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New Evidence Points To Icy Plate Tectonics On Europa (gizmodo.com)
According to new research published today in Journal of Geophysical Research: Planets, Europa has what it takes to support plate tectonics. "Using computer models, a team lead by Brown University planetary scientist Brandon Johnson was able to demonstrate the physical feasibility of icy plates driving deep into the icy interior in a processes similar to what's seen on Earth," reports Gizmodo. "Excitingly, this same process could be delivering important minerals to the ocean below, heightening the moon's status a potentially habitable world." From the report: Europa has surface features reminiscent of Earth's mid-ocean ridges. For astronomers, this hinted at geological processes akin to subduction zones, where, on Earth, tectonic plates slide underneath another, sinking deep into the planet's interior. Several years ago, researchers Simon Kattenhorn and Louise Prockter posited this explanation when they noticed that a 20,000 square-kilometer (7,722 square-mile) chunk of ice had mysteriously disappeared from Europa's surface. Their explanation was that Europa's surface, like a gigantic jigsaw puzzle, is composed of tectonic plates, and that occasionally a plate of ice will sink beneath the other into warmer layers below. But this observational evidence of extension and spreading needed to be supported by geophysical reality. To that end, Johnson's team ran a computer simulation to see if it was possible for ice to sink in this way.
On our planet, subduction is primarily driven by differences in temperature between a descending slab and the surrounding mantle. Dense crustal material features a negative buoyancy that drives it down into the mantle. The Brown University scientists figured a similar thing happens on Europa, but with ice. In the case of Europa, the researchers surmised that the moon has two frozen layers -- an outer lid of very cold ice that sits above a layer of slightly warmer convecting ice. Their models showed that subduction is indeed possible in this alien environment, but only if the outer shell contains varying amounts of salt. This added ingredient provides the necessary density differences for a slab to conduct.
On our planet, subduction is primarily driven by differences in temperature between a descending slab and the surrounding mantle. Dense crustal material features a negative buoyancy that drives it down into the mantle. The Brown University scientists figured a similar thing happens on Europa, but with ice. In the case of Europa, the researchers surmised that the moon has two frozen layers -- an outer lid of very cold ice that sits above a layer of slightly warmer convecting ice. Their models showed that subduction is indeed possible in this alien environment, but only if the outer shell contains varying amounts of salt. This added ingredient provides the necessary density differences for a slab to conduct.
Well, then, since you feel qualified to weigh in on the amount of rocky mass recycled from the icy crust, off the top of your head you should be able to tell us the mass flux from impactors and space dust at Europa. What is it?
Because I guarantee you, people who study these things don't need to google it.
Pinkypants -- my favorite!
I always anticipated this. Tidal forces affect liquids far more than rock or hot pressurized rock (mantle). I mean IO doesn't have anywhere near the amount of water that Europa does and it's being torn and scewed by these immense forces.
I don't see how this makes it more habitable however as large glacial tectonic forces, while similar is appearance to regulr tectonics don't seem to make life any easier on the surface. If anything it makes it more difficult to establish any kind of surface base given how quickly the ice can shift compared to normal mantle based tectonics.
I don't read AC
The earliest claimed fossilized lifeforms on earth are as old as old as 4.28 billion years old. it suggests an almost instantaneous emergence of life after oceans formed 4.4 billion years ago. Obviously Europa doesn't have the same conditions as early earth but perhaps the Abiogenesis is simply slower instead of impossible under those conditions and Europa has had plenty of time. We just don't know