A recent study focusing on Enceladus, one of Saturn’s moons, reveals that the characteristics of extraterrestrial oceans might make it challenging for scientists to find signs of deep-sea life, even when they directly sample these waters.
Searching for life in extraterrestrial oceans might be more complex than scientists had initially assumed, even when we can directly access these alien waters.
This new research, published today (Thursday, February 6, 2025) in Communications Earth and Environment, examines how Enceladus’s ocean generates distinct layers, which significantly slow the movement of materials from the ocean floor to the upper layers.
Essential indicators of life that researchers seek—such as chemical signatures, microbes, and organic materials—might break down or change as they move through these layered ocean sections. By the time these biological markers reach the surface where spacecraft can collect them, they may be unrecognizable, even if life exists in the deep ocean below.
Flynn Ames, the lead author from the University of Reading, stated: “Consider attempting to find life from the depths of Earth’s oceans by only testing surface water. This illustrates the challenge we encounter with Enceladus, compounded by our limited understanding of the ocean’s physics.”
“We’ve discovered that the ocean of Enceladus resembles oil and water in a container, with layers that hinder vertical mixing. These natural barriers could keep particles and chemical markers for signs of life trapped below the surface for hundreds to potentially thousands of years—much longer than the previously assumed timeframe for reaching the ocean’s surface, which was thought to be just a few months.”
“As the quest for life progresses, future missions to space must be particularly cautious when sampling the surface waters of Enceladus.”
Utilizing computer models akin to those used for studying Earth’s oceans, this research holds significant implications for the ongoing search for life both within our solar system and beyond. As scientists continue to uncover more ice-covered ocean worlds around the outer planets and distant stars, similar ocean dynamics may prevent evidence of life and its essential building blocks from being detected from the surface. Even in places like Enceladus, where material from its ocean is expelled into space for collection, the lengthy journey from the ocean’s depths to the surface can potentially obliterate vital evidence.
