Uncovering the Secrets of Europa: How Ocean Currents Could be Affecting the Rotation of its Icy Shell
Scientists have long suspected that the icy shell of Jupiter's moon Europa rotates at a different rate than its interior.[0] Now, a new study has provided a possible explanation for this phenomenon. Researchers used computer models to suggest that Europa's ocean currents could be contributing to the rotation of its icy shell.
Hamish Hay, the study’s author and a researcher at the University of Oxford, said, “Before this, it was known through laboratory experiments and modeling that heating and cooling of Europa’s ocean may drive currents. Now our results highlight a coupling between the ocean and the rotation of the icy shell that was never previously considered.”
The team used a NASA supercomputer to model Europa’s ocean and investigate how heating and cooling affect the water’s circulation.[1] They found that the shell may develop ridges and cracks due to the ocean’s currents pushing and pulling on it over time.[1] Additionally, the researchers calculated drag forces, which is the horizontal force that Europa's ocean exerts on the icy shell above it.[0]
The upcoming Europa Clipper mission will determine how fast the icy shell rotates.[1] Scientists will be able to compare images taken by the Europa Clipper with those taken by NASA's Galileo and Voyager missions in order to evaluate the locations of ice surface features and potentially determine if the position of the moon’s icy shell has changed over time.[1]
Co-author and Europa Clipper Project Scientist Robert Pappalardo of JPL said, “To me, it was completely unexpected that what happens in the ocean’s circulation could be enough to affect the icy shell. That was a huge surprise. And the idea that the cracks and ridges we see on Europa’s surface could be tied to the circulation of the ocean below – geologists don’t usually think, ‘Maybe it’s the ocean doing that.’”[1]
At the start, the circulation was vertical, however, the rotation of the moon as a whole caused the water to shift to more of a horizontal flow.[1] The ocean's circulation patterns may change over time due to a change in the degree of inner warmth, which could result in the shifting of the frozen shell above at a faster or slower rate.[1]
According to Hamish Hay, this research could be important in understanding how other ocean worlds’ rotation speeds may have changed over time.[1]
0. “Why Jovian moon Europa's shell rotates differently than its interior” NewsBytes, 14 Mar. 2023, https://www.newsbytesapp.com/news/science/study-reveals-oceanic-currents-may-affect-rotation-of-europa-s-shell/story
1. “The rotation of Europa’s icy crust may be affected by ocean currents” Tech Explorist, 14 Mar. 2023, https://www.techexplorist.com/rotation-europa-icy-crust-affected-ocean-currents/57589/
