Faster Than Light?

Just to be provocative (in reality I agree with you that light cones are more fundamental objects than any spacelike hypersurface, and that light cone surfaces are physically meaningful at least in the local neighbourhood of p) I'll drop in some Bob Geroch: "[Special Relativity]…

raattgiftJul 25, 2022View on HNParent context

Neat, thank you for posting this. It is nicely organized, and while most HN readers would find §2 pretty steep, the content of §2.1.4 (Massless particles), §2.3.2 (Geodesics and affine parameters) and §2.3.4 (Massless particles and the Speed of Light) are concise technical…

raattgiftApr 26, 2022View on HNParent context

I hope this helps. In order to get anywhere close to "25" I will ignore some factors and engage in a bit of "lie to students" terminological and notational abuse. > ... may be helpful to discover an extension of the theory. The authors have a set of families of alternatives to…

raattgiftFeb 24, 2022View on HNParent context

Causality violations probably aren't really that much of a problem for mathematical physics. Geroch (a very well known and highly cited relativist) takes a shot at this in a short paper considering a "democracy of causal cones" rather than simply the one that matches light: "All…

raattgiftMar 5, 2021View on HNParent context

> what most people would consider to be fundamental Most people should then have it explained to them that frame-dependent quantities are not fundamental. This is something that arises even in their first exposure to Newtonian physics: kinetic energy is just such a…

raattgiftAug 14, 2018View on HNParent context

http://arxiv.org/abs/1005.1614

TheLoneWolflingJun 10, 2014View on HNParent context