Note on Varying Speed of Light Cosmologies · HackerPapers discussions

Note on Varying Speed of Light Cosmologies — mentioned by raattgift

Wed, 20 Jul 2022 20:02:25 GMT

1/2 tl;dr: coincident-events first, then labels (coordinates). [Einstein 1916, p.117 [2] although I remembered to look there only after writing all of the below]. One-way speed of light arguments are in danger of being coordinates-first, and thus insufficiently general for physics.[3] The key word in your comment is > directly But why do we care? We have an abundance of indirect evidence, premised on direct tests of coordinate-independent features of our best most-fundamental theory. The two important features of (general) relativity are pointwise local Lorentz covariance -- where c is the…

Paper and discussion history. A mention is not an endorsement.

Note on Varying Speed of Light Cosmologies — mentioned by raattgift

Sun, 27 Aug 2017 02:48:08 GMT

Let's flip the question and ask what happens if we let the value of c depend on the location in spacetime. Ellis provides a "short checklist of issues that should be satisfactorily handled by" theories that have a value of c that depends on location in spacetime. https://arxiv.org/abs/astro-ph/0703751 The tl;dr version is that relativistic physical theories will need revising because in the face of a location-dependent c, and in particular the problem arises because we necessarily break lengths and durations when c is not everywhere-and-everywhen identical. More narrowly observables like…

Paper and discussion history. A mention is not an endorsement.