This post has been updated
A lot of space research is driven by the search for alien life. And that search is becoming more serious and sustained than ever before. For that reason, money has flowed steadily into exoplanet research over the last few years. Governments, scientific foundations, and researchers alike can all get behind the idea of finding another habitable word. The recent discovery of water on Mars made the whole venture seem more probable. Still, the greater focus remains outside our solar system, Earth being the only Earth-like planet in our neck of the woods.
But Carolyn Porco thinks we should think about worlds, not planets, and she’s keeping an eye on Enceladus, one of Saturn’s moons. The sixth largest moon orbiting the sixth planet from the sun is truly a world like no other in the solar system, with 101 geysers of icy particles and organics-laced vapor erupting from its south polar province accompanied by surprising amounts of heat. Europa, a moon of Jupiter about the size of our moon, hogs most of the spotlight, but Porco, a planetary scientist and one of the world’s premier experts on all things Saturnine, says astrobiologists in particular need to give the cryovolcano geyser-studded orb another look .
“We need to pay attention to Enceladus,” she says. She’s not above being direct.
This week, Porco traveled to Washington D.C. to make her case at Space Science Week, an event hosted by the National Academies of Sciences, Engineering, and Medicine. She argued that humanity needs to send a spacecraft to Enceladus. That means asking for money and that means building consensus. She’s ready to do both.
Why is Enceladus so compelling? Upon first glance, the moon looks like a total ice world. After all, most of the planet’s surface is covered in a fresh, clean layer of ice that bounces back any sunlight that hits the surface. At high noon, the planet’s temperatures only rise up to minus 324.4 degrees Fahrenheit.
But there’s more to it than meets the eye. Porco tells Inverse that the moon’s subsurface ocean meets the basic criteria for an extraterrestrial study of the water. It’s salty, but an extremophile that has evolved to handle such high pH levels might be able to survive. And there’s evidence of such hydrothermal activity on Enceladus.
In fact, the hydrothermal activity raises what is probably the coolest part about Enceladus — the geysers. Massive plumes of water vapor shoot out these babies along with trace amounts of simple hydrocarbons like methane and propane. These carbon bearing molecules are proof of some kind of hot reactive activity happening underground — which could be enough to keep any simple organisms warm and (relatively) cozy.
Altogether, the data is there to help support the notion that primitive water-based life just might be right there on Enceladus. In the words of Porco, “it’s tantalizing. Enceladus is the most promising target for any investigation related to astrobiology.”
She goes on to point out that “we just need to fly there and collect samples. All we have to do is build something that will go there and pick some stuff up.” The closest thing NASA ever came to fulfilling something like this was the Enceladus Life Finder Discovery proposal to send a probe to fly though Enceladus’ plume multiple times and* assess the potential for habitability in the internal ocean of the moon. Unfortunately, mission was not selected.
Now, NASA has made it possible for teams to propose to revisit Enceladus in the New Frontiers program, which would support missions of much larger scope than the Discovery program.
Porto hopes hers and others’ efforts to bring greater awareness to Enceladus will spur NASA or another agency to finally make real plans to send something to the moon. Perhaps we might soon find out E.T. lives much closer than we think.