# Why two mass attracts each other?

Discussion in 'Physics & Math' started by hansda, Mar 19, 2013.

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1. ### hansdaValued Senior Member

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This is from Einstein's Paper and Einstein's Equation E=mc^2. Einstein in his paper proved that "inertia of a mass is dependent on its energy content". So, we can write m=E/c^2.

Gravitational Force F=G*m1*m2/r^2 can be re-written as F=G(E1/c^2)(E2/c^2)/r^2 or F=(G/c^4)(E1*E2)/r^2.

"Strong Nuclear Force" keep proton and neutron together. This nucleus keep the whole atom together. So, "strong nuclear force" keep the "energy content(E)" of a mass(m) together. So, inertia of a mass(m) is dependent on "Strong Nuclear Force".

As "Gravitational Force" is dependent on mass(m), so it is also dependent on "Strong Nuclear Force".

3. ### eramSciengineerValued Senior Member

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Once again you're just loosely associating certain terms. It's too vague for anyone to assess.

5. ### hansdaValued Senior Member

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Where is your problem? All the terms F, G, E, c and m mean their usual meaning or you want their explanations also.

7. ### eramSciengineerValued Senior Member

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this is an example that is too vague

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9. ### eramSciengineerValued Senior Member

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So what if I read those? You're still too vague.

10. ### hansdaValued Senior Member

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So, mass of an atom is due to this "Strong Nuclear Force".

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13. ### Farsight

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There's no problem with that.

Or that.

This isn't quite right I'm afraid. The strong nuclear force keeps a proton together, the residual strong force keeps an atom together. And a body will lose mass if if emits a photon. That body can be a photon in a box.

I'm sorry hansda, it's dependent on energy. In Einstein's Foundation of the General Theory of Relativity he says "the energy of a gravitational field shall act gravitatively in the same way as any other kind of energy". The gravitational field itself causes gravity because there's energy in it, not because there's matter in it along with the strong nuclear force.

14. ### eramSciengineerValued Senior Member

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May not work out so well. Farsight has one follower here by the name of Dufoe.

15. ### hansdaValued Senior Member

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It was your question in post #93 about how "gravitational force" is related with "strong nuclear force".

As "gravity" depends on "mass" and "mass" depends on "strong nuclear force"; so, "gravity" depends on "strong nuclear force".

16. ### hansdaValued Senior Member

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Read my post #107 for wiki quote on "strong nuclear force".

I am not considering GR here but Newton's equation for gravity.

17. ### eramSciengineerValued Senior Member

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Ok, you've answered my question, I just want to reiterate that your statement is too vague. Do you have any other queries?

18. ### hansdaValued Senior Member

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If you are not satisfied, it is upto you.

19. ### eramSciengineerValued Senior Member

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I didn't have any request to satisfy, I was just giving you feedback. So I'll take that as a no.

20. ### Markus HankeRegistered Senior Member

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Wrong. It keeps the nucleus together, not the atom.
Now, it should be interesting to see whether this correction will result in a flurry of links and quotes trying to show how little I understand of physics

21. ### Farsight

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You're right Markus. I typed "atom" because it was in my mind after Hansda said "Strong Nuclear Force" keep proton and neutron together. This nucleus keep the whole atom together. Apologies for the error.

22. ### MeNotYouRegistered Member

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This is something I've always struggled with.
If all the large dimensions are accounted for....and gravity is literally all of spacetime(all 4 large dimensions) bending....don't you need another dimension for it to bend into? If spacetime(all 4 dimensions) is a line, and that line bends....by definition that line must exist on a 2 dimensional plane.

Am I correct to say, it's not the stuff IN spacetime that is bending...it's spacetime itself?

23. ### Farsight

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Not strictly. Strictly speaking, spacetime is an abstract mathematical space in which motion does not occur because it models space at all times. You can draw world-lines in it, and you can draw them curved, but that worldline represents the motion of a body through space over time. The body doesn't actually move through spacetime. People tend to talk of "the spacetime around the Earth" and suggest that light moves through it, but actually, that's wrong. Pay careful attention to Einstein's 1920 Leyden address where he said this:

“According to this theory the metrical qualities of the continuum of space-time differ in the environment of different points of space-time, and are partly conditioned by the matter existing outside of the territory under consideration. This space-time variability of the reciprocal relations of the standards of space and time, or, perhaps, the recognition of the fact that “empty space” in its physical relation is neither homogeneous nor isotropic, compelling us to describe its state by ten functions (the gravitation potentials gμν), has, I think, finally disposed of the view that space is physically empty.”.

Metric is to do with measurement. The metrical qualities of the continuum of space-time differ because space is neither homogeneous nor isotropic. You can get a handle on this by placing gedanken light-clocks in an equatorial plane through the Earth. The light-clocks run at different rates, and when you plot your measurements your plot is curved just like the wikipedia plot of gravitational potential which is like the bowling-ball-in-the-rubber-sheet pictures. But the light-clocks didn't run at different rates because your plot was curved, they ran at different rates because the space they're in is inhomogeneous. Google on inhomogeneous vacuum for more information.