Jovian planet with breathable oxygen atmosphere.

[FtlIsAwesome]

Could it be possible for a jovian planet to have an oxygen atmosphere breathable by humans?
Let's say that the humans live in blimp-like stations, and the jovian planet is small like Neptune to reduce the high gravity.

 

[tiny-tim]

Hi FtlIsAwesome!

But where would the oxygen come from?

And wouldn't it immediately react with everything in sight?

 

[Vanadium 50]

Remember, even Earth's original atmosphere wasn't breathable. We're all breathing plant poop. No plants, no O2.

 

[phyzguy]

I think it might be possible. Imagine a Neptune-like planet where Earth is. Cyanobacteria could evolve floating in the atmosphere like they originally evolved in Earth's oceans. Then they would generate the oxygen by photosynthesis. The big question is what about all of the free hydrogen, which a Neptune-like planet would retain, but which Earth is too small to hold.

 

[FtlIsAwesome]

The big question is what about all of the free hydrogen, which a Neptune-like planet would retain, but which Earth is too small to hold.

Hmm. Maybe the hydrogen stays in the upper atmosphere??
Or we could have a smaller-than-Neptune jovian planet that doesn't retain the hydrogen.

Alternatively I abandon the natural breathable atmosphere idea and the jovian's air is terraformed.

 

[phyzguy]

If it's a smaller-than-Neptune planet that doesn't retain hydrogen, then it becomes a rocky planet like the Earth. I wouldn't call it "Jovian" any more.

 

[Ophiolite]

Just hope the magnetic field that seems to be a feature of Jovian planets is absent for some reason. Otherwise no serious biological molecule will remain intact for long.

 

[Nicodemus]

You're never going to have a Jovian planet that produces a breathable atmosphere for humans... not with that gravity, and not to mention that "breathability" isn't really the biggest anti-life factor on your average gas giant. Storms larger than our planet, and only a very narrow band where we could even experience proper gas-exchange in our lungs and blood really preclude breathing.

In a very real sense, the last thing you'd worry about on a Jovian planet is the quality of the atmosphere!

 

[FtlIsAwesome]

If it's a smaller-than-Neptune planet that doesn't retain hydrogen, then it becomes a rocky planet like the Earth. I wouldn't call it "Jovian" any more.

I don't think it would be necessary for a planet to need hydrogen to have a thick atmosphere composed of other gases, and therefore be classified as a Jovian, or mini-Jovian.

Just hope the magnetic field that seems to be a feature of Jovian planets is absent for some reason. Otherwise no serious biological molecule will remain intact for long.

This should solve the problem - From Wikipedia:

Jupiter's broad magnetic field is 14 times as strong as the Earth's, ranging from 4.2 gauss (0.42 mT) at the equator to 10–14 gauss (1.0–1.4 mT) at the poles...

Saturn has an intrinsic magnetic field that has a simple, symmetric shape—a magnetic dipole. Its strength at the equator—0.2 gauss (20 µT)—is approximately one twentieth than that of the field around Jupiter and slightly weaker than Earth's magnetic field. As a result Saturn's magnetosphere is much smaller than Jupiter's...

Exojovians could have varying magnetic field strengths. Let's assume the planet in question has a magnetic field similar to Earth's.
By the way, how exactly do strong magnetic fields adversely affect living organisms?

You're never going to have a Jovian planet that produces a breathable atmosphere for humans... not with that gravity, and not to mention that "breathability" isn't really the biggest anti-life factor on your average gas giant. Storms larger than our planet, and only a very narrow band where we could even experience proper gas-exchange in our lungs and blood really preclude breathing.

In a very real sense, the last thing you'd worry about on a Jovian planet is the quality of the atmosphere!

So what you're saying is:
The high gravity will make it unlivable.
The storms would cause problems.
The band of breathable altitude is narrow.

I will probably use this idea for the story I'm working on, and I already have artificial gravity in it, so this can be the solution for many high-gravity worlds. In most scifi I've only seen artificial gravity used for ships, I've always wondered why they never use it on the surface of a planet.
The storms may be a problem, but some jovians may have less powerful storms. Jupiter has strong lightning strikes, but could other jovians have less powerful lightning strikes?
As for the last one, the blimps could maintain their altitude at the breathable level.

 

[qraal]

Just hope the magnetic field that seems to be a feature of Jovian planets is absent for some reason. Otherwise no serious biological molecule will remain intact for long.

Huh?

 

[Chalnoth]

Could it be possible for a jovian planet to have an oxygen atmosphere breathable by humans?
Let's say that the humans live in blimp-like stations, and the jovian planet is small like Neptune to reduce the high gravity.

I don't think so. One problem (among others people here have mentioned) is the abundance of the various elements. It's very, very easy to make a big planet that is mostly hydrogen and helium (because most of the matter in the universe is hydrogen and helium). It isn't so easy to make a big planet that is mostly made up of elements like nitrogen, oxygen, and carbon: these aren't quite so common, because they are mere stepping stones to the most stable element, iron. When the heavier elements like oxygen and carbon are thrown out into the galaxy as a result of a supernova, they tend to come along with other heavy elements like iron. So it would be very, very difficult to get a planet that has lots of oxygen, but not also a lot of rock to go with it. Perhaps not impossible, but very difficult nonetheless.

 

[qraal]

Could it be possible for a jovian planet to have an oxygen atmosphere breathable by humans?
Let's say that the humans live in blimp-like stations, and the jovian planet is small like Neptune to reduce the high gravity.

The short answer is: No.

The long answer is more complicated. Planets could form large oxygen atmospheres from solar radiation (EUV and solar-wind) decomposing an ocean - Venus is believed to have had an oxygen atmosphere perhaps a hundred times thicker than Earth's as its hydrogen was lost en masse to space and this could happen to an Ocean planet. BUT it would be much too hot to be breathable.

There are Earth-like models of Ocean Planets, but they aren't Gas Giants as such. Such planets would undergo hydrogen-loss and build up large, thick atmospheres of nitrogen from ammonia photolysis. Oxygen from decomposed water would probably react with any methane and form carbon dioxide, huge amounts dissolving and precipitating in the ocean. Alternatively hydrogen and nitrogen could coexist, as they are believed to have done on the early Earth.

What isn't possible is a build up of oxygen when there's lots of hydrogen around - the two react too readily for large amounts of both. Nitrogen will coexist with either, but hydrogen (and methane) won't last around oxygen. Either hydrogen dominates and any oxygen reacts with it to make water, or there's a net hydrogen loss so free oxygen can build up.

There is one other option. A gas giant could be engineered with a breathable atmosphere. Take Neptune or Uranus - both contain large amounts of carbon. Wrap the bulk hydrogen/helium of a Gas Giant in that carbon, reformed into a shell of diamond. Then place your breathable habitat above that.

 

[Nicodemus]

Yeah, what I was trying to say is more what qraal is getting at with more skill and knowledge. Jovian planets are not hospitable to human life, regardless of the technology employed. I mean, these are people in your story right?... so, why are they colonizing the human equivalent of hell, given so much tech?

 

[FtlIsAwesome]

This is something I should have noticed before:
Equatorial surface gravities (g)
Jupiter 2.528
Saturn 1.065
Uranus 0.886
Neptune 1.14

Source: Wikipedia

I won't have to worry about surface gravity anymore. And I can even make it like Saturn and give it rings! As for the other problems, you are saying that it is the leftover hydrogen and helium, and the high temperature?
Humans can breathe helium, but an oxygen-helium mix would probably separate into low and high altitude bands, respectively.
The heat can be managed by placing it further from the sun. If were talking about heat generated by the interior, hmm. Ideas?

I would like this planet to be as habitable as possible prior to people visiting it.
This type of planet need not be common, as the minimum I want is one, ie. explanation of unlikely planet as one-in-ten-thousand.

This how I came up with the idea: research station in low-orbit over gas planet-->blimp station in atmosphere-->hey, let's make the atmosphere breathable! that'd be so cool!

 

[Nicodemus]

If I had to fashion a colony, while I can't say that qraal's ideas aren't ficitonally possible, I'd just mash together some small rocky planets, and essentially build an Earth 2.0. It seems easier to build a colony and deal with that, than it would be to harness forces that even a suicide probe can't handle.

I like qraal's inverted Dyson Sphere though... I like it a lot.

 

[FtlIsAwesome]

I'd just mash together some small rocky planets, and essentially build an Earth 2.0. It seems easier to build a colony and deal with that, than it would be to harness forces that even a suicide probe can't handle.

The blimps would float at roughly 1 atm altitude. Even with materials that can withstand higher pressures, people can't.
Unless your talking about heat, lightning, and/or storms. Hmm.

But actually building a planet is pretty interesting. Something for another thread.

 

[Nicodemus]

OK, if we're going full sci-fi, I'm in for that. Hell, I don't even mind the improbability of qraal's solutions if it made sense within the narrative.

I wonder... could you build a planet with a sufficiently hot (radioactive and literally) core, and the proper tectonics for a colony? Could you even "cook" it so that it generates its own atmosphere, much like Earth?

Maybe something like Larry Niven's "Fleet of Worlds" from the Ringworld series would make sense as well. As for blimps, I'd still say that's one hell of a narrow margin, and I'm not sure that breathable air would be found in that band.

 

[qraal]

Humans could live on low mass Gas Giants happily - gravity is pretty low on Saturn, Uranus and Neptune compared to Jupiter - but the implicit question was could its atmosphere be naturally breathable. It can't. Chemistry means hydrogen and oxygen just like each other too much. We could breathe a non-flammable mix of H/He/O up to fairly high pressures, but the oxygen has to be added.

 

[FtlIsAwesome]

What possible natural mechanisms could decrease the amount of hydrogen to non-flammable levels? The only one I can think of is using a smaller jovian which allows the hydrogen to escape into space.

 

[qraal]

What possible natural mechanisms could decrease the amount of hydrogen to non-flammable levels? The only one I can think of is using a smaller jovian which allows the hydrogen to escape into space.

There is one possibility, but the planets wouldn't strictly be Gas Giants. Gas Giants are, by definition, composed of mostly Hydrogen & Helium - Uranus & Neptune are classed as "Ice Giants", with a 'layer' of H/He. But the kind of planet I'm thinking of could be composed of just elements originally in "gaseous" form - carbon monoxide planets. These can be produced via disruption of white dwarfs. If some of the carbon separates to make a diamond crust, then a thick O2 layer would form on top. Such a planet might then gain some water and nitrogen from comet materials captured later. The internal structure would be denser states of C & O, perhaps in a "polymer" like form, such as the proposed "carbonia".

 

[FtlIsAwesome]

The heat can be managed by placing it further from the sun. If were talking about heat generated by the interior, hmm.

Now reading over qraal's post, he was talking about Venus. My bad.

The scenario can be divided into two:
1. A jovian planet with oxygen atmosphere that humans can breathe with little to no difficulty.
2. A jovian with a moderate-to-large amount of oxygen but is not breathable.

Probably I'll just use number 2 and they begin terraforming it, and people currently need masks when exposed to the environment. It'll likely be a small research colony, rather than a full-blown colony.

What would the appearance of an oxygen-jovian be from space (bands, no bands, color)? What would its sky look like from within the atmosphere?

If it helps any, I'll set some of the planet's properties, though I'm not sure if they'll work for an atmosphere containing oxygen.
Radius ~40,000 km (compare to Saturn's 54,300 km and Uranus's 25,600 km)
Surface gravity ~1 g
Mass 2.3x10²⁶ -- 38 MEarth (compare to Saturn's 95.2 MEarth and Neptune's 17.1 MEarth)

 

[qraal]

Ok. Heliox atmosphere needs some vigorous hand-waving to justify if you want a seriously possible exoplanet. Basically the oxygen has to come from photo-dissociated water, the hydrogen has to escape and the helium has to be retained, somehow. Then the planet has to be returned to a habitable orbit so you can have an open-air "gas giant" for airships with humans. Here's my rough guess. First the helium has to rain out and hydrogen get left behind. Then, via migration, the planet gets too close to the star and gets broiled, so the hydrogen is driven off and water is dissociated. Then the helium seeps out of its deep haven to produce a heliox atmosphere, perhaps underlain by a super-critical water atmosphere or some bizarre super-phase of something that mixes nicely with helium, but doesn't oxidize easily so it doesn't use the oxygen. The gas layer might be sufficiently thick to make it a research task of the floating colony, trying to figure out why the helium was retained so efficiently.

As for size, a pure helium planet is, at most, 42,000 km in radius and heavier elements mean the planet is smaller.

 

[Chalnoth]

Ok. Heliox atmosphere needs some vigorous hand-waving to justify if you want a seriously possible exoplanet. Basically the oxygen has to come from photo-dissociated water, the hydrogen has to escape and the helium has to be retained, somehow. Then the planet has to be returned to a habitable orbit so you can have an open-air "gas giant" for airships with humans. Here's my rough guess. First the helium has to rain out and hydrogen get left behind. Then, via migration, the planet gets too close to the star and gets broiled, so the hydrogen is driven off and water is dissociated. Then the helium seeps out of its deep haven to produce a heliox atmosphere, perhaps underlain by a super-critical water atmosphere or some bizarre super-phase of something that mixes nicely with helium, but doesn't oxidize easily so it doesn't use the oxygen. The gas layer might be sufficiently thick to make it a research task of the floating colony, trying to figure out why the helium was retained so efficiently.

As for size, a pure helium planet is, at most, 42,000 km in radius and heavier elements mean the planet is smaller.

I somewhat suspect, however, that the helium would burn off before the water dissociated.

 

[qraal]

I somewhat suspect, however, that the helium would burn off before the water dissociated.

Thus the hand waving about rain out into the deeper layers. A super-Neptune with relatively high levels of ices, but big enough for helium to become soluble in hydrogen or something. Big unknowns inside such beasts.

 

[ladykrimson]

I know I am a bit new here, but doesn't Jupiter have strong radiation? NASA tried to send a ship into Jupiter, but it couldn't keep functioning because of the radiation...or am I mistaken?

 

[FtlIsAwesome]

I know I am a bit new here, but doesn't Jupiter have strong radiation? NASA tried to send a ship into Jupiter, but it couldn't keep functioning because of the radiation...or am I mistaken?

This question was brought up earlier.
True, Jupiter has a strong magnetic field that would be harmful to humans without radiation shielding, even humans living on the moons. But Saturn has a magnetic field weaker than Earth's. We are assuming that the hypothetical oxygen-jovian has a magnetic field equal to Earth's.

NASA did send a probe into Jupiter, which relayed information until it was destroyed by the high pressure as expected. I don't know how Jupiter's strong magnetic field affected the probe.

 

[FtlIsAwesome]

As for size, a pure helium planet is, at most, 42,000 km in radius and heavier elements mean the planet is smaller.

So the planet needs to be smaller? Now thinking about it, it will need to quite small to lose the hydrogen.
Maybe 20,000 km would be better??

 

[qraal]

This question was brought up earlier.
True, Jupiter has a strong magnetic field that would be harmful to humans without radiation shielding, even humans living on the moons. But Saturn has a magnetic field weaker than Earth's. We are assuming that the hypothetical oxygen-jovian has a magnetic field equal to Earth's.

The magnetic field isn't harmful or dangerous, but the high energy particles circulating in it - as "radiation" - have sufficient numbers & energy to be deadly without adequate shielding. But that's only in the space around Jupiter, not in the planet's atmosphere.

NASA did send a probe into Jupiter, which relayed information until it was destroyed by the high pressure as expected. I don't know how Jupiter's strong magnetic field affected the probe.

That was "Galileo's" Entry Probe, which was destroyed by the rising temperature - it was over 120 C by the time the probe failed. Jupiter's atmosphere gets incredibly hot, the deeper one descends into it. For example at the 1 bar pressure level the temperature is 165 K (-108 C), but by the 22 bar level the temperature hits +400 K (+120 C.) Not much deeper down and the atmosphere is hot enough to melt most metals.

 

[FtlIsAwesome]

To dig this thread up a third time...


How will the properties of the parent star affect the planet? So far I have been assuming a G class of similar size/mass as the Sun.

Will the presence of moons affect the planet?
Can the jovian strip an oxygen-containing atmosphere from a moon to add to its own oxygen atmosphere?
This will require a small jovian (which we already have it set as) and a large moon with a thick atmosphere very rich in oxygen, higher than humanly breathable. When the jovian strips the atmosphere, the jovian's oxygen levels increase but still remain lower than what is necessary for humans.
Possibly an impact event or multiple impacts set the moon on a highly eccentric orbit, the oxygen atmosphere is blown to the jovian, and the moon is broken apart by the combination of impacts and tidal stress. The pieces of the moon then form a ring.


I think there's something wrong in my moon impact scenario somewhere...

 

[qraal]

To dig this thread up a third time...


How will the properties of the parent star affect the planet? So far I have been assuming a G class of similar size/mass as the Sun.

Will the presence of moons affect the planet?
Can the jovian strip an oxygen-containing atmosphere from a moon to add to its own oxygen atmosphere?
This will require a small jovian (which we already have it set as) and a large moon with a thick atmosphere very rich in oxygen, higher than humanly breathable. When the jovian strips the atmosphere, the jovian's oxygen levels increase but still remain lower than what is necessary for humans.
Possibly an impact event or multiple impacts set the moon on a highly eccentric orbit, the oxygen atmosphere is blown to the jovian, and the moon is broken apart by the combination of impacts and tidal stress. The pieces of the moon then form a ring.


I think there's something wrong in my moon impact scenario somewhere...

A moon in-spiralling to break up into billions of pieces isn't impossible, but the fate of its atmosphere is dubious, since the gas is mostly in orbit. The only easy way I can think of is if a Trojan planet is stripped of hydrogen, leaving ~200 bars of oxygen. It then is perturbed into a near-collision with the Jovian, breaking up into the ring and dumping a fraction of its mass into the atmosphere. The Jovian is rich in helium, but depleted in hydrogen after migrating outwards from a stellar roasting orbit.

 

[FtlIsAwesome]

but the fate of its atmosphere is dubious, since the gas is mostly in orbit.

Yes, this is what I thought was wrong with the scenario. The atmosphere might vent into space instead of being collected by the jovian.
What would happen if the terrestrial object went on a direct collision with the jovian?