Back in 2015, NASA’s late, great Cassini spacecraft sampled material from one of Enceladus’s icy plumes. Among other interesting components, the orbiter found that the Saturnian moon’s icy spray contained methane. Years later, a new study suggests that methane could be of biological origin, making Enceladus even more enticing for astrobiologists and tinfoil hat-wearers alike.

The paper, published on February 27 in Nature Communications, describes how a team of scientists exposed three kinds of archaeans to various temperatures and pressures similar to the ones found on Enceladus. These particular microbes — which look very much like bacteria under a microscope — are methanogenic, meaning they produce methane as a byproduct of metabolism.

One species of microbe called Methanothermococcus okinawensis survived and even grew substantially in the researchers’ modeled scenarios. Most importantly, it produced methane gas in the high-pressure environments it was exposed to. This makes sense, considering Methanothermococcus okinawensis came from a hydrothermal vent off the island of Okinawa in Japan, and for years, researchers have thought similar hydrothermal vents exist on Enceladus.

“We were able to show that, under putative Enceladus conditions, biological methane production occurs in the lab,” the study’s co-author Simon Rittmann, of the Department of Ecogenomics and Systems Biology at the University of Vienna in Austria, tells in an email. “Hence, some of the methane detected on Enceladus could in principle be of biological origin.”

enceladus cutaway
Saturns icy moon, Enceladus, and its lil' plumes.

We can’t stress enough that this isn’t definitive proof of aliens on Enceladus. While we’d all like to see space tardigrades swimming around on this icy moon, there’s so much more research to be done. Frankly, we’d need another mission to the Saturn system. That could be complicated since NASA doesn’t have any formal plans to send another mission to the gas giant any time soon.

Hopefully, someone pulls through and sends their version of Cassini 2.0. Hey, Elon Musk, do you like Saturn?