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Scientists discover evidence for a habitable region on Saturn’s moon Enceladus

phys.org

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Re: Scientists discover evidence for a habitable region on Saturn’s moon Enceladus

#61

Post by devrandomguy »

dmitrygr wrote: post #30

A lot of articles like this overlook a lot of physics that actually matter a lot. Not only would it be incredibly difficult to get humans up there, much more so than Mars, but even once we get there we have serious problems. Just like Mars, we can solve many problems with electricity. We can create water and many chemicals, provide shelter and even ways to grow food. On Mars you can get electricity vs solar, which is…

One possibility for a useful energy source, in a dirty crowded moon system, would be chemical reactors. Rhea has a thin, oxygen-rich atmosphere, and if you have oxygen, you can burn almost anything. Titan's methane seems like an obvious choice of fuel.

It would be really interesting to compare the economics of shipping large volumes of fuel around moon system, to shipping them around a relatively tiny ocean.

Re: Scientists discover evidence for a habitable region on Saturn’s moon Enceladus

#62

Post by Animats »

scallycat wrote: post #13
Animats wrote: post #6

So there's this big hydrogen vent in a moon of Saturn. Where's the energy coming from to drive that? Too far from the sun. Enceladus is tidally locked to Saturn, so there are no tidal forces. Enceladus has very low orbital eccentricity, a near-circular orbit, so there are very low tidal forces from that. Some phenomenon must provide energy for the hydrogen jet.

Orbital eccentricity gives rise to tidal forces in this case.

What orbital eccentricity? That moon has a nearly circular orbit. Much less orbital eccentricity than Luna.

Re: Scientists discover evidence for a habitable region on Saturn’s moon Enceladus

#63

Post by philipov »

Symmetry wrote: post #33
bluedino wrote: post #29

Even if it was habitable, isn't most of the problem with going to Mars the fact that it takes a half of a year to get there - not a couple days like the moon? Saturn is YEARS away. Like 4-7 depending on where the planets are at.

Yeah, a Hohmann transfer to Saturn would take a very long time. The trip is long enough, though, that it would make a lot of sense to spend months accelerating under an electric drive in order to achieve a faster transfer. But it is 10 km/s even for Hohmann burn and once you get there you need to shed 4 km/s. In theory you could aerocapture but that isn't something we have the technology for right now. Well, we know…

Okay, so it's simple: first we build a base on Titan as the transportation hub for the Saturn system, and transfer there to get to Enceladus [autocorrect wants to change this to Enchiladas].

Wouldn't it make sense to have a methane mining base on Titan anyway?

Re: Scientists discover evidence for a habitable region on Saturn’s moon Enceladus

#64

Post by Kholo »

jerf wrote: post #60
kingkawn wrote: post #54

Earlier quoted context omitted.

You know how sometimes you've got the best possible people, really brilliant, and all the resources, and still things go wrong? Rockets blow up for example. The fear of that happening which you see fit to mock, is justified, and no amount of self-righteous dismissiveness is going to help bridge that difference.

The thing is, even if a rocket blows up and a few dozen pounds of uranium get strewn about, it isn't anywhere near the disaster people think it is. Until we can rationally compute dangers instead of simply assigning infinities to the dangers, we're not going to get anywhere. There is ~4.5 billion tons of uranium already in sea water [1]. If that fact surprises you, you may just have not known it. If that fact scares…

This stuff has been studied for a long time and is still being studied - https://www.nasa.gov/topics/technology/features/ntrees.html

So I don't know what you are raving about.

Re: Scientists discover evidence for a habitable region on Saturn’s moon Enceladus

#65

Post by trose »

bluedino wrote: post #29

Even if it was habitable, isn't most of the problem with going to Mars the fact that it takes a half of a year to get there - not a couple days like the moon? Saturn is YEARS away. Like 4-7 depending on where the planets are at.

The article isn't talking about human habitation. It says that we collected evidence that may suggest that there are hydrothermal vents below the surface which may be able to support microbial life like Earth's hydrothermal vents.

Re: Scientists discover evidence for a habitable region on Saturn’s moon Enceladus

#66

Post by aperrien »

jerf wrote: post #60
kingkawn wrote: post #54

Earlier quoted context omitted.

You know how sometimes you've got the best possible people, really brilliant, and all the resources, and still things go wrong? Rockets blow up for example. The fear of that happening which you see fit to mock, is justified, and no amount of self-righteous dismissiveness is going to help bridge that difference.

The thing is, even if a rocket blows up and a few dozen pounds of uranium get strewn about, it isn't anywhere near the disaster people think it is. Until we can rationally compute dangers instead of simply assigning infinities to the dangers, we're not going to get anywhere. There is ~4.5 billion tons of uranium already in sea water [1]. If that fact surprises you, you may just have not known it. If that fact scares…

I think that what you're describing is some sort of variant of the "Won't somebody please think of the children" rhetorical tool (or the fallacy "Appeal to Emotion"). I don't know what to do about it, but I can recognize it.

Re: Scientists discover evidence for a habitable region on Saturn’s moon Enceladus

#67

Post by AnimalMuppet »

Kholo wrote: post #64
jerf wrote: post #60

Earlier quoted context omitted.

The thing is, even if a rocket blows up and a few dozen pounds of uranium get strewn about, it isn't anywhere near the disaster people think it is. Until we can rationally compute dangers instead of simply assigning infinities to the dangers, we're not going to get anywhere. There is ~4.5 billion tons of uranium already in sea water [1]. If that fact surprises you, you may just have not known it. If that fact scares…

This stuff has been studied for a long time and is still being studied - https://www.nasa.gov/topics/technology/features/ntrees.html So I don't know what you are raving about.

He's talking about public perception, not about NASA research.

Re: Scientists discover evidence for a habitable region on Saturn’s moon Enceladus

#68

Post by AnimalMuppet »

Arizhel wrote: post #50
ekianjo wrote: post #25

Earlier quoted context omitted.

Even better, ban newsweek which is nothing but a tabloid these days.

If you're going to ban anything that's basically a tabloid these days, doesn't that mean there won't be any news sites left?

Reuters is still pretty good.

Re: Scientists discover evidence for a habitable region on Saturn’s moon Enceladus

#69

Post by Symmetry »

philipov wrote: post #63
Symmetry wrote: post #33

Earlier quoted context omitted.

Yeah, a Hohmann transfer to Saturn would take a very long time. The trip is long enough, though, that it would make a lot of sense to spend months accelerating under an electric drive in order to achieve a faster transfer. But it is 10 km/s even for Hohmann burn and once you get there you need to shed 4 km/s. In theory you could aerocapture but that isn't something we have the technology for right now. Well, we know…

Okay, so it's simple: first we build a base on Titan as the transportation hub for the Saturn system, and transfer there to get to Enceladus [autocorrect wants to change this to Enchiladas]. Wouldn't it make sense to have a methane mining base on Titan anyway?

Refueling on Titan might make a lot of sense. Getting methane is pretty much just a matter of piping it or freezing it out of the atmosphere. Getting oxygen from the CO2 in the atmosphere would be an industrial process and require considerable energy but it beats having to carry the oxygen with you.

Re: Scientists discover evidence for a habitable region on Saturn’s moon Enceladus

#70

Post by knz »

Symmetry wrote: post #47
knz wrote: post #43

Earlier quoted context omitted.

> I'm really sort of surprised that nobody is seriously discussing how to build a nuclear reactor in space yet. Isn't the fear that this would start another nuclear arms race? I'm not sure if the threat is that much worse (considering how effective the nuclear triad is) but any perceived advantage would have consequences that increase the threat of nuclear war.

It's nuclear weapons that nobody wants in space, not nuclear reactors. Almost every outer solar system probe has had a nuclear power source that relied on decay and the Russians even put reactors on one series of satellites IIRC. And people are working on building reactors. NASA has plans for one[1] in the 100kWe range. But mostly spacecraft have had low power needs and so people haven't wanted to deal with the compl…

> It's nuclear weapons that nobody wants in space

I should have been more specific - isn't the fear that nuclear power generation in space could be utilized as part of a weapons program.

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