Testing SR with a Rotating Mass: Experiments & Theory

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Discussion Overview

The discussion revolves around the theoretical implications of testing special relativity (SR) with a rotating mass and its effects on gravitational fields and light. Participants explore the relationship between mass, energy, and gravity in the context of relativistic speeds, particularly focusing on how these factors might influence the bending of light from a high-frequency laser near a rotating mass.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested
  • Mathematical reasoning

Main Points Raised

  • One participant proposes an experiment involving a high-density mass rotating at relativistic speeds, suggesting that its increased mass due to SR would create a gravitational field capable of bending laser light.
  • The same participant presents a series of equations linking energy, mass, and gravitational force, implying that the gravitational effects on light could be measurable, albeit small.
  • Another participant questions the validity of using mass values for photons in the proposed equations, citing concerns about violating Lorentz invariance, which has been experimentally constrained.
  • A participant asks for clarification on the concept of Lorentz invariance, indicating a potential gap in understanding among participants.
  • One participant discusses the derivation of the Schwarzschild radius, suggesting that the energy of a photon can be treated as mass in gravitational equations.

Areas of Agreement / Disagreement

Participants express differing views on the treatment of mass in relation to photons and the implications for Lorentz invariance. There is no consensus on the validity of the initial proposal or the mathematical framework presented.

Contextual Notes

Some assumptions about the applicability of mass-energy equivalence to photons and the nature of gravitational fields are not fully resolved. The discussion includes unresolved mathematical steps and varying interpretations of relativistic effects.

Phymath
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What if someone set up an experiment, where they sped up a mass of high density in a circle ethier by making its radius smaller and smaller, until the large mass is moving near the speed of light, then at an extremely small highet above this rotating mass you set off a high frequency laser light, theorticly shouldn't the mass of the moving object increase, because of SR, thus having a larger gravitational field, and then the grav field should bend the laser light. It is most likely such a small divergence that it is unmeasureable but wouldn't we expect to see this? According to the force eqaution..

[tex]E = mc^2 = hf \ F = \frac{G m_1 m_2}{r^2}[/tex]
[tex]m = hf/c^2[/tex] the grav force is acting on the "mass" of the light
[tex]F = \frac{G m_1 hf}{r^2c^2} \ m' = \frac{m_0}{\sqrt{1 - \frac{v^2}{c^2}}}[/tex]
[tex]F(m_o,v,f,r) = \frac{Gh}{c^2} \frac{m_0}{\sqrt{1-\frac{v^2}{c^2}}} \frac{f}{r^2}[/tex]

which can of course broken into a relation of v to the rotational frequencey of the mass. Also as is my understanding that a grav field effects clocks, so that in this synethic grav field that anything moving through it would have its relative time slow down. ie see everyone else moving slower then they are.
 
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am I to assume that all of this seems sound? and that this Force should be expected
 
You cannot plug in a mass value for photons this way without breaking Lorentz invariance. Experimental tests have constrained Lorentz invariance violations to no more than one part in 10E20.
 
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what is Lorentz invariance?
 
i believe u find the Schwarzschild Radius by stating that the "mass" of a photon is hf/c^2 so that a grav field acts on anything with energy.

[tex]U = \frac{G m_1 m_2}{r} \ m_2 = \frac{hf}{c^2}[/tex]
[tex]\frac{1}{2} m v^2 = \frac{G m hf}{rc^2}[/tex]
[tex]\frac{hf}{c^2} v^2 = \frac{2 G m hf}{rc^2} \ v = c[/tex]
[tex]c^2 = \frac{2 G m}{r} \ r = \frac{2Gm}{c^2}[/tex] <- Schwarzschild Radius
 

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