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Some scientists believe alien life was transported to Earth on a comet - a theory known as panspermia.

But if alien life can travel between planets, the opposite may also be true, and parts of Earth could be 'seeding' life elsewhere in the solar system.

The theory has gained traction over the past few years, with scientists claiming that the asteroid that wiped out the dinosaurs took Earth-life to Mars and the moons of Jupiter.

Some scientists believe alien life was transported to Earth on a comet. But if alien life can travel between planets, the opposite may also be true, and Earth could be 'seeding' life elsewhere in the solar system

In a paper last year, Rachel Worth, a PhD candidate at Penn State University said that it's likely that life from Earth has already been brought to other planet.

Ms Worth's team first looked at the number of rocks bigger than 9.8ft (3 metres) that were thrown out to space from Earth by major impacts, according to a report by Maddie Stone in Motherboard.

The size of rock would shield microbes from the sun's radiation over a journey across the solar system.

Using computer simulations, the team then mapped the fate of these rocks.

While many didn't survive the journey, thousands of rocks hit Mars and about six rocks made it as far as Europa, a moon of Jupiter with an icy crust.

In a paper last year, Rachel Worth, a PhD candidate at Penn State University said that it's likely that life from Earth has already been brought to other planet, such as Mars (pictured)

'At the end of the day, it's not the numbers themselves that matter, but the order of magnitude,' Ms Worth told Motherboard.

'If the numbers were much lower than one, we'd assume this event is unlikely to have occurred since the origin of life on Earth.

'But one to ten impacts over the last several billion years tells us we can't rule out the possibility of life from Earth seeding an outer solar system moon.'

The theory has let some scientists to imagine a future in which humans could colonise space by sending DNA to distant planets and 'printing' a new civilisation.

In a talk at the Smithsonian Magazine's 'The Future is Here Festival' in Washington DC in May, Nasa engineer Adam Seltzner spoke about the future of space exploration.

And aside from reiterating the importance that we continue manned exploration, he spoke of a lesser-known method of space exploration – sending the human genome to far-flung planets.

The idea was first dreamed up by Harvard biologists Dr Gary Ruvkun and Dr George Church, as reported in a Harvard Medical School release.

How these bacteria would grow into humans is up for debate.

They could simply be left to evolve, as life did on Earth, seeding another planet with our own organisms.

Alternatively, an autonomous machine capable of creating cellular life could be sent thousands of years in advance to a habitable exoplanet outside the solar system.

Upon arrival, information on how to genetically construct a human would be beamed to the machine.

Of course, these proposals are something that will only be possible for humans hundreds, or perhaps thousands, of years in the future.

But many scientists are of the belief that we will one day be able to create multicellular life - and it stands to reason this could include an organism as complex as a human.