Why Jovian moon Europa's shell rotates differently than its interior
What's the story
A new study offers insights into why Jupiter's moon Europa rotates at a different rate than its interior.
While there is strong evidence suggesting that Europa houses a vast internal ocean beneath its icy outer shell, the new computer-modeling-based research is the first to depict that Europa's ocean currents could be contributing to the rotation of its icy shell.
Context
Why does this story matter?
The fact that Europa could be home to vast oceans has made it an interesting target in the hunt for life beyond our home planet.
It is predicted that even a passing spacecraft should be able to image Europa's enormous oceans, without actually landing on its surface.
It is also suggested that Europa's oceans may contain more water than the combination of Earth's oceans.
Study
What is the significance of the new study?
For a long time, scientists have known that Europa's shell could be disengaged and freely floating, rotating at a different rate than the ocean below and its rocky interior.
In light of the recent study, researchers suggest that water may be pushing against the icy shell, which in turn could possibly be accelerating and slowing down the rotation of the moon's icy shell.
Information
"Heating and cooling of Europa's ocean may drive currents"
"It was known through laboratory experiments and modeling that heating and cooling of Europa's ocean may drive currents," said Hamish Hay, the study's author. "Now our results highlight a coupling between the ocean and the rotation of the icy shell that was never previously considered."
Details
A key aspect of the study involved estimating drag forces
An important part of the study involved estimating drag forces, which is the horizontal force that Europa's ocean exerts on the icy shell above it.
The investigation also hints at how the power of ocean currents on Europa and its drag against the ice layer could shed light on the geological features that are observed on the moon's surface.
Geology
NASA's upcoming Europa Clipper mission could provide important insights
It might even be possible to precisely determine how fast the icy shell rotates, based on the data that will be obtained from NASA's upcoming Europa Clipper mission.
By comparing images snapped by Europa Clipper with existing photos from NASA's Galileo and Voyager missions, scientists could examine the features of Europa's surface and evaluate if the moon's icy shell has changed position over time.
Detail
What is the Europa Clipper mission about?
The Europa Clipper mission is currently under development and is set to launch in 2024.
The spacecraft will begin orbiting Jupiter in 2030 and its main science goal is to determine whether Europa could support life.
Its other objectives include probing the nature of the moon's icy shell and the subsurface oceans, along with their composition and geology.