[Sixstrings]

Just some cool news, another moon in the solar system probably has a water ocean. I'd never even heard of Mimas before:

‘Death Star moon’ could be hiding underground ocean, NASA says

A new study examining Saturn’s moon, Mimas, otherwise known as the ‘Death Star moon’ for its similarity to the Star Wars ship, has found it could possibly be hiding an underground ocean.

The findings, made by a team from US space agency NASA, the European Space Agency (ESA) and the Italian Space Agency (ISA), have been published in the journal Science.

The researchers who have been examining Mimas, one of Saturn’s many moons, found Mimas is by no means a stable planet and has shown itself to be wobbling.

From their understanding, this could only be caused by either its core being in the shape of an American football, or that Mimas actually hides a vast ocean beneath its icy surface.

Previous understanding of the 4bn-year-old moon has been that its heavily cratered surface suggested there was nothing particularly unusual about the satellite compared with other dead moons.

Either way, both possibilities have excited the research team. The latter possibility, in particular, would mean Mimas becomes one of the few known planetary bodies in our solar system to inhabit an ocean, the others being two of its fellow moons, Titan and Enceladus, as well as seven of Jupiter’s moons.

From their own research models, the team led by Radwan Tajeddine from Cornell University in New York, has estimated that if there is an ocean beneath Mimas’ surface, it would be about 24km-31km below, but the researchers have yet to determine what would keep an ocean formed on such a small moon.
http://www.siliconrepublic.com/innovation/item/38821-death-star-moon-could-be

The mystery about this one is how an ocean could have got on such a small moon.

Anyhow -- we need a lot more funding for NASA, we need to get probes that can melt through the ice and send a little sub down into the ocean, on those moons, see what's there.

[Subjectivist]

What kind of 'ocean' at -290?

That is surface temperature exposed to vacuum. Deep in the interior you have both pressure and tidal flexing as the moon orbits Saturn providing heat and compression for liquification. Same thing causes sulfur on Io to erupt in volcanos and water to erupt on Europa.

[Sixstrings]

What kind of 'ocean' at -290?

That is surface temperature exposed to vacuum. Deep in the interior you have both pressure and tidal flexing as the moon orbits Saturn providing heat and compression for liquification. Same thing causes sulfur on Io to erupt in volcanos and water to erupt on Europa.

In case you didn't understand that pstarr, in other words, it's like the tide here on Earth and how our moon pulls the water up with its gravity, then down again, high tides and low tides -- that's from our smaller moon, now imagine the effect of a large planet on a small body that has water.

With saturn and jupiter, their much larger immense gravity affects the oceans on their moons, pulling it back and forth tides so that's what stops it from freezing -- it's as good as geothermal activity with a core, and these moons may well have life in the oceans. We know on earth at least, where there is water and energy then there's life.

Pretty darn cool eh?'

Also about Mimas:

* it's the smallest body in the solar system that is round from the force of its own gravity (does that make it the smallest moon there is then, I think?).

Mimas' diameter is 247 miles, that's pretty small, compare that to diameter of the moon which is about 2,000 miles. The gravity on Mimas must be very low -- around ten times lower than the moon -- that would make landing and operations easier and less fuel intensive.

A great place for a base. Low gravity, a bunch of water, pretty view. Could watch the saturnrise with your morning coffee.

* the water would be under 24 km of ice. I wonder if a probe could ever melt that far down / how that compares to the other moons with oceans (8 total now) / which would be best or moost interesting to ever send a probe sub to

And you know, we all like to speculate on light speed travel one day in the future and maybe humanity getting tot he nearest starts and planets, but we could start with Jupiter and Saturn right here in our solar system.

It would be good practice. Those are far trips out there but not at all impossible like the nearest stars are. Would take two years to get to Saturn.

There's really nothing stopping humanity from doing these cool things.

You don't even need one big rocket like with the moon missions -- you just assemble a modular craft in orbit with however many rocket launches it takes. Pack enough food and water and fuel and off ya go.

[Subjectivist]

Mimas:

* it's the smallest body in the solar system that is round from the force of its own gravity (does that make it the smallest moon there is then, I think?).

Not even close, there are about a hundred small irregularly shaped moons around the four giant planets and even Mars has two, Phobos and Deimos, both are small one shaped like a baked potato and one shaped like a half melted Egyptian pyramid.

[Sixstrings]

Mimas:

* it's the smallest body in the solar system that is round from the force of its own gravity (does that make it the smallest moon there is then, I think?).

Not even close, there are about a hundred small irregularly shaped moons around the four giant planets and even Mars has two, Phobos and Deimos, both are small one shaped like a baked potato and one shaped like a half melted Egyptian pyramid.

It's the smallest that's *round from the force of its own gravity*, though.

That's why planets and and (larger) moons are round. It's their own gravity that causes that sphere shape, strong enough pull and pressure naturally takes a sphere shape.

Anyhow, isn't it all so fascinating?

People just don't realize how diverse our own solar system is, and how much is out there.

Here's something I wonder, about those smaller bodies and asteroids -- how much gravity do they have? I wonder about what size is the breaking point where you wouldn't freefall at all anymore, noticeably, and it would start taking days to get pulled in.

As far as space bases go -- other than the fact those moons are so far away -- I think they'd make great bases since stuff will stick, just enough gravity, but yet so little gravity the fuel cost to land get back into orbit would be negligible.

Of course on some of these smaller bodies if you were to jump you could fly yourself out straight into orbit or escape delta v / even on Mimas you wouldn't want to trhow a hammer or something cuz it's gonna keep going a long ways. Probably whatever gravity level is about like being under water, would be a nice working balance between g and zero go.