these epic trips?
"I'd be surprised if life hasn't gotten to Mars," Ms Worth told BBC News.
"It's beyond the scope of our study. But it seems reasonable that at some point some Earth organisms have made it over there."
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