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Relativity FAQ

Sep10-12 10:09 AM bcrowell

Special & General Relativity

- Dependence of various physical phenomena on relative motion of the observer and the observed objects. Exp. & theo. theories of relativity
 Views: 8,597 Announcement: Two free ways to get Gold Membership! Jan17-12 Meta Thread / Thread Starter Last Post Replies Views Before posting anything, please review the Physics Forums Global Guidelines. If you are seeking help with a... Feb23-13 08:40 AM ZapperZ 1 36,678 The section of the Usenet Physics FAQ titled "Experimental Basis of Special Relativity" has been cited here many... Dec31-07 02:06 AM jtbell 0 36,538 Hi. I know that space for an object in motion will contract, relative to an observer. We generally read that space... Jan25-14 02:29 PM Mentz114 62 1,158 How do you find the inverse of metric tensor when there are off-diagonals? More specifivally, given the (Kerr)... Jan25-14 10:48 AM Nabigh R 4 250 With Δt = γ ( Δt' + v Δx' ) For calculating delta t for stationary twin with values of traveling twin. Is it... Jan25-14 12:35 AM morrobay 2 194 Tensors can be of type (n, m), denoting n covariant and m contravariant indicies. Rank is a concept that comes from... Jan24-14 09:50 PM jcsd 4 207 Hi, I'm trying to understand why the metric I've seen for AdS space,... Jan24-14 11:38 AM copernicus1 0 171 From what I learned watching Brian Greene's "Fabric of the Cosmos" episode on Nova, if you look at spacetime like a... Jan23-14 08:56 PM PeterDonis 3 253 This is about Hans Ohanian, "Einstein's E = mc2 mistakes," http://arxiv.org/abs/0805.1400 , a historical paper that... Jan23-14 06:03 PM bcrowell 0 186 I'm concerned about your book. I got up to this part: And I got very concerned. Although what you say is true,... Jan23-14 03:40 PM PhilDSP 28 690 If space-like Killing vectors are associated with a conserved momentum, and timelike Killing vectors are associated... Jan23-14 03:26 AM pervect 3 266 Hello all, I will preface this post with an apology for not putting it in the math/science learning materials... Jan22-14 06:58 PM bcrowell 6 288 There's an equation from Dirac's book on General Relativity that I don't get at all. It isn't derived; instead it's... Jan22-14 06:03 PM Bill_K 3 245 I've been working on a problem that I can't seem to get started on. Here is how it is posted: Metric of a space is:... Jan22-14 03:47 PM Libra82 13 353 Disclaimer: I have no formal education in physics. I watched a TedTalk... Jan22-14 02:58 PM mfb 1 199 A quick question I hope: What would I see from Earth if I sent a rocket to Saturn at nearly the speed of light? ... Jan22-14 02:42 PM DaleSpam 64 1,302 What happens to a particle in a scalar potential U(t,x)? I have been living under a belief that the equation of motion... Jan22-14 01:40 PM jostpuur 12 388 We are trying to find the relative velocity in a Lemaitre observer's frame, when said observer passes an observer... Jan22-14 05:06 AM Mentz114 15 383 After learning about special relativity, and the behavior of light, I do not understand why light is not able to reach... Jan21-14 05:36 PM stevmg 41 1,269 The full Lagrangian for electrodynamics ##\mathcal{L}## can be expressed as ##\mathcal{L}=\mathcal{L}_\textrm{field}+... Jan21-14 09:21 AM dextercioby 2 281 I've written an open-source book on special relativity: http://www.lightandmatter.com/sr/ . It's a work in progress,... Jan20-14 09:35 PM bcrowell 2 272 In the wikipedia page a distinction is made in the definition of the SR 4-acceleration between the case with... Jan20-14 03:32 PM TrickyDicky 4 298 I remember reading something, long ago, to the effect that any attempt at creating a CTC would be doomed by energy... Jan20-14 01:30 PM PAllen 4 296 If you don't have any charges or currents, the electromagnetic Lagrangian becomes... Jan20-14 12:33 PM BruceW 14 417 The Lagrangian for a point particle is just L=-m\sqrt{1-v^2}. If instead we had a continuous distribution of matter,... Jan20-14 11:16 AM dextercioby 10 392 I am just wondering - is space-time curvature in the presence of energy-momentum ( i.e. in interior solutions to the... Jan20-14 08:26 AM Markus Hanke 4 237 Two twins A and (evil) B. Twin A remains "stationary" while evil B goes at near light speed to-and-fro. Ignoring... Jan20-14 02:36 AM tom.stoer 10 379 Is there any reason to think that that the speed of light could vary with time (taking t=0 at Big Bang), ie, could... Jan19-14 03:27 PM stevmg 28 1,213 I want to ask General Relativity is a force or Its a theory which explains how to space-time curve and space-time... Jan19-14 02:37 PM A.T. 1 234 Hi, In his original paper, Schwarzschild set the "'equation of the determinant" to be: |g|=-1. In other words, he... Jan19-14 02:09 PM Rob Sfic 17 514 A satellite orbiting the globe at some 300 miles at 18000 mph. Does the clock on the GPS tick slower or faster than... Jan19-14 12:04 AM stevmg 2 240 If I start with the standard FRW cosmology equations, {\eqalign{ 3\dot a^2/a^2&=8\pi\rho-3k/a^2\cr 3\ddot... Jan18-14 11:23 PM stevmg 5 351 In the special relativity the conservation of energy and momentum is represented by the equation:... Jan18-14 07:02 PM WannabeNewton 21 696 Hi All, Long time no post! I've asked a highly-related question to the one I'm about to ask here, but there's a... Jan18-14 12:42 PM phyti 34 1,470 Ok folks, I've taken a stab at the Latex thing (for the first time, so please bear with me). I've mentioned before... Jan18-14 09:49 AM grzz 3 266 If I start with the stress-energy tensor T^{\mu\nu} of the electromagnetic field and then apply energy-momentum... Jan17-14 11:05 AM WannabeNewton 5 382 According to Wikipedia, This definition doesn't sit well with me. Flux is defined as the rate that something... Jan16-14 10:31 PM pervect 10 367 Here is a excellent book on special relativity and world lines. ... Jan16-14 08:56 PM arydberg 0 295 Length and distance in SR ( 1 2 3 ... Last) I would appreciate views on the following understanding of length and distance in SR, restricted here to inertial... Jan16-14 04:52 PM PAllen 73 2,235 If gravitational waves cause fluctuations in space time, than could all gravitational waves, large or small all would... Jan16-14 03:32 PM ilikescience94 0 226 So I've been reading Einstein's theory of relativity, and at one point when discussing the Lorentz equations' proof... Jan16-14 12:45 PM DaleSpam 3 246 Does \eta^{\alpha \beta}=\eta_{\alpha \beta} in all coordinate systems or just inertial coordinate systems? Jan16-14 11:43 AM dEdt 3 277