Why are tests of general relativity based on vacuum solutions?

[Mentz114]

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.

 

[PeterDonis]

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.)

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.

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).

 

[PeterDonis]

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.