Is gravity a fundamental property of mass and space?

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Discussion Overview

The discussion revolves around the nature of gravity, specifically whether it is a fundamental property of mass and space, and how mass influences the curvature of space-time. Participants explore concepts from General Relativity, the relationship between mass and gravity, and the implications of these ideas on the speed of light.

Discussion Character

  • Exploratory
  • Technical explanation
  • Conceptual clarification
  • Debate/contested

Main Points Raised

  • Some participants question why mass causes the distortion of space-time, suggesting it may be a fundamental property of space.
  • There is a proposal that gravity could be viewed as a form of friction preventing mass from achieving the speed of light.
  • One participant emphasizes the importance of understanding General Relativity, noting that gravity is a distortion of space-time rather than just space.
  • Another participant mentions that massive objects curve space-time due to their energy, referencing the stress-energy tensor as the source of this curvature.
  • Concerns are raised about the understanding of mass, with participants seeking clarification on its definition and implications in the context of relativity.
  • There is acknowledgment that the Einstein field equation (EFE) is postulated and fits observational data, but the underlying reason why mass curves space-time remains unclear.
  • Participants express a desire to learn more about the mathematical foundations of these concepts, particularly regarding the energy associated with mass and momentum in relation to space-time curvature.

Areas of Agreement / Disagreement

Participants do not reach a consensus on the fundamental nature of gravity or the reasons behind mass's effect on space-time. Multiple competing views and uncertainties remain regarding the interpretation of gravity and its relationship with mass.

Contextual Notes

Discussions include references to General Relativity, the stress-energy tensor, and the implications of special relativity, but there are unresolved questions about the nature of mass and its role in gravity. Some participants express a need for further understanding of the mathematical aspects involved.

Who May Find This Useful

This discussion may be of interest to those studying physics, particularly in the areas of General Relativity, gravitational theory, and the relationship between mass and space-time. It may also benefit individuals seeking to deepen their understanding of the fundamental principles of gravity.

Evan
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I understand that the distortion of space is what gives rise to the force of gravity and the Earth is basically stuck in the suns distortion but why does mass cause this distortion. Is it just a property of space that is fundamental or can there be a reason why it causes the distortion and, with more technology and advancements, could be counteracted?

Also if gravity is a property of all mass is it possible that gravity is a friction that keeps mass from ever achieving the speed of light?
 
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Evan said:
I understand that the distortion of space is what gives rise to the force of gravity and the Earth is basically stuck in the suns distortion but why does mass cause this distortion. Is it just a property of space that is fundamental or can there be a reason why it causes the distortion and, with more technology and advancements, could be counteracted?

Also if gravity is a property of all mass is it possible that gravity is a friction that keeps mass from ever achieving the speed of light?

You should not try to "extrapolate" an idea when that idea isn't well-understood in the first place. Proposing "gravity is a friction" falls under that description.

I think you haven't fully understood General Relativity. It isn't a "distortion of space", but rather a distortion of space-time. So I would recommend a simple introduction to General Relativity for you to read (assuming that you already know about Special Relativity and the connection between space and time):

http://www.physics.fsu.edu/courses/spring98/ast3033/relativity/generalrelativity.htm

Zz.
 
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what do you mean by "mass"?
 
I did understand that it was space-time but I was wondering why mass effects it.

I will read that though because it will probably help me understand it better at least the concept. I'm good with my calculus but I need to work my way through more of the physics before GR.
 
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HallsofIvy said:
what do you mean by "mass"?

Massive objects in space. Special Relativity says matter with mass can't go the speed of light. I kind of want to know why rather than making a right triangle with E=mc^2+pc. I have read that the higgs field is what keeps particles with mass from going the speed of light but why?
 
Evan said:
I did understand that it was space-time but I was wondering why mass effects it.

Particles are necessarily coupled to the metric.
 
Evan said:
I did understand that it was space-time but I was wondering why mass effects it.
Mass curves spacetime because it has energy and the stress-energy tensor is the source of spacetime curvature according to the Einstein field equation.

As to why the EFE is correct, like all fundamental physical principles that is simply postulated, and it is justified because it seems to fit the data well.
 
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Thank you all, you have been a huge help!
 
In my GR class, the Einstein field equation was motivated as some sort of 4-dimensional, relativistic analogue to the Poisson equation for Newtonian-gravity, which is equivalent to Newton's inverse square law.

So, no we don't know why mass curves space-time--it just does, but there were some initial observations, like special relativity, time dilation in a gravitational field, the equivalence principle, and a bunch of tensor calculus/differential geometry that helped Einstein (with some help from his mathematician friend, Marcel Grossmann) to figure that out that it does. Newton's law of gravity also needed to be fixed, just as the rest of Newton's laws needed to be fixed, due to special relativity.

Incidentally, if you want to get a better feel for why space-time curvature explains gravity, here's a good to read:

http://math.ucr.edu/home/baez/einstein/
 
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That's all neat I have much to learn until I can do the math and the physics but I'll bookmark the page. I read a little about the stress energy tensor to get better understanding but I am failing to understand where the energy comes from, is it just the energy of the mass and momentum that bends space-time?
 

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