Colonization of Gas Giants

umm ... a "giant" planet (like Jupiter, for instance) might have gravity that would be very unhealthy for humans. If you were really high above the surface, the gravity might not be a problem, but then you might not have a lot of atmosphere either.

I mean, I'm not an expert, but you only have to go a few miles above Earth's surface before the atmosphere fades to nothing, and there's no noticeable difference in gravity until you get all the way up into space, which is a lot higher.

On the other hand, Jupiter is 300 times the size of Earth, and yet the gravity on Jupiter is only about 2.5 times Earth's gravity. I think that's because Jupiter is "fluffy." It's really big and therefore when you're on the surface, you're a long way from the center of mass.

Anyways, this sounds like a fun idea!

Not to be a spoilsport, but is it even physically possible for a gas giant to have an earth-like atmosphere?

The gas itself could be a nitrogen-oxygen mixture, but the history behind it would be different. If it weren't for plant plankton, algae, plants, and photosynthetic bacteria, the surface of our planet would have no breathable oxygen. Maybe there could be floating colonies of algae or bacteria to make the oxygen in this planet's atmosphere.

The weather might be something else also. Imagine living in the area and having a storm like the Great Red Spot come through.

You would also have to figure out the nitrogen cycle, the carbon dioxide cycle, and the water cycle. Scientists looking for exoplanets want to find one with liquid water at the surface because life on earth evolved first in the oceans. If your destination has no liquid water, you'd have to come up with a different way for life to evolve there.

Um, gas giants don't have a surface whatsoever. They're basically a huge ball of clouds. I've never even heard of one, even in sci-fi stories having a surface, just having structure/stations where people live orbiting them. That's why the Big Red Spot is centuries old on Jupiter as there is nothing to stop it. Gravity on them would be a killer too. If I remember right, it's created by the size and spin of the planet and gas giants have a gravity, if they had a surface, that would make it nearly impossible to stand upright or move.

Holli

I agree with the others, for the most part a gas giant is not hospitable to human life.
The liquid Hydrogen surface is at extremely high pressure far above the metallic hydrogen and rocky core below.

If the gas giant is near enough to the sun, the moons about the gas giant would be hospitable, though they probably would be:
1) locked with one face to the giant,
2) In harmonic orbits, (The inner moon goes around 4 times, while the next goes twice, the next goes once... factor of 2 for each major moon)
3) Have tides in their crusts (yes, tides in solid rock, worse at the inner-most moon)

Other than that, eveything about non-major moons is random, including retro-grade orbits making them nearly un-reachable.
Most everything else is fair game for your story.

[Edit:]
Now about the colonization, go with mining/manufacturing business model. Embed the start of the base into the ground, and start digging. If you're on an Ice world, like Europa, melt a dozen feet into the ice, and purify water as your export product. Everybody in space needs water. Set up some kind of launch base as soon as possible for export in either case.

Remember, Jupiter has a nasty radiation belt that encapsulates all but the outer-most moon, Callisto. To keep yourself from being deep fat fried, bury yourself ASAP on the inner moons.

I hope that helps,
HSF

Well, they might have a surface. I doubt we can know 100% for sure since we haven't actually landed here

Just as a reference. I think there are a couple of books by Niven & Pournell set in something kind of like what you are after. I've only read the second book in the series btw.

So the premise is THERE IS NO PLANET AT ALL!

The characters live inside a giant ring of gas that orbits a star.

The novel I read was called "Smoke Ring" Since that's all it was, just a giant amalgam of gas at the 'habitable' zone in a star system. Hence everything living inside the area lived in 'Free fall' or micro gravity (Zero-Gee).

Again, I'm not sure how the authors dealt worth the systems local Star's radiation and such. Nor whether they detail things like shepherd moons orbiting about to keep the great gas ring in place.

So, to live in a habitable zone 'in' a gas giant, you might need a reason for that altitude to be habitable as well as a way for the inhabitants, assuming their not native, to exist in a realm that's mainly gas and 'Lighter than air' sort of structures. I know of a couple of Sci-Fi genre games that had had space ships crash into the giant 'gas bag' type creatures that might possibly exist in the ream. Think of something like a living Zeppelin or dirigible.

Hope those pointers help.

Okay, again: we are obviously not talking about a traditional gas giant.

To be a gas giant, it must be (1) "fluffy" (i.e. no solid surface) and (2) very, very large. Neither of these is contradicted in the premise.

To be considered "colonizable", it must have an earthlike atmosphere and RTP. Given what we know about gas giant formation, the first of these is going to require an ecosystem of some sort; oxygen is highly reactive, and if it weren't for plants it would all go away very, very quickly. This isn't that far-fetched. Okay, maybe a little, but it's a staple of SF in the tradition of Arthur C Clarke, so you should be able to get away with it. I mean, you need diatoms and that's about it.

The second isn't that tricky either, since there's going to be some point between bone-crushing and quantum vacuum that's right. As long as the plot doesn't depend on that level being very deep, you should be fine.

The big problem is the gravity. As mentioned before, gravity on Jupiter is about 2.5 times that of Earth, and most of the extrasolar gas giants we know of are much bigger than it, but it has a lot to do with composition. Both Saturn and Neptune have a gravitation strength only slightly higher than Earth (http://en.wikipedia.org/wiki/Earth's_gravity#Comparative_gravities_of_the_Earth.2C_Sun.2C_Moon_and_planets) - Saturn has 1.14 g and Neptune has 1.15, and you can guess how big those are compared to Earth and each other. There is a little problem here - an oxygen-nitrogen atmosphere is considerably more massive than the mostly-hydrogen composition of both Saturn and Neptune, so the breathable stuff will tend to sink to the core, where there's a higher pressure and stronger gravity. But, again, it's produced by an ecosystem. There must be some reason your plant life has to survive on the edge of space (quite possible, as too much depth will occlude sunlight, apply handwaving to taste), so your colonists will be breathing the oxygen as it diffuses towards the core.

As for colonizing... well, there's a very cool system that I think Niven came up with that uses the hydrogen and helium in the gas giant's atmosphere to fuel fusion engines that hold the station aloft. (The original idea was to use it to fire in both up and down at once, so you could move the planet around, hence the name "Candle" - you'd be burning it at both ends. But it should work fine just for holding up a flat dirt-covered surface, as well. Incidentally, anything that's a gas at RTP can theoretically be used to create power by nuclear fusion, so very little handwaving required there.)

Hope that helps.

Dataphile

Would colonizing the moons of a gas giant suffice for your purposes? Or must the colony be "on" the planet itself in some sense?

Dale

So the nano I'm planning possibly went out the door if I can't figure something out.

If a gas planet was NOT as big as Jupiter and the inhabitants were NOT human, meaning didn't have to breath oxygen, would colonization be possible? I don't think colonization is the right word. Maybe... evolution? If there is no water and no land, is it possible to have life forms, like animals and "human"-like things?

My brain is spinning trying to understand all of this. So far I understand that the gas planets have radiation, different atmospheres, and different gravity. What factors could be altered (using my all powerful imagination) to suit a world where beings and animals all lived in the air??? (Not like they all float around, I mean like on ships and the like...)

Thanks a bunch. And so my brain doesn't hurt too much when you all try to help, please make it easier to understand. I'm smart but this late and my brain starts to power down.

There are a few problems to overcome before you can have a gas giant with an Earth-like atmosphere. First of all, Earth's atmosphere is dominated by nitrogen because it's a small planet near the Sun (relative to the Jovian planets, anyway) so most of the hydrogen and helium was driven off by the solar wind eons ago. Any gas giant would have much higher gravity, so it's harder for the light gases to reach escape velocity. Maybe the solar wind in this system is particularly intense, but that also makes the radiation hazard much worse for the colonists. The other problem is that the oxygen in Earth's atmosphere is a byproduct of photosynthesis. Were it not for cyanobacteria, the atmospheric oxygen would probably still be locked up in the form of carbon dioxide and water vapor.

I'm an earth science major, so there ends my expertise. But I've been wondering how feasible it might be to have a balloon-type colony -- if you were to fill a large contained space with breathing air and the rest of the colony wasn't too heavy, shouldn't it float at the depth in the gas giant's atmosphere that matches its density? The thick atmosphere above it would afford some protection from the solar radiation and cosmic rays, and it wouldn't take any energy to hold it at its altitude.

So...

Jovian planet's tend to form closer to their star, so our set up is rather rare in the galaxy. Also, helium and hydrogen were stripped away because they were the lightest of all other gasses, and like in all fluid suspensions the lighter molecules float to the top where they are susceptable to the solar wind.

Also, every heard of something called a gravity curve? Obviously I'm not going to colonize the surface, but more so a level in the atmosphere with a pressure of 1 atm. Also the gravity would increase the closer you get to the surface, so I think it would be alright to say their could be a level like that somewhere.

As for evolution in such an enviroment, bacteria could begin in water droplets in the atmosphere, and then, because life can evolve in a high pressure enviroment, life could be more complex in a hyper pressurized watery ocean on the surface, then flying creatures, or gaseous jellyfish form. These gigantic colonies of jellyfish could be home for more complex quick flying creatures, or animals could evolve like a gaseous ocean inwhich the "birds" behave more like fish.

In Space Battleship Yamato they put a floating island with plants and animals on it. But then again that show doesn't give a damn about explaining things and just goes with what is dramatic.