Is it theoretically possible for there to exist someplace in space where I could float around in shirt-sleeves & shorts - and not be w/in some planet or planet-like object’s atmosphere?
I would need to be someplace where the surrounding gases were roughly of the same density, pressure and temperature of Earth’s atmosphere.
Could such a place exist? I don’t want to be too close to a star obviously, nor do I want to be w/in the atmosphere of a planet, or even a proto-planet type object. I don’t want to get fried with radiation, and I don’t want to get sucked into a planet or some other thing. I want to just float around a while. Even better, I’d like the composition of this gaseous place to have just enough nitrogen & oxygen so I could take off my breathing mask at least temporarily.
If such a place exists, would it still be considered “space?” Would such a place always be associated with too much dangerous radiation or w/in the gravity well of a planet, etc?
Well, I’d say the spot most like you describe is inside the International Space Station. Sure, you wouldn’t be very far from the walls when you’re floating, but it fits the criteria.
On the other hand, you could read Larry Niven’s The Integral Trees and the sequel, The Smoke Ring. He describes a ring of gas around a star which manages to support life while all in freefall. I don’t think you’ll find an actual place like that, but it could just barely happen.
A small cloud of gas floating in space will disperse very quickly. A large cloud will collapse by gravity. There is no stable equilibrium possible, but an unstable equilibrium may last a while. My guess will be that if you create such a cloud, it will remain habitable for centuries, but not long enough for life to evolve.
But you specified a breatheable atmosphere. There’s not much chance of that happening naturally. Space is mostly hydrogen. To get a nitrogen atmosphere you need a selective process that lets lighter elements escape, like a planet with a moderately strong gravity. Oxygen on earth is created by photosynthesis.
The “gas clouds” you see on Hubble pictures are nowhere as dense as our atmosphere. They’re as dense as a high-grade vacuum created in laboratories, maybe less.
For a fictional exploration of this, see Larry Niven’s “Integral Trees” and “The Smoke Ring” novels.
The basic premise is that every massive body with an atmosphere has a gas torus in it’s orbit…gases that escape from the planet are still in orbit around the primary.
Niven imagined a Neptune sized body orbiting a neutron star. The entire atmosphere of the planet is in orbit around the neutron star, creating a huge torus of zero-gravity gas, conveniently reaching 1 atmosphere at the center. Also conveniently, life evolved in the torus, so the torus has free oxygen. The whole torus is orbiting a conventional star for photosynthesis.
So such a thing might be physically possible, if you are allowed to hand-pick the starting conditions.
So I absolutely have to have photosynthesis to have dense enough oxygen & nitrogen to breath?
Ok, I understand gases each have their own “weight.” On Earth, we have gravity holding our gases close to the ground. Earth’s rotation & temperature fluctuations keep the oxygen & nitrogen well mixed.
I’m rusty on my old SCUBA training, but I seem to recall humans can breath more or less “pure” oxygen or nitrogen gas at least temporarily, right? But I’ll never get these gases dense enough in space without a pretty significant exertion of gravity?
So I’m not going to find a gaseous environment suitable to my needs “in space” and not within something’s atmosphere. I’ll nix that idea.
Could I find something in space with a gravity well such that it could hold oxygen/nitrogen at a layer, or “altitude” where I could still float around at least temporarily without getting immediately drawn into the central object and/or fried by radiation? Or in order to get the required density, the gases pretty much have to be well contained close to this object’s surface? In other words, if I’m breathing without assistance, I’m probably standing on the surface of something?
I know interstellar clouds of gas are only slightly denser than a vacuum. But stars & planets form from these clouds. Along the way from “vacuum” to “stars & planets” we must have a wide range of densities & temperatures. Nowhere in there is a point of relatively safe shirtsleeve “weather?”
Let’s look at gas giants. When I’m in orbit around one, I can float freely. As I get closer, the gases get warmer & denser, but eventually I’m plummeting to my death. Is there a point where the gases can be dense & warm enough and I’d still be able to float around? Let’s forget Niven & his oxygen producing organisms & the breathable part (although that would be nice). How about just warm & dense enough to float around in shorts & sleeves, but with a breathing mask?
The trouble is, you can’t be in a stable orbit and still be inside the atmosphere of a body. If you are inside the atmosphere, friction from the air will slow you down and cause you to lose altitude. On the moon you could orbit only a few feet above the surface (assuming you don’t hit a hill), because there is no air.
Now, why do we say that you need photosynthesis to get oxygen? Well, it’s because pure oxygen is so reactive. If all plants on earth stopped photosynthesising, the oxygen in our atmosphere wouldn’t stay there. It would combine with (oxidize) other things. This is happening all the time, and only the constant addition of new oxygen keeps free oxygen in our atmosphere.
You don’t need photosynthesis for a dense atmosphere, look at Titan.
The main trouble is this. Without a gravity source to hold the gas together, it will tend to disperse into space. A nebula is a gas cloud so large that its own gravity holds it together, but gas pressure still makes it very diffuse. Increase the mass enough and the gas cloud will start to condense into denser and denser pockets. These will form gas giant planets, or if large enough stars.
I don’t think there’s any combination of mass where you could simply have a free floating 1 atmospheres. The gas would either disperse into space, or condense into a gas giant planet or star. You need to do tricks like the gas torus to make it work. But, I suppose there’s a time window when a nebula collapses where parts of it are at 1 atmosphere. I don’t know how long that period would be…minutes? Hours? Days? Years? And I also have no idea what the temperature of the gas would be.