Hypothetical question… :
What would happen if we all went to sleep one evening and the next morning the world wakes up zero gravity. Gravity has completely removed from earth.
Would our buildings start floating? Presumably our cars would float?
What would happen in the event that suddenly there was no gravity on earth (one second you have it and the next boom its gone)
Gravity is the only thing holding the Sun together, so it would disperse into an expanding cloud of plasma. It will probably engulf the earth in a few days.
But we probably won’t be around to notice, because the Earth’s atmosphere will immediately start dispersing into space. Shortly after that, all the liquid water boils away.
Not to mention that the instant gravity ceased, everything that wasn’t tied down would be flung into space at around 1,000 mph - the rotational speed of the surface of the earth…
You would wake up, and have maybe milliseconds to figure out what was going on as the air is ripped out of your lungs and you are thrown into your ceiling and then your wall at hundreds of miles an hour.
Also gravity is the only thing holding the Earth together. Matter deep down is compressed more than it “wants” to be by miles of matter above it. Remove the gravity, the matter would expand (not sure at what rate.)
Good point. Actually, the earth’s crust probably doesn’t have the tensile strength to withstand the centrifugal force. The whole planet would just disintegrate into an expanding ring.
You, your house, and the ground would all be thrown out into space at roughly the same velocity, so you’d be spared the impacts. The atmosphere would fly into space, but you’d have a little time* to notice before it got too thin to breathe.
*Both the speed of individual air molecules at typical ground-level temperatures and pressures and the speed of Earth’s rotation are on the order of a few hundred meters per second, so the air would dissipate into space at roughly that speed. Since the breathable atmosphere is a few kilometers thick, it would take a few seconds for the volume of the lower atmosphere to expand sufficiently to become unbreathable.
I figure the house being anchored to the earth would hold it down for just long enough to make all unsecured objects slam into and through walls before it came apart.
Good point on the air, I was thinking it would dissipate a bit quicker than that. So, you probably wouldn’t even notice that part.
Now, if you were outside, with nothing around to run into, then you would be launched into space at up to 1000 mph, depending on how close to the equator you were, so you’d be racing the air dissipation. You’d live maybe as much as 30 seconds, some of that even while conscious.
Go to the poles, and that’s where it will be a bit more interesting. You aren’t going to be flung off by rotational energy, but you will probably be sucked off along with the air. The earth under you would be expanding, as it rebounds from all the compression from gravity, probably at a pretty high rate, but I’m not sure where to even start on calculating that one.
I am obviously ending the narrative at the death of the observer, bad things keep happening to pretty much everything after that. Assuming gravity never comes back, pretty much everything everywhere will disintegrate, and the universe would be full of particles and molecules, but not much sticking together past that.
Nothing is going to slam into walls. You and the house will continue to move towards the east at the same speed. If the Earth holds together, and the house remains anchored to it, the effect will be that you travel in a straight line while the house moves in a circle. So you hit the ceiling, not the wall.
If it were “zero G” in the sense that we’re all just floating – rather than being flung upwards! – things would be vastly more interesting…but still quite catastrophic withal. We’d lose stuff. Stuff would just float away. We’d have a dickens of a time retrieving stuff that gets away from us.
And many people would be lost, drifting upward and not able to get down.
(Could we “fly” by flapping our arms? Maybe. “Air swimming.” So losing your footing and floating upward might not be hopelessly bad.)
Cars, trucks, railroads, all stop working. Very bad new for our economy. Ships stop working. (Airplanes are still just fine!)
Hydroelectric generation stops working. Rivers stop flowing. (This is VERY bad for the environment. Also the economy.)
I have no idea what would happen to fields of crops. Would cornstalks still grow? Or would they die? Would seeds be able to figure which way to sprout? But even if crops grow, harvesting is going to be the dickens, without tractors and combines and things. If nothing else kills us off in large numbers, I’m afraid starvation would.
Air swimming in what?
Airplanes flying in what?
Both things require air density, of which there would be 0 after it all vents out into space:confused:
I was engaging with what I think was the ostensible hypothetical: what if we were suddenly in a “zero-g” environment.
Ceteris paribus and all. What if it’s the world, as we know it, but…there’s no “down” any more? The air doesn’t vent into space, because magic. (Which, of course, is also the only way the situation everyone else is engaging with could happen…)
OK, the magic is preventing the air from escaping, fine. What else is the magic preventing from happening?
So what else is “as we know it… because magic”? So the air is kept in place by some kind of force field, and the earth doesn’t fly apart by centrifugal force? Does the earth’s rotation stop? If not, what happens to every loose object that flies away from the ground due to centrifugal force? Would they get trapped by the force field? Would all this junk on the force field block the sun? I suppose all the liquid water would end up there as well.
If the rotation also goes away, I guess we’d survive for a while. But without gravity, there will be no flow of water and no rain, so it would be very difficult to grow anything. Anything that runs on liquid fuel and/or liquid coolant probably won’t operate correctly. Basically, any machinery that won’t work upside down probably won’t work.
You could fly around with a set of wings strapped to your arms, or maybe by holding a battery-powered fan in your hand. But the sky will be so full of floating junk that it may be risky.
Who knows? It isn’t preventing a zero-g environment, which is (I think) the hypothetical. So I chose to try to engage with it.
And, really, serious question, from Skylab and Space Station experience: can people fly/swim in zero-g?
You need the Virga series by Carl Schroeder.
That’s where I was trying to go. Can the OP come back and tell us if this was closer to what was envisioned?
Hadn’t thought of strap-on wings. But, yeah, floating junk. It might not even be possible to get around inside your living room any more, because of floating stuff, from sofas to little knick-knacks.
Another thought: there are some things that aren’t fastened down, but merely placed and held by gravity. Military tanks’ turrets, I believe, aren’t held down, but just set into their wells. I saw a TV show about the placing of the control island on a modern aircraft carrier, and it, too, wasn’t bolted down, but just held by gravity. Would these things be at risk of floating off if given a jostle?
(Telescope domes? Stadium domes?)
Anti gravity isn’t impossible to model, even though we know of no legitimate physical mechanism to achieve it. If you imagine a magic box that is an ‘anti gravity generator’, what the box must do is create some kind of field - like a magnetic field but it affects everything - that is countering the effect of gravity. So everything floats above the box. What if evil aliens have secretly tiled the entire earth’s surface with these magic boxes a few meters down?
Just like magnets, these magic boxes are subject to the forces of anything above them they are making “weightless”. Presumably what would have to happen is that above a certain altitude, the field would diminish. So in actuality, maybe 5-10 kilometers in the sky, if you were to float up that high, you’d feel gravity beginning to restore itself. There might in fact be a sky band where it’s 2G, this band would be pushing the air molecules and essentially ‘pressurizing’ the earth’s atmosphere.
So what would happen is that if you tossed objects into the air, they’d float up slowly, then eventually once they get to 5-10 kilometers, they’d hit a barrier and get pushed back down. There might actually be a steady downward breeze, I’m not sure.
Tank turrets and stadium domes would stay in place due to friction.
The real problem is of course it would be pointlessly long winded way for nearly everyone on earth to be killed*. I think a small number of survivors could survive indefinitely by crafting equipment that can run in the new environment. Or not. I’m now thinking of the entire oceans floating upwards and essentially making the earth an uninhabitable air/water mix.
*in some sci fi stories, that’s the alien’s goal - to create a sort of Darwinian environment so that only the cream of the crop may survive.
Going with your contention that “all” that changes is gravity but not atmosphere. FTR I agree you’ve got a different and more interesting scenario than the way everybody else took the OP. Near instant destruction of the atmosphere and the planet are exciting, but ultimately boring. Game’s over too soon.
Anyhow, ref the snip above …
Airplanes are designed to operate in 1G. Their whole schtick is staying aloft *despite *gravity’s endless attempt to make them fall out of the sky.
If gravity suddenly went away, an airplane in flight is going to start climbing uncontrollably. There may be enough maneuverability to dive enough to offset that climbing but there are no guarantees. I’d bet most airborne aircraft & pilots couldn’t figure out what was happening or how to counteract it quickly enough to get back on the ground successfully. It’s not clear to me they could land at all.
Not to mention the problem that once one did somehow arrive near a runway at near-zero altitude & speed, somebody would have to lasso the damn thing and tie it to the ground to keep it from blowing away. Just like blimps do it today. All without themselves drifting off.
All in all, even a zero G world that somehow retains an atmosphere (a giant forcefield dome 50 miles up above?) and an intact planet (a giant forcefield shell at ground/sea level?) still provides a shitload of obstacles to primitive life, much less modern tech-dependent life.
Gonna be weird is all I can say for sure. Weird and highly lethal to much of humanity until we sort out how to operate in the new reality.
No, they can’t. They can push off from a stable object and move themselves in a straight line around their center of gravity until something stops them. It’s not analogous to flying as birds do on earth.