Let’s suppose we could dump enough “breathable” air (whatever that means for humans) into the solar system that it filled the spaces between planets.
What would happen?
A - I imagine it would then become possible to fly airplanes between planets, perhaps balloons? Would space travel become easier or harder?
B - According to another lemmy post, we would start to hear sound waves from the sun (A constant jackhammer sound - delightful)
C - Each each planet become the center of some mega cyclone (like the Jupiter storms, but bigger)?
D - At some point the air above us wouldn’t be pushing down onto the earth at sea level, could we survive the additional pressure?
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This sounds like an XKCD what-if that ends with an explosion that could deafen god himself.
Like, if it just pops into existence, “static” relative to the sun, it’d all slowly fall into the sun. The solar system is ehhh 100 AU wide, atmospheric density’s about 1 kg per cubic meter, 1 AU is ~1.5e11 m… volume of a sphere is 4/3 * pi * r^3… that’d be 4.5e39 kg of gases, or basically 500,000,000 times the current mass of the sun. So, at a wild guess, probably enough to form a black hole? But it cannot be good for the inner solar system either way. Especially not if we work out how an Earth-shaped column of that gas falls into the sun with Earth in the way.
(Edit: Sagittarius A* is only 4e6 solar masses. 5e8 is borderline supermassive. Things would go poorly.)
If it spins instead - if it’s all playing nicely with the orbits of each planet and the general flow of the asteroid belt - we probably don’t all die fantastically. At least not for a while. We can assume it’d be a plane instead of a sphere, maybe 1 AU thick, as if the sun had rings. I don’t think it’d just diffuse out into the cosmos? Once all that mass is orbiting, you’d only lose the weird exceptional atoms that reach the edge with a bunch of energy and then don’t hit anything for a zillion miles. That also happens at the top of Earth’s atmosphere, and we’ve got gravity keeping it in check. So let’s just hand-wave that this situation lasts, like, at all.
Those bands in the rings will experience friction. Any speed differential has consequences, and I do not want to think about the computation requirements for that kind of fluid simulation. I think at worst they’d separate. They can’t all take the same angular velocity because that’s not how orbits work. They might fuck up the planets moving through them? Like, I don’t know much about astrophysics, but when a planet has rings it’s not because things went well for the satellites in that range.
Actually that highlights how the planets would have the same issue as the sun, if a bunch of mass magically appeared overhead, in their reference frame: it’d fall. Air doesn’t weigh much, but when you hand-wave an entire gazillion miles of it, that adds up. We’d have problems well before the atmosphere started to outpace the entire solid mass of Earth.
If this atmosphere orbits each planet, the way the whole shebang orbits the sun - you’re back to speed differentials. Just thinking locally: there’d be different spin for air that refuses to fall toward Earth, and air that refuses to fall toward the moon, and somewhere in the middle those two streams would meet. Or - at best! - they wouldn’t quite meet. The gaps would separate themselves. You could maybe do a cool sci-fi setting with that, but your space 747 would need to zoop clean out of Earth’s sky-ocean and catch the moon’s.
Oh. And I don’t think sunlight would be visible through one hundred and fifty million kilometers of atmosphere. At least, until the sun slurped up a couple yottatons of it, at which point we’d have whole new problems.
This would be a good xkcd what-if, right up Randall’s alley.
If you’re talking about Earth-like atmospheric density, I can tell you that that is a lot of mass.
So first off, if it’s not rotating, it’s gonna collapse into the Sun. And I’d guess, without looking at the numbers, that it’s probably gonna be some combination of processes that are gonna ultimately result in a black hole where the Sun is now.
If it’s rotating, then there’s a problem. You can’t just have air staying in orbit in arbitrary orbits, because it’ll collide. So I guess that you’d have to have a flat ring of gas, like Saturn’s rings. Basically, it’d have an orbit of zero eccentricity.
The planets don’t have an orbit of zero eccentricity, so they’d be smacking into air constantly. Aside from the effects of all of that air being captured by the planets themselves and adding to their mass, I’d guess that it’d tend to force them towards a zero eccentricity orbit.
If you have that gas ring, there may be more-dramatic near-term effects, but I would guess, again without looking at the numbers, that the planets would accrue it over time, and it’d have drastic effects on the planets; a lot of mass showing up, to say nothing of the chemical effects of oxygen and the thermal effects of colliding with the air.
It’d also add a lot of mass with rotational energy at orbital speed, so I assume that it’d make it easier for the Sun to capture stuff passing through that gas disc.
I don’t know what effects would be sooner or dominate, but I think that it’d probably be pretty exciting in more unpleasant ways than the flying airplanes between planets thing that you mentioned.
EDIT: Hah, did this before reading mindbleach’s comment, and he hit some of the same points.
Science values independent discovery of exactly how fucked we are.
I hadn’t considered foreign asteroids. If this ridiculous setup was somehow stable, bits of it would routinely light up from space rocks plunging through at terrifying speed. Hailey’s comet is coming back to stay.
Well, given a sphere of air stretching out to Neptune would only be around 6.5x its Schwarzschild radius in diameter, I imagine it would very quickly collapse into a black hole. There definitely won’t be enough time to fly airships around or hear the sound from the Sun before the planets are shredded by the air (which is moving at roughly Mach 80 in the case of Earth), even if they didn’t fall into the new black hole.
Lots of fire
that’s roughly a protoplanetary disk, what it’s like before new planets form! jupiter’s mass is 95% hydrogen-helium atmosphere with a core of ice and metals. because the solar system already has planets, though, we’d expect the ones currently here to “sweep” up the gas along their orbits in a fairly timely manner (jupiter’s year is 12 earth-years). if the gas is spinning at about planetary speeds, most of the gas will gradually be pulled out of solar orbit and into planetary atmosphere, so basically all the planets will become gas giants (or possibly new dwarf stars! i haven’t done the math). depending on how far out your protoplanetary disk goes you might need new planets form in the outer regions, past the regions where existing planets have formed. expect orbits to get really fucked up due to new gravity dynamics.
so for your questions:
A: yes, you should have enough air pressure to leave orbit in a plane, which is great to flee the planet because the new solar atmosphere will immediately plunge earth into an ice age for a few years as it first blocks most of fhe solar radiation, and then gradually heats up. the solar atmosphere wind dynamics will also fuck you up in a way that the dying Earth’s scientific computing will struggle to help with, especially when all satellites burn up in air and fall to the surface
B: (1 AU / the speed of sound) = 5000 days. the distant, ominous howl of a vengeful sun will be the least of your concerns as the nations of earth turn violent in a desperate attempt to save some last trace of human civilization
C: a megacyclone, yes! a beautiful spiral as each planet sweeps up the protoplanetary gases to swell to gas-giant size or dwarf star status. perhaps some day the light of five suns may shine on Earth again, but all traces of what once was will be sunk under five thousand kilometers of a liquid nitrogen sea. in one possible delusion, the billion-year descendants of the last earthlings will live in orbit of a still-molten rock so far past the kuiper belt that the five stars of Sol look like a bright-hot constellation instead of the core of its orbit
D: at some point, yes! for a brief moment the pressure will be unchanged as the solar atmosphere orbits the sun instead of pressing on the earth. perhaps some would be wise enough to realize that the sudden dimming of the sun - eight minutes as it turns to a dull, occluded, sky-colored haze, as if it had just melted away - foretold an imminent disaster. those bright minds would struggle to be heard amid a hundred other apocalyptic visions, because who would believe the sudden, impossible appearance of so much mass? but maybe some would have the sway and the speed to take their calculations to an appropriately powerful spaceplane, or a convenient tanker aircraft, and set off before the earth’s mass doubles in a year, then doubles again, like a snowball of oxygen rolling around in the deepening winter.
perhaps some would be wise enough to realize that the sudden dimming of the sun - eight minutes as it turns to a dull, occluded, sky-colored haze, as if it had just melted away -
Huh. If it all snapped into existence, it’d catch the light traveling through space, at that moment. So Earth might briefly get brighter? The dark side obviously would, as Rayleigh scattering turns our penumbra blue… all the way out to fucking Neptune. On the bright side, at first, it would genuinely be more sky, but-- I don’t-- I just cannot wrap my head around how to even model that. The entire solar system would flash as bright as the daytime sky, give or take a couple AU, for like a billisecond. And then that energy would bounce around until it’s mostly absorbed, surely. The image of the sun might vanish instantly. Even on Earth I expect most photons do not arrive having dodged the entire atmosphere.
Thinking about modeling this ridiculous hypothetical is going to keep me up tonight.
I’ve been thinking about this alot, so if we change the scenario to the solar systems collides with a huge cloud of air just drifting in space, we would see the blue sky on the moving interface as the air spreads though the solar system.
It’s quite magical in the minds eye.
Gradually gliding into a gaseous cloud that the sun lights up would be genuinely fascinating, but still probably kill everyone. Pros and cons.
… would it affect the northern hemisphere first? I have no idea which direction the solar system actually proceeds.
most everything in the milky way galaxy is orbiting the center of the galaxy clockwise relative to our north*, so we’d probably enter the gas cloud from the side by drifting into it faster than it is moving
*that’s orbital north, the direction that’s perpendicular to orbit and close-ish to the magnetic north pole (which is tilted relative to the orbit)
A - space travel would be harder. The difficulty with travelling into the solar system is gravity, not the vacuum. You would still need to launch something with enough energy to escape the earths gravity. Aeroplanes are not escaping earth’s gravity - they’re constantly using fuel to stay a certain distance from the earth’s surface but they do not have enough energy/power to reach escape velocity.
So if you filled the solar system with gas you wouldn’t fix the gravity problem. What you would do is add more friction which would cause drag on space ships, and slow travel between destinations as well as require even more fuel than present. Once a ship is in space currently, “aerodynamics” is not an issue; it’s all about gravity and velocity. Throw in air, and you have new problems in drag, shape and as a result likely fuel consumption to stay on course or reach as far as you want to.
Not exactly. All known means of propulsion are based off of throwing something backwards to propel yourself forwards. In a medium like air, you can grab the air in front of you and thrust it behind you. In space, you don’t have that option, you have to carry all of the propellant with you from the start and can’t get more unless someone brings it with you.
