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Thread: kinetic and potential energy vs. gravity in relativty

  1. #1 kinetic and potential energy vs. gravity in relativty 
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    According to relativity, does an object's kinetic energy contribute to its gravitational pull? What about gravitational potential energy?

    For example, if I have a system that consists of two masses some distance from each other, would the apparent gravity of the system increase if the two masses accelerate toward each other, converting their gravitational potential energy into kinetic energy?


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  3. #2  
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    Really? No one? I thought there were at least a few people who had seriously studied relativity here.


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  4. #3 Re: kinetic and potential energy vs. gravity in relativty 
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    Quote Originally Posted by Scifor Refugee
    According to relativity, does an object's kinetic energy contribute to its gravitational pull? What about gravitational potential energy?

    For example, if I have a system that consists of two masses some distance from each other, would the apparent gravity of the system increase if the two masses accelerate toward each other, converting their gravitational potential energy into kinetic energy?
    The stress-energy tensor of general relativity determines the curvature which is what produces what we call gravity. That tensor is independent of the reference frame used. So yes, the relativistic mass is one element that determines the tensor in a particular system, but there are other factors which compensate for the mass increase and the curvature remains independent of the motion of the object as reflected in any choice of reference frame.

    And yes, gravity gravitates.
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  5. #4 huh 
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    space time cannot be curved.and i am ademant, that einstein.just brushed up his theory to suit whoever he wanted to...
    BANKAI........
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  6. #5 Re: huh 
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    Quote Originally Posted by pep_i
    space time cannot be curved.and i am ademant, that einstein.just brushed up his theory to suit whoever he wanted to...
    You are a damn what ? Ant? Nope, insects are more perspicacious.

    Space-time is most certainly curved. Einstein formulated a theory of gravitation that is not only elegant, but also that predicts very subtle effects that have been confirmed by some exquisitely sophisticated experiments.

    In short, you don't know what you are talking about.
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  7. #6 Re: huh 
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    Quote Originally Posted by DrRocket
    Quote Originally Posted by pep_i
    space time cannot be curved.and i am ademant, that einstein.just brushed up his theory to suit whoever he wanted to...
    You are a damn what ? Ant? Nope, insects are more perspicacious.

    Space-time is most certainly curved. Einstein formulated a theory of gravitation that is not only elegant, but also that predicts very subtle effects that have been confirmed by some exquisitely sophisticated experiments.

    In short, you don't know what you are talking about.
    It's just a frustrating twist of terminology. First, you have to think in 4 dimensions instead of 3 in order to understand it, and then you're never quite sure you're seeing what you're meant to see or not.

    However, the mathematical description is somewhat more clear. Unfortunately, you can't just spew equations at the uninitiated, so saying "Space Time is curved" might be the best description that's possible. .... sadly.

    I personally like to hope that there's a simpler math that could describe all the same events in the same detail, and end up being accurate (perhaps with the added bonus of not needing "Dark Matter" in order to bear out on the larger scales). Unfortunately, I don't know quite what that simpler math would look like, so GR will have to do for now.
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  8. #7 Re: huh 
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    Quote Originally Posted by pep_i
    space time cannot be curved.and i am ademant, that einstein.just brushed up his theory to suit whoever he wanted to...
    I fully agree, plus Einstein was a plagiarist anyway so in that way he shouldnt be trusted either. Dr Rocket, Space-time curvature as an explaination for gravity or anything for that matter is certainly not elegant, its an absurdity. I dont know how you can gain a sense of "scientiffic satisfaction" through that theory, its just terrible and is far away from reality.
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  9. #8 Re: huh 
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    Quote Originally Posted by Waveman28
    Quote Originally Posted by pep_i
    space time cannot be curved.and i am ademant, that einstein.just brushed up his theory to suit whoever he wanted to...
    I fully agree, plus Einstein was a plagiarist anyway so in that way he shouldnt be trusted either. Dr Rocket, Space-time curvature as an explaination for gravity or anything for that matter is certainly not elegant, its an absurdity. I dont know how you can gain a sense of "scientiffic satisfaction" through that theory, its just terrible and is far away from reality.
    The only thing far from reality is your estimates of your own competency.
    Disclaimer: I do not declare myself to be an expert on ANY subject. If I state something as fact that is obviously wrong, please don't hesitate to correct me. I welcome such corrections in an attempt to be as truthful and accurate as possible.

    "Gullibility kills" - Carl Sagan
    "All people know the same truth. Our lives consist of how we chose to distort it." - Harry Block
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  10. #9 Re: huh 
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    Quote Originally Posted by Waveman28
    Quote Originally Posted by pep_i
    space time cannot be curved.and i am ademant, that einstein.just brushed up his theory to suit whoever he wanted to...
    I fully agree, plus Einstein was a plagiarist anyway so in that way he shouldnt be trusted either. Dr Rocket, Space-time curvature as an explaination for gravity or anything for that matter is certainly not elegant, its an absurdity. I dont know how you can gain a sense of "scientiffic satisfaction" through that theory, its just terrible and is far away from reality
    Yep. I agree. You don't know.

    That iincreases by 1 the huge number of things that you don't know.

    What is even more impressive is the equally huge number of things that you do know, that are in fact false.
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  11. #10 Re: huh 
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    Quote Originally Posted by KALSTER
    Quote Originally Posted by Waveman28
    Quote Originally Posted by pep_i
    space time cannot be curved.and i am ademant, that einstein.just brushed up his theory to suit whoever he wanted to...
    I fully agree, plus Einstein was a plagiarist anyway so in that way he shouldnt be trusted either. Dr Rocket, Space-time curvature as an explaination for gravity or anything for that matter is certainly not elegant, its an absurdity. I dont know how you can gain a sense of "scientiffic satisfaction" through that theory, its just terrible and is far away from reality.
    The only thing far from reality is your estimates of your own competency.
    Ah come on, even you once confessed that the aether may exist, which in turn could provide much more logical explainations of the phenomena in reality. Just to clarify things with you and Dr Rocket, im not some fool that gets a kick out of posting empty comments about how everything the scientific community thinks it knows is wrong. I cant stand the theories conjured up by people with topics such as FTL, teleporting, and other absurd things, because there just a waste of time. However im giving constructive criticism of theories that also fall into the "absurdity" category, which special and general relativity amoungst other accepted theories definitely fall into. I never refute or dispute theories such as thermodynamics, classic mechanics etc. because they are based on logical foundations and dont contain any abstract personal creations such as the delerious "space-time" idea, which youve got to addmitt is pretty horrid. I ammit that relativity is obviously a true fact, the equations perfectly show what happens when observers observe relative events, but i strongly doubt that the physical cause for this phenomena is what this theory says it is. And cause and effect are at the heart of undersatnding reality.
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  12. #11  
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    Ah come on, even you once confessed that the aether may exist
    Yeah, but those are my flights of fancy. I don't have delusions that I fully understand current theory to the T and neither should you. It is fun to speculate, but you and I really know jack.
    Disclaimer: I do not declare myself to be an expert on ANY subject. If I state something as fact that is obviously wrong, please don't hesitate to correct me. I welcome such corrections in an attempt to be as truthful and accurate as possible.

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  13. #12  
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    Well, waveman, I am just all ears to find out the alternate explanation for how spacetime doesn't go and get bent, beyond an emotional appeal that it 'doesn't feel right'.

    Maybe you can explain the 'flaws' in the observational experiments confirming spacetime going on a bender?
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  14. #13  
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    "Maybe you can explain the 'flaws' in the observational experiments confirming spacetime going on a bender"....in the New Hypothesis section.
    Disclaimer: I do not declare myself to be an expert on ANY subject. If I state something as fact that is obviously wrong, please don't hesitate to correct me. I welcome such corrections in an attempt to be as truthful and accurate as possible.

    "Gullibility kills" - Carl Sagan
    "All people know the same truth. Our lives consist of how we chose to distort it." - Harry Block
    "It is the mark of an educated mind to be able to entertain a thought without accepting it." - Aristotle
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  15. #14 Re: kinetic and potential energy vs. gravity in relativty 
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    Quote Originally Posted by Scifor Refugee
    According to relativity, does an object's kinetic energy contribute to its gravitational pull? What about gravitational potential energy?

    For example, if I have a system that consists of two masses some distance from each other, would the apparent gravity of the system increase if the two masses accelerate toward each other, converting their gravitational potential energy into kinetic energy?
    Kinetic energy is supposed to contribute towards inertial mass, whence gravitational mass as well, according to the Principle of Equivalence.

    About a year and a half ago (April 2008) I had posed the same question by e - mail to Clifford Will, author of "Was Einstein right?" and a world expert on experimental verification of Relativity. Here is wat I had written to him:

    "Dear Professor Will:

    I would like to ask the following question:

    Beams of particles have been accelerated, in CERN and elsewhere, to speeds comparable to that of light. This, for all I know, results in an increase in their inertila properties.

    Have such beams of particles ever been observed to curve as well, as a result of an equal increase in their gravitational properties, according to the Principle of Equivalence?"


    His reply was this:

    "There is an effect on the gravitational field produced by a relativistically moving particle, however it is not as simple as you would infer from the special relativistic increase in energy. People have worked out the details and considered possible experiments, but they concluded that the effects in high-energy accelerators would be too small to be detectable. Their motion in the Earth's gravitational field would also be affected by their relativistic speed, but again the effects are too small to be detectable."

    As for gravitational potential energy, it is assumed that ANY form of potential energy (electromagnetic, nuclear, etc.) results in inertial and gravitational mass. Hence, the various potential energies present in the atoms are thought to contribute to gravitational properties of matter, as well as inertial ones, equaly. It is speculated that the energy implied by the famous formula of Special Relativity: is precisely due to the various potential energies of the interractions between particles forming the nuclei (protons, neutrons) as well as between quarks forming these particles.

    Whether or not the gravitational potential energy contributes to gravitational and inertial mass equally, is under experimental check. It is speculated that if there was no gravitational contribution on the part of this energy, or if this contribution was not equal to the contribution in inertial mass, then bodies of different composition would exhibit different gravitaional properties (divergence from the Principle of Equivalence) which is not the case up to the current accuracy of experimental methods (.) Besides, if inertial and gravitatonal mass due to gravitational potential energy were not equal, then the Moon would "fall" in the Sun's gravitational field with different acceleration than Earth, which would result in the Moon's orbit being "elongated" towards the Sun. This has not been observed (the technique relies on lazer beams reflected upon panels placed on the Moon by the Apollo missions, as well as one on the Soviet vehicle Lunokhod). Nevertheless, much higher accuracy is expected to be achieved with experiments employing satelites ("MICROSCOPE", "STEP", "GALILEO GALILEI").
    Last edited by Obelix; January 3rd, 2012 at 08:36 PM.
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  16. #15  
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    Quote Originally Posted by C_Sensei
    Well, waveman, I am just all ears to find out the alternate explanation for how spacetime doesn't go and get bent, beyond an emotional appeal that it 'doesn't feel right'.

    Maybe you can explain the 'flaws' in the observational experiments confirming spacetime going on a bender?
    What experiments confirmed that space-time is curved? You will probably say stuff like the lights rays bending around the moon or something in a total solar eclipse, but what else have you got, because I can bet a more rational explaination will always be possible that does not involve the bending of space-time.
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  17. #16  
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    Please provide a "more rational" explanation then. In the meantime, I imagine DrRocket or someone can provide examples beyond the bending of light by everything with a gravitational pull.
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