It wouldn’t be the sort of life science fiction is made of, but it’d be an incredible find nonetheless — this week, NASA announced that one of Saturn’s moons, Enceladus, has the right conditions to allow for life to exist. Unfortunately, we won’t know whether or not it actually does for a long, long time.
The data used to make the discovery came from NASA’s Cassini-Huygens probe, which was launched all the way back in 1997. An encounter with Enceladus in 2005 revealed eruptions from the south pole of the moon ejecting water vapor. After 2015, the probe had some more close encounters with the moon, and those adventures are the subject of a new study published in Science this week. Those trips found that those eruptions were also shooting off salts, silicates, nitrogen, and a ton of hydrogen molecules. It was that last bit that raised eyebrows — the big discovery is that the moon is shooting off so much hydrogen, there must be some reaction going on under the surface that’s actively creating more.
From the outside, life doesn’t look likely on Enceladus. Unsurprisingly for a tiny moon orbiting a planet that is very, very far away from the sun, the moon is covered by a sheet of ice. What’s been discovered is that underneath that ice is a huge, warm, and very active ocean that is likely creating not only molecular hydrogen, but methane — something that microorganisms could feed off of.
The probe didn’t find any proof of those microorganisms — while the environment is right, there’s no guarantee Enceladus is home to a bunch of budding swimmers. Unfortunately, if that discovery is to be made, it won’t be thanks to Cassini-Huygens. After 20 years, the probe is just about out of fuel. In September of this year, the probe will go out with a glorious bang, plowing into Saturn and sending back images of the planet’s atmosphere before it signs off for good and becomes a permanent ball of gravity-crushed scrap somewhere on Saturn’s core.