Chris McKay has fallen out of love with Mars. The red, dusty, corroded world no longer holds the allure it once did.
“I was obsessed with life on Mars for many years,” confesses the Nasa planetary scientist, who has spent most of his career searching for signs of life on the red planet.
“It’s seduction at the highest level,” he says. “I’m abandoning my first love and going after this other one that’s shown me what I wanted to see.”
The new object of McKay’s affections is Enceladus, the ice-encrusted moon of Saturn. Investigated by the joint Nasa and European Space Agency (Esa) Cassini space probe, the moon is spewing out plumes of water from its south pole – most likely from a liquid ocean several kilometres beneath the surface. Cassini has found this water contains all the vital ingredients for life as we know it: carbon, nitrogen and a readily available source of energy in the form of hydrogen.
“I think this is it,” says McKay. “From an astrobiology point of view, this is the most interesting story.”
But Cassini only has a few weeks left before it plunges to its death in Saturn’s atmosphere. “We should be flying through that plume searching for life,” he says. “We have developed a new mission to do that, a mission that will fly low and slow through the plume, collect a huge sample and search for evidence of life.”
This proposed mission is currently in competition for Nasa funds with five other future missions – to comets, asteroids and planets. “Right now we have an opportunity to compete,” says McKay. “But I think we’ve got a damned good story: we’re going to find life, what are you going to find? I’m optimistic that we’ll win the competition because it’s such a compelling target.”
As far back as the 1960s, astronomers theorised that the moon might harbour life
Enceladus, however, is just one of several ice-covered worlds in the Solar System with liquid water – and possibly…