On Earth, tectonic plates mean large pieces of the planet’s crust are moving and interacting. Meanwhile, inside Europa’s ocean, something weird is going on.
New research suggests that the frozen surface of Jupiter’s moon Europa may also experience tectonic activity. If so, this process could help transport materials — such as nutrients for life — to the liquid water ocean just beneath the moon’s icy crust.
Europa’s crust appears to contain oxidants and other chemical food within it, which can support life. So, if the tectonic plates are moving, then they could cause a process called subduction. This is a process where those materials spread into the sea beneath and provide the material for whatever alien life hides beneath.
“If indeed there’s life in that ocean, subduction offers a way to supply the nutrients it would need,” said Brandon Johnson, an assistant professor in Brown’s Department of Earth, Environmental and Planetary Sciences and a lead author of the study published in the Journal of Geophysical Research: Planets on Monday.
Geophysicists from Brown University in Providence, Rhode Island used a computer simulation to map subduction—where one giant slab of ice forces under another.
The team created a sophisticated computer model of Europa, based on Earth’s tectonic activity. Thus, suggesting that below the very cold surface of the moon, there is a slightly warmer layer of ice.
They have observed evidence on the moon’s surface of rising seawater from below the ice shell. That upwelling water should leave behind a high concentration of salts.
Salt could force slabs of warmer ice all the way down to the moon’s vast underground ocean. It also encourages ice to conduct heat, which is why we salt snowy roads in winter.
“Adding salt to an ice slab would be like adding little weights to it because salt is denser than ice. So rather than temperature, we show that differences in the salt content of the ice could enable subduction to happen on Europa,” Johnson said.
“It’s fascinating to think that we might have plate tectonics somewhere other than Earth,” said Professor Johnson. “Thinking from the standpoint of comparative planetology, if we can now study plate tectonics in this very different place, it might be able to help us understand how plate tectonics got started on the Earth.”
So, the movement of plates could be fundamental to life on Jupiter’s moon Europa. And if you think organisms might be roaming underneath the moon’s vast ocean, scientists would not find it funny.
Thumbnail image: Europa moon. Credit: NASA/JPL-Caltech