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Huge Ocean Confirmed Underneath Solar System's Largest Moon
sciencehabit writes The solar system's largest moon, Ganymede, in orbit around Jupiter, harbors an underground ocean containing more water than all the oceans on Earth, according to new observations by the Hubble Space Telescope. Ganymede now joins Jupiter's Europa and two moons of Saturn, Titan and Enceladus, as moons with subsurface oceans—and good places to look for life. Ceres, the largest object in the asteroid belt, may also have a subsurface ocean. The Hubble study suggests that the ocean can be no deeper than 330 kilometers below the surface.
I should add that we need to think better about how we want to think about early life, what's likely to lead to an evolutionary path.
On one hand, we have self replicators like the misfolded prions of BSE. Injected into a healthy human, a single misfolded prion can begin taking others in the person's body and misfolding them, leading to a catalytic cycle that spreads like a virus and eventually kills the person. One could conveive that if there were a wide range of "roughly prion-like" chemicals in some primordial soup, that their variations in folding could lead to evolutionary adaptation with time.
Is this reproduction some realistic sort of form of protolife? By far most people would say no. Prions are large, complex proteins; the concept of an early world containing large amounts of this exceedingly specific complex protein, or even proteins not exactly the same but still similar enough for reproduction, is exceedingly unlikely.
On the other hand, let's look at something like tin pest. Objects made of pure tin are stable at warmer temperatures, but at low temperatures they can develop something called "tin pest" where tiny spots break out, and then over the course of months expand and eat up the object, breaking it down into dust, like bacterial colonies spreading across a petri dish. This is a low-temperature stable allotrope of tin which catalyzes its own formation to reproduce itself.
Is this reproduction some realistic soft of form of protolife? By far, most people would say no. Contrary to prions, it's input is quite simple: plain, ordinary tin. It's easy to picture where this specific case or other natural cases like it could occur in some early world. But its problem is different: it's too specific. Tin pest seems unlikely to, say, mutate and start catalyzing the production of phospholipids or similar. It's just one self-catalytic reaction, with no real possibility for alterations.
The earliest forms of protolife surely lie somewhere on the spectrum in-between these two endpoints - not with such glaringly simple inputs as tin pest, such that your reaction is too simple to have any chance of it mutating without outright dying off, but not with inputs so complex as prions that you're unlikely to ever find significant quantities in nature. Surely the earliest forms were some sort of middle ground.
But what they were, specifically? This is totally and utterly unknown at this time.
"Are you hungry? I haven't eaten since later this afternoon." -- Primer
Realistically, it's hard to picture any method that would work other than a nuclear reactor melting itself down through the surface. But then you've got the question of how to handle communications back to the top. That's a *lot* of ice to transmit through.
A 330km cable frozen into the ice that reforms above would be very heavy (tens of thousands of tonnes even if very lightweight), complex to feed, and probably have an unacceptable risk of breakage from shifting / settling ice.
I guess if you considered extremely low bandwidth acceptable you could use a neutrino pulse based transmission method straight from the probe.
Perhaps instead of 330km of cable you could drop behind hundreds of RTG-powered SLF radio repeaters (or thousands of ULF repeaters, or tens of thousands of VLF repeaters...). That'd still be of course incredibly heavy (not just for the power and radio equipment, but for the very sizeable antennae), but that'd likely be more workable than a single 330km cable.
I guess the last option that comes to mind would be to use exceedingly low frequency RF to try to go straight through the ice from the probe itself, less than 1Hz. But surely we're talking an antenna spread out over hundreds of square kilometers to be able to do that.
"Are you hungry? I haven't eaten since later this afternoon." -- Primer
The four Galilean moons are interesting from an evolutionary POV.
Io - Molten sulphur on the surface, purple volcanoes all over it.
Europa - Deep water ocean, thin crust, very active plate tectonics.
Ganymede - Europa with a deep dish crust and cooler core.
Callisto - A rock.
So it would seem that gas giants may have their own "goldilocks zone" when they are orbiting in the colder regions of their host system. So the "average" solar system may have 3-4 "habitable zones" rather than just one.
And did you exchange a walk on part in the war for a lead role in a cage? - Pink Floyd.
I would say its EXTREMELY unlikely to support intelligent life and here is why....complex brains require a LOT of energy and if you remove the marine snow (which would be almost impossible because as others pointed out the upper parts of the ocean would be getting high levels of radiation) from the bottom of the ocean? Its extremely energy poor.
Remember for evolution one has to have the energy capable of supporting that new form and we have plenty of evidence in the record of evolutionary "dead ends" because the environment would no longer sustain them, see the dinosaurs. With only a poor energy source its doubtful they would be able to evolve anything more complex than worms but that doesn't mean we shouldn't go explore simply because finding such a creature would answer many questions about how life began here, such as whether DNA is the only way and whether its always going to be right handed.
ACs don't waste your time replying, your posts are never seen by me.