Tests of EFE: Assessing General Relativity's Validity Beyond Cosmology

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Discussion Overview

The discussion centers on the validity of the Einstein Field Equations (EFE) beyond cosmological contexts, particularly questioning the robustness of tests based on vacuum solutions. Participants explore whether there are experimental tests of the EFE that do not rely on the assumption of a vacuum and seek explanations for the equality of the left and right sides of the equations.

Discussion Character

  • Debate/contested
  • Technical explanation
  • Conceptual clarification

Main Points Raised

  • Some participants express concern that tests of general relativity, such as gravitational redshift and perihelion precession, are based on vacuum solutions of the EFE, leading to the conclusion that 0 = 0 does not adequately validate the equations.
  • Others argue that vacuum solutions can still possess non-trivial characteristics, such as non-zero Weyl curvature, which may provide meaningful insights into the field.
  • There is a discussion about whether the EFE can be expressed solely in terms of Weyl tensors, with some participants questioning the implications of simplifying the equations to 0 = 0.
  • Some participants assert that the Schwarzschild metric satisfies all experimental tests, while others challenge the notion that this proves the EFE's validity, emphasizing the need for non-vacuum solutions.
  • One participant highlights that geodesic motion is derived from the presence of matter, suggesting that tests of the EFE are not purely based on vacuum solutions.
  • Concerns are raised about the implications of assuming the right side of the EFE must equal zero, with some participants arguing that this does not prove the hypothesis of the EFE.

Areas of Agreement / Disagreement

Participants generally disagree on the implications of vacuum solutions and the validity of the EFE based on tests that yield 0 = 0. There is no consensus on whether there are sufficient experimental tests of the EFE that do not assume a vacuum.

Contextual Notes

Some participants mention the complexity of deriving the Schwarzschild solution and the assumptions involved in geodesic motion, indicating that the discussion may be limited by varying interpretations of the EFE and its applications.

  • #31
Vanadium 50 said:
In the words of Monty Python, "That's not argument! It's just contradiction!"
No it isn't !

It looks like we have a crackpot so this thread is doomed. Phew.
 
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  • #32
CycoFin said:
These are tests of very specific form of EFE where we have RHS zero tensor.

You're shifting your ground. Before, you were saying vacuum tests weren't tests of the EFE at all. Now you're saying they're tests, just tests of "a very specific form" of the EFE. (See below for more on that.)

CycoFin said:
We cannot use these test results to make any claim about general EFE

By this argument, you can't use any test results to make a claim about the general EFE, only about the "specific form" that you tested. You do realize that saying the RHS of the EFE is not zero does not pin down one specific "value" for the RHS, right? The RHS is the stress-energy tensor; there are many, many different forms that that tensor can take, depending on what kinds of matter and energy are present. Any test of the EFE is only going to test one "specific form" of the stress-energy tensor, corresponding to the particular kinds of matter and energy that are present during the test. A vacuum (no matter or energy present at all) is just one particular case among many.

CycoFin said:
I leaved cosmology out because problems we have there

So what? Cosmology still gives tests of the EFE, using the particular kinds of matter and energy present, on average, in the universe. And GR passes those tests for a large portion of the universe's history (basically back to times early enough that we're not sure what stress-energy tensor to use).
 
  • #33
CycoFin said:
I have some ideas how to tackle those if we accept only the vacuum EFE and dispose the general EFE

You appear to have basic misunderstandings about how the EFE is tested in the first place. We've done our best to address them in this thread, but I don't think there's much point in further discussion. This thread is closed.
 

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