How can someone breathe in a place without gravity? Doesn’t it take a vacuum in order for there to be no gravity and if this is the case, wouldn’t that vacuum take away all the oxygen from the place that would be without gravity? I see videos with astronaunts in space floating around with no gravity, but have their helmets off. How is this possible and still be able to breathe. I just don’t understand how the space ship would have oxygen and no gravity.
The presence of oxygen has nothing to do with gravity. You can get a zero-gravity condition, temporarily, by going up in an airplane and taking a steep dive (NASA owns a plane, called the “Vomit Comet”, that is used for training purposes in this manner).
I don’t want to get too deep into the discussion because I am not a physicist and I might say something stupid. Most likely a real physicist will be along any minute now 
-Andrew L
The vacuum is outside the spaceship, and you don’t see astronauts outside the spaceship with no helmets on do you?
oh, and strangely enough, there is plenty of gravity in space- what isn’t in space is anything to stand on…
except planets of course
I’m not sure if you’re being technical or misinformed.
Technically yes, because (according to Einstein) all mass warps space and creates a gravitational field. So to truely have absolutely no gravity you have to have no mass.
But if you just mean (practically) zero-G like in NASA films, then air pressure has absolutely nothing to do with it.
True. But you could be at the center of mass of a free-floating cloud of oxygen (until it dissipated away) and you would be subject to no net gravitational force.
Ok, so how can you get something to have no gravity? Like how could I make my house gravity free?
Put your house in orbit around the Earth, or, for a short-term solution, push it off a cliff (zero-G will stop once the house hits bottom). That’s about it, really. Currently, there is no way to shield an area from Earth’s gravitational field.
You could also move it to the center of the Earth.
Now come on, that’s pretty impractical. At least it’s possible to push a house off a cliff.
To literally make it “gravity free”, you’d need to move to a completely empty universe. Which would make breathing a bit difficult, among other things.
Now, if you want merely to be in a 0g environment, though, that’s a lot simpler. You just need to get your house in free fall. You’d put it in orbit around a massive object, presumably the Earth. When you get it’s orbital velocity up to a value v such that v[sup]2[/sup]/r = g, then you’d be in free fall.
Lessee, it’s been a while. g = G m[sub]e[/sub]/r[sup]2[/sup], so v = sqrt(G m[sub]e[/sub]/r), where G = 6.673e-11 Nm[sup]2[/sup]/kg[sup]2[/sup] and m[sub]e[/sub] = 5.976e24 kg. So, then for any distance from the Earth r (I’d recommend a distance of at least 6.4e6 m to avoid a nasty rug burn, preferably more), you’d need a velocity (in meters per second) of approximately 2,000,000/sqrt®, r in units of meters. Give or take a factor of ten. I said it’s been a while.
You’d also want to equip your house with booster jets to adjust its velocity to compensate for the sun’s and moon’s masses perturbing its orbit. Not to mention totally redoing your ventilation system.
And don’t forget to fill out those Change-of Address cards.
Now correct me if I’m wrong but if he wanted to very literally make it “gravity free” wouldn’t he have to find a way to construct it out of particles that have no mass? Since any object with mass has at least some gravitational attraction even in an otherwise empty universe his house wouldn’t be gravity free. Maybe he could use neutrinos for this gravity free house, built in the otherwise empy universe. I’m not quite sure how one would go about constructing anything out of neutrinos though since we have enough problems even detecting their existence much less getting them to sit still long enough to be made into a house… Oh then of course once he enters the house neutrino house it would no longer be gravity free since his mass will have it’s own gravitational attraction… Hmm doesn’t look like there’s really a way to escape the bonds of gravity.
No, he’d have to make it in a completely empty universe. Massless particles, assuming they are to mean anything, still have to have energy and momentum, and that means, in fact, that they have to gravitate.
So how does NASA have a room that has zero gravity to train their astronauts?
That’s how.
Photons have no mass (see some other General Questions thread). You could just live in a lighthouse.
Doesn’t NASA have an actual room that has zero gravity? If so, how is it like this? I know it isn’t just the room of a plane called the “Vomit Comet” taking a steep dive.
NASA has no such room.
I think that some researchers once levitated a frog, though, using magnetic fields. That must’ve been a trip.
No, the only zero-G environments NASA has are the so-called “Vomit Comet” and vehicles in Earth orbit. They do use a large pool to simulate zero-G for practicing missions, but it’s not a perfect simulation.
OK, thanks. I guess I was just misinformed about it then. But it would be kewl to be able to make a room with zero gravity.