Mind-bogglingly fast streams of inter-planetary dust which continually bombard Earth’s atmosphere could have delivered tiny organisms from far-off worlds, or send Earth-based organisms to other planets, according to the research.
And one of the favourite options for that tiny organism is the seemingly indestructible tardigrade.
The hideously ugly tardigrade, which has eight legs with claws at the end, a brain and central nervous system, has already been credited with the ability to outlive humans by 10 billion years (according to a recent study from Oxford University).
Now they are a front-runner for actually bringing life to Earth.
Tardigrades have been recorded as going into a form of suspended animation for 30 years – without any water – before springing back to life.
Their longevity in suspended animation is unknown.
Although interstellar distances are astronomical the space winds on which the microbes travel are also impossibly fast – and have been recorded at 252,000 kph.
At that speed it would take less than 20 years to approach our nearest stellar neighbour Alpha Centauri.
Research at the University of Edinburgh calculated how the powerful flows of space dust could collide with particles in our atmospheric system.
They concluded the method could enable bacteria and other forms of life to make their way from one planet in the solar system to another and perhaps beyond.
The team found that small particles existing at 150 km or higher above Earth’s surface could be knocked beyond the limit of Earth’s gravity by space dust and eventually reach other planets.
The same mechanism could enable the exchange of atmospheric particles between distant planets.
Bacteria, plants and especially tardigrades are known to be able to survive in space, so it is possible that such organisms might collide with fast-moving space dust and withstand a journey to another planet.
The study was published in Astrobiology, was partly funded by the Science and Technology Facilities Council.
Professor Arjun Berera, from the University of Edinburgh’s School of Physics and Astronomy, who led the study, said: “The proposition that space dust collisions could propel organisms over enormous distances between planets raises some exciting prospects of how life and the atmospheres of planets originated.
“The streaming of fast space dust is found throughout planetary systems and could be a common factor in proliferating life.”