# How does zero gravity work?

## Main Question or Discussion Point

Zero gravity. We can hear about the zero gravity chamber , zero-g flights on aeroplane and lots of other stuffs about zero gravity on earth.

How does it actually works?
Can it be possible for us to make it?

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phinds
Gold Member
2019 Award
Can it be possible for us to make it?
Sure. Climb up on a chair and jump off. In the time from when you leave the chair to the time when you hit the floor, you will be in free fall ("zero gravity")

russ_watters
Mentor
Zero gravity. We can hear about the zero gravity chamber , zero-g flights on aeroplane and lots of other stuffs about zero gravity on earth.

How does it actually works?
Can it be possible for us to make it?
You're throwing together several different concepts (some possibly fictional), so it is difficult to know which you are actually asking about. I'll pick one: zero-g flights on airplanes.

The "g-force" you normally feel is due to the fact that you are opposing Earth's natural tendency to accelerate you at 9.8 m/s/s. That's what creates the force on your feet and through your body while standing. If you are in freefall, accelerating at 9.8 m/s/s, you feel zero gravity. So all an airplane has to do to simulate this is fly in a parabolic path, accelerating downward at 9.8 m/s/s, matching Earth's gravitational acceleration.

CWatters
Homework Helper
Gold Member
Zero gravity. We can hear about the zero gravity chamber , zero-g flights on aeroplane and lots of other stuffs about zero gravity on earth.

How does it actually works?
Can it be possible for us to make it?
Depends what you mean by zero. You can get very very close to zero gravity in free fall but any time you are near some matter there will be a small gravitational acceleration. So for example you will be very slightly attracted to other people on the zero gravity flight with you no matter how good looking they are :-)

sophiecentaur
Gold Member
Zero gravity. We can hear about the zero gravity chamber , zero-g flights on aeroplane and lots of other stuffs about zero gravity on earth.
Which is the correct answer to this question. I am confused.
You cannot get real 'zero g' near the Earth. Go to the deepest region of space and you will be a long way from any significant masses. The g there will be very near zero.
You can simulate zero g by moving in a curve (orbit or parabolic aeroplane path). You experience weightlessness there but g is still significant up there. If you erected a massive high platform for the vomit comet to fly over, the g at that height would be pretty much the same as g, measured on earth.
P.S. There has to be g, even as far away as the Moon (and beyond) or the Moon wouldn't;t stay in orbit.

ZapperZ
Staff Emeritus
Zero gravity. We can hear about the zero gravity chamber , zero-g flights on aeroplane and lots of other stuffs about zero gravity on earth.

How does it actually works?
Can it be possible for us to make it?
To make sure we are accurate in all of this, what you described is not a "zero-g" environment, but rather, a weightless environment. And you need to understand how you and I "feel" our weight.

When you are standing perfectly still on the ground, what you feels as "weight" is actually the reaction force of the ground pushing up against your feet. If you are in an elevator, and I cut the cables, you and the elevator will fall with the same acceleration, i.e. a = g = 9.8 m/s2. When this happens, the elevator floor no longer pushes up against you, and you do not "feel" your weight anymore, i.e. you will be floating inside the elevator. You are STILL in the earth's gravitational field, i.e. gravity is not zero. But you do not feel any reaction against your weight with the floor, so you feel weightless.

Turn this the other way around. If the elevator is floating in space in actual zero-g, and the floor of the elevator accelerates "upwards" at a = g = 9.8 m/s2, then you won't feel any different than " ... standing perfectly still on the ground... " on earth, i.e. you will feel your normal weight, even though you are in a true zero-g environment.

I've used this document when I taught free-body diagram and weightlessness concept to my students. Maybe it'll help you as well.

Zz.