On the way up, the frozen droplets reach speeds of up to 1,000 km/h (620 mph). When they strike the walls of the icy cracks, they shatter into fragments just a few micrometers across. Each resulting ice particle therefore often consists of a single, highly concentrated substance that was previously dissolved in the ocean.

"Enceladus actually does a lot of the work for us in preparing samples for analysis that usually take a lot of effort in chemical labs on Earth," Postberg said. "The oceanic constituents are separated from each other and simultaneously concentrated into individual ice particles."

How does this help find life?

The sorting mechanism matters for the hunt for biosignatures — measurable indicators of life, such as remnants of microbial cells. If an ocean droplet contained material from alien microbes, that material could separate out as the droplet froze. After fragmentation, microbial material would likely sit in only a small fraction of the ice particles. In those few particles, though, it would be highly concentrated and relatively pure.

"Future spacecraft will have to analyze many individual ice particles in the plume," Postberg explained. "But if they come across one with microbial material in it, they could identify biosignatures in the particle relatively easily with already available technology."

The finding has implications for planned missions such as ESA's L4 mission, which will specifically search for signs of life on Enceladus. Postberg's lab at Freie Universität Berlin has already shown in laboratory studies that specialized instruments can detect microbial cellular material in individual plume particles.

Could life actually survive there?

The second study, led by scientists at Ludwig-Maximilians-Universität München with contributions from Postberg and his Freie Universität colleague Dr. Nozair Khawaja, tackled that question directly.

The team recreated Enceladus's ocean in the laboratory. The real ocean has very little oxygen, a very high carbonate concentration, and is strongly alkaline, with pH values of 10 or 11. The researchers simulated these conditions, including the ocean's hydrothermal interaction with its rocky floor, and then introduced Methanothermococcus okinawensis — a methane-producing archaean, a type of microbe that lives near deep-sea hydrothermal vents on Earth and needs no oxygen. Its metabolism runs on just hydrogen and carbon dioxide.

The results surprised the team. The organism failed to grow in an optimal lab medium at such high pH, because too little carbon dioxide stayed dissolved. In the Enceladus simulant, by contrast, it kept growing, producing methane from hydrogen generated by water-rock reactions. The microbes even adapted their metabolism to the scarce carbon dioxide.

"This was really a surprise to us," Khawaja said. "This was an experiment for which we did not expect such a successful outcome."

What is the bottom line?

Taken together, the two studies strengthen the case that Enceladus is both potentially habitable and practically searchable. "On Enceladus the specific geochemical conditions might allow one of the oldest known metabolic systems on Earth to work, even in very alkaline environments," Postberg said.

He added a caution: "While that doesn't mean that there is life on Saturn's moon, our first study shows that — in the event that there is — future space missions might have a good chance of finding traces if they analyze individual ice grains from Enceladus's plume."

Both papers appear in Science Advances (2026): Postberg's ice-grain study (DOI: 10.1126/sciadv.aee7256) and the LMU-led methanogenesis study by Vanessa Helmbrecht and colleagues (DOI: 10.1126/sciadv.aei0167).