Nasa’s hunt for alien life must start HERE: Scientist says DON’T search Europa
NASA’S hunt for alien life should focus on Saturn’s moon of Enceladus, rather than Titan or Jupiter’s Europa, a senior scientist who played a key role for both Voyager missions and the Cassini probe has said.
The space agency is sufficiently convinced it is planning two multi-billion dollar missions to explore the icy planet in the next decade.
And Titan, the largest of Saturn's moons, which has a dense, nitrogen-rich atmosphere, is sometimes said to be analagous to Earth billions of years ago.
But planetary scientist and NASA advisor Carolyn Porco believes another of the gas giant's moons is an even better candidate.
She explained: “I have a bias, and I don’t deny that.
“But it’s not so much an emotional attachment with objects that we study, it’s a point of view based on the evidence. We simply know more about Enceladus.”
Enceladus, a tiny moon measuring just 310 miles (500km) across, also has a sub-surface ocean – and Ms Porco's words were given weight last week after a study published in the scientific journal Nature identified large organic molecules spewing into space from the its interior as evidence that the moon was a suitable environment for life.
Mrs Porco's work on the Cassini mission in 2013 included leading a team which captured the first images of a hydrocarbon lake on Titan.
But they also provided evidence of the plumes of ice jetting out of Enceladus, and for her, this is more compelling still.
In contrast, the last probe to survey Europa, Galileo, did so in the 1990s, with scientists unable to say for sure whether it has similar plumes there, or whether they contain any organic material.
Ms Porco, speaking to the Ars Technica website, said: “Really, the Europa people don’t know that much.
“There is a lot of excitement, but it’s speculation at this point. Of course I’d choose Enceladus.
NASA explains how Saturn's moon Enceladus could harbour LIFE
"We know it’s the best, and it stands the greatest chance of making that next big step.”
Other moons in the solar system are possible candidates for exploration as well, including Jupiter's Ganymede, which is also likely to have water beneath its surface, while the New Horizons probe has provided evidence of similar features on frigid Pluto.
She quipped: “Everybody wants to have a subsurface ocean these days.”
But for Ms Porco, it's the moon she knows best which is most tantalising, especially given that the geysers of ice are comparatively easy to analyse without landing on the surface.