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Martian life could share Earth DNA – but bugs on Saturn’s moons would be ‘new’

Scientists investigating the possibility of extraterrestrial life have found evidence of a key chemical ingredient spewing from the icy surface of one of Saturn’s frozen moons.

Planetary scientist Chris Impey told the Daily Star that the discovery of even microbial life on one of Saturn's moons would be a massive boost for the theory that life is commonplace in the Universe.

Chris, whose new book Worlds Without End investigates the possibilities of life on other planets, explains that the discovery on life forms on Mars would be less exciting, because we exchange material so often with our near neighbour thanks to meteorites.

READ MORE: Saturn's moon Titan 'could host life' as rivers deeper than first thought, study claims

“Space rocks can travel from Mars to the Earth and, with lower probability, from Earth to Mars,” the Scottish-born astronomer says.

“So Mars life need not be an independent origination, unless the biochemical basis and genetic structure was different.

“For life on Europa or Titan or Enceladus or any outer Solar System location, it would almost certainly be independent origination”.

That would mean that life had started more than once in the Solar System – and logically must exist in many other places in our galaxy.

Making sure that we don’t accidentally find some earthly bugs in our Mars or Enceladus samples is a tricky operation: “Most spacecraft are sterilised before they reach the launch pad and then again as they travel through the Earth's atmosphere,” Chris explains.

“But the decontamination is not perfect, so there is a small chance of contamination. Samples we bring back from Mars will be treated with great care so little chance of contamination."

Unfortunately for sci-fi fans, wherever we find alien life, it will almost certainly be microscopic creatures rather than little green men: “Earth had microbial life for billions of years before life moved onto land and plants and animals developed,” Chris says.

“Logically, you will always get microbes before hi-tech civilisations, so there will be more of the former, perhaps orders of magnitudes more”.

  • Aliens may have law forbidding them from interacting with 'primitive' species like ours

And if we did discover a civilisation much like our own, we wouldn’t necessarily say “help” right away: “We would study it carefully to learn as much as possible without interacting with it or communicating with it, a kind of Cautionary Principle,” Chris explains.

“If it was less advanced than us, we could teach it and help it, if more advanced, it could help us – assuming it was benign."

In the closing chapter of Chris’s book he speculates about a future colony on one of the planets around the Sun’s nearest stellar neighbour, Proxima Centauri.

While some experts, such as NASA Goddard astrophysicist Erika Nesvold, have raised ethical concerns about raising kids on a planet some 25,300,000,000,000 miles from their “birthright” here on Earth, Chris is a lot more relaxed about the ethics of a one-way trip to the stars.

“Adults can choose and sign a waiver," he says, "but yes, their children would have had no choice”.

However, Chris points out: “Children all over the world are born into wildly varying circumstances, with no choice in the matter. They would be unique pioneers, which is worth something!”

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