Faster Than Light? · HackerPapers discussions

Faster Than Light? — HN submission

Thu, 06 Jun 2024 07:33:01 GMT

Faster Than Light? (2010) [pdf]

1 point; 0 discussion replies on HN. Paper and source history. A submission is not an endorsement.

Faster Than Light? — mentioned by raattgift

Mon, 25 Jul 2022 00:52:27 GMT

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] emerges as just one more physical system. It consists, just like the others, of certain fields subject to a certain system of first-order, quasilinear partial differential equations. The causal cones of special relativity (which reflect the speed of light) have no special significant over the causal cones of any of…

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

Faster Than Light? — mentioned by raattgift

Tue, 26 Apr 2022 02:29:06 GMT

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 answers to a HN FAQ which is essentially "according to relativity, do photons experience no time?". Really frequently "asked". (tl;dr answer: yes, they certainly do, you just write their "time" down differently from that of massive particles. The difference in their time ("affine time") tells you observable things -- for…

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

Faster Than Light? — mentioned by raattgift

Thu, 24 Feb 2022 08:03:15 GMT

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 General Relativity, and are exploring whether they are viable as a physical description of gravitation in our universe, and if not (spoiler: they're not; they admit this up front) whether any of them can be adapted into a good physical description. The second author of the (purely theoretical) headline paper in…

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

Faster Than Light? — mentioned by raattgift

Fri, 05 Mar 2021 16:50:02 GMT

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 systems, and their cones, are on an equal footing: No one set of fields, or one set of causal cones, has priority over any others." Geroch's argument is that one can still do initial-value-formulation physics even in the presence of causal cones whose width is different -- including wider -- than that of light.…

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

Faster Than Light? — mentioned by raattgift

Tue, 14 Aug 2018 11:55:19 GMT

> 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 frame-dependent quantity. Generally covariant and invariant quantities are candidates for fundamental quantities. The stress-energy tensor is, for example, generally covariant. However, one tends to want to slice it up into energy, pressure, stress, and so forth, and the fluxes of those in various directions. Those "sliced"…

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

Faster Than Light? — mentioned by TheLoneWolfling

Tue, 10 Jun 2014 14:16:52 GMT

http://arxiv.org/abs/1005.1614

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