Finding the Limits of Ocean Worlds

Lab experiments with saltwater solutions have provided researchers with a range of temperatures where water remains liquid under icy world conditions.

IMAGE: This image, taken by the Galileo spacecraft in 1996, shows two views of Jupiter’s ice-covered satellite, Europa. The left image shows the approximate natural color while the right is colored to accentuate features. Europa is about 3,160 kilometers (1,950 miles) in diameter, or about the size of Earth’s moon. CREDIT: NASA Jet Propulsion Laboratory

We’ve written before about icy worlds in our solar system and how they have liquid water under those icy shells. These worlds include the likes of Europa, Ganymede, Titan, and Enceladus, and it turns out that they make Earth look dry.

Now, in a new paper published in the journal Cell Reports Physical Sciences, a team of researchers has provided possible temperature ranges for keeping all that water in its liquid form. That’s sort of key for developing life beneath the surface, after all. Co-author Baptiste Journaux explains: The more a liquid is stable, the more promising it is for habitability. Our results show that the cold, salty, high-pressure liquids found in the deep ocean of other planets’ moons can remain liquid to a much cooler temperature than they would at lower pressures. This extends the range of possible habitats on icy moons and will allow us to pinpoint where we should look for biosignatures or signs of life.

The team ran experiments to find just where the lowest temperature of various saltwater solutions was where the solution was still liquid. Saltwater can stay liquid…