Scientists Just Solved a Cosmic Mystery About Hidden Oceans Under Ice Moons
Imagine swimming in an ocean you've never seen, buried miles beneath a shell of ice, on a moon orbiting a planet millions of miles away. Wild, right? This isn't science fiction—it's real life on moons like Europa (around Jupiter) and Enceladus (around Saturn).
For years, scientists have used powerful computers to simulate how water moves in these hidden oceans. But here's the puzzle: their simulations kept disagreeing. Some said water might zip along at faster than a walking human can run. Others suggested water barely trickles slower than a garden snail. That's like predicting a car will drive either 5 mph or 60 mph from the same science experiment!
A new study, published by researchers including Manuel Jansen, has finally cracked this cosmic case.
Manuel
Jansen
We show that heating from the solid core balanced by heat loss through the ice sheet can drive an ocean circulation, but the resulting flows would be relatively weak and strongly affected by rotation.
The Detective Work
The scientists didn't run new computer models. Instead, they went back to basic physics—like checking the engine of a car instead of guessing from the outside. They asked: how much energy actually flows into these oceans?
The Energy Input
They found that on Europa, heat from the rocky seafloor pumps out a tiny 0.02–0.1 W/m²—barely a whisper of warmth. Enceladus gets even less, just 0.01–0.08 W/m². That's thousands of times weaker than heat from sunlight hitting Earth's oceans.
The Translation
Yes, there's enough energy to make water move—but only very, very slowly.
The Mind-Blowing Answer
The data shows these hidden oceans flow at roughly 0.01–0.05 meters per second—that's less than 2 inches every second. So instead of rushing rivers, picture thick, slow-motion conveyor belts of water, crawling along over hours and days.
But here's the really strange part: rotation completely takes over the flow.
Europa's Spin Effect
On Europa, the "critical rotation length"—the distance before spin really kicks in—is just 8–30 meters, while the ocean is 50–150 kilometers deep.
Enceladus' Spin Effect
On Enceladus, it's less than 1 meter!
The Analogy
That's like if Earth's entire ocean suddenly started spinning like a giant record player after just a few giant steps.
Key Takeaway: Beneath the frozen surfaces of distant worlds, oceans are quietly humming along—sluggish, mysterious, and waiting for us to learn their secrets.
Why Should You Care?
These oceans might be the best places to look for alien life in our solar system. If tiny microbes exist there, understanding how water moves helps us guess where nutrients and energy might flow. It also tells us whether ice geysers on Enceladus—already spotted shooting into space—can be powered by these gentle ocean currents.
The Catch
The researchers admit they don't know everything yet. They assumed the oceans are in steady "balance" like a calm lake. Real moons might have ice sheets growing or shrinking, which could change everything. And on Europa, magnetic forces from Jupiter might also push water around in ways they haven't figured out.
Reference: Jansen, M. F., Kang, W., Kite, E., & Zeng, Y. (2023). Energetic constraints on ocean circulations of icy ocean worlds. arXiv:2206.00732v2 [astro-ph.EP]