# Is gravity a force or a lack of a force?

## Main Question or Discussion Point

My actual question is if gravity repels as well as pulls. I know, according to Newton's third law, that every action has an equal and opposite reaction. So can the force we label gravity actually be the result of the supposed empty space around it exerting pressure onto objects of mass?

[This question has been plaguing me as of late due to my swimmers ear.
I often lose balance when my inner ear goes off.]

This question probably sounds dumb to some, but I am new here so I was wondering if anyone had a quick answer.

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LeonhardEuler
Gold Member
Ilikemyname said:
My actual question is if gravity repels as well as pulls.
I don't believe it does. I haven't studied general relativity, but from what I understand it produces only minor changes in the expected behavior of gravity in most situations.
Ilikemyname said:
I know, according to Newton's third law, that every action has an equal and opposite reaction.
Yes. This simply means that if the sun pulls the earth with a force of so many newtons, then the earth pulls the sun with the same force. Niether repels the other.
Ilikemyname said:
So can the force we label gravity actually be the result of the supposed empty space around it exerting pressure onto objects of mass?
I don't see how a pressure force would behave like gravity. A pressure force would not cause the earth to accelerate because it presumably pushes with the same force in every direction.

So there are "dents" created by any amount of collected mass, which can be concidered fields. Any other mass's field that rolls through or overlaps the first mass's field, then their two fields interact with one another exerting gravity. These two fields... pull on each other? why?

Now I know that GR thing. Like a trampoline with bowling balls on them, but in order for that experiment to work you need gravity in the first place.

Is gravity because of the warped space? Or is the warped space due to gravity?

pervect
Staff Emeritus
Ilikemyname said:
My actual question is if gravity repels as well as pulls. I know, according to Newton's third law, that every action has an equal and opposite reaction. So can the force we label gravity actually be the result of the supposed empty space around it exerting pressure onto objects of mass?

[This question has been plaguing me as of late due to my swimmers ear.
I often lose balance when my inner ear goes off.]

This question probably sounds dumb to some, but I am new here so I was wondering if anyone had a quick answer.
The quick answer is no, gravity is not a repelling force.

See for instance the wikipedia article

http://en.wikipedia.org/wiki/LeSage_gravity

The only comment I have is that wiki was MUCH too kind to the cranks who are attempting to revive this dead horse of a theory.

I was wondering who had a good article on the pressure theory.
Thanks alot Pervect.
I hope you don't find me a crank, I was just wondering.

It is interesting to try at least a little to verify this idea. That gravity is a repeling force and the attraction between massive bodies has to do with some lack of repeling action through the distance that conects the two bodies.

Imagine a massive body is constantly being shot by small particles. So if it is isolated, it will be in equilibrium. But if another body enter as a shadow creator then attractio happens

Ilikemyname said:
Is gravity because of the warped space? Or is the warped space due to gravity?
I think it's correct to say "gravity because of warped space. Warped space due to the presence of mass," but I haven't studied GR either.