Special & General Relativity

- Dependence of various physical phenomena on relative motion of the observer and the observed objects. Exp. & theo. theories of relativity
 Meta Thread / Thread Starter Last Post Replies Views Views: 5,661 Announcement: Follow us on social media and spread the word about PF! Jan16-12 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 42,429 Before posting anything, please review the Physics Forums Global Guidelines. If you are seeking help with a... Feb23-13 08:40 AM ZapperZ 1 42,791 I am doing a research about the compact Milne Universe in two dimensions Using special relativity. such that (t,θ)... Aug28-13 08:35 AM hazha 0 32 Definition of Large-Scale Isotropy and Homogeneity This post is part of my attempt to develop a formal definition... Aug23-14 11:23 PM andrewkirk 0 76 Consequences of Energy conservation in a FLRW spacetime This entry uses the local energy conservation law to derive... Aug23-14 10:39 PM andrewkirk 0 79 Corrections to Narlikar paper The paper by Jayant N Narlikar ’Spectral shifts in General Relativity’ in the... Aug23-14 11:04 PM andrewkirk 0 80 Einstein tensor in the FLRW frame - Part 1 of 2 This note develops a formula for the ##G^{00}## component of the... Aug23-14 10:48 PM andrewkirk 1 92 A quick question. It's been a long time since I had anything to do with special relativity, so I really can't... Y 01:45 PM ghwellsjr 1 95 Equations of state for photon gas and relativistic electron gas This entry develops equations of state that are... Aug23-14 11:28 PM andrewkirk 0 102 I've been reading Kip Thorne's "Black Holes and Time Warps," and it mentioned something rather counter-intuitive;... Y 06:16 PM MattRob 0 108 The Lorentz's transform: ##x' = k(x - vt), t' = k(t - vx)\ k = \gamma,\ and\ c = 1## I. The speed composition... Y 10:15 PM DaleSpam 3 120 I know that you're going to probably say that a frame of reference doesn't make sense for light, but I've uploaded a... Feb5-13 09:38 PM Drakkith 4 124 Is it possible to find the parametric representation X= x(y^{a}) of a surface given the components of the metric... Sep16-14 03:24 PM ChrisVer 0 124 In this paper: http://www.jstor.org/stable/25170907?seq=1 the authors claim to show that linearity of the lorentz... Sep17-14 08:07 AM center o bass 0 141 Is there gravity between two photons? Y 03:49 PM dextercioby 3 145 For another BRS thread, I looked up some information at http://www.genealogy.ams.org/ and was completely sidetracked... Mar1-10 05:00 PM Chris Hillman 2 146 Although I can't nominate myself for a Nobel Prize, I was wondering I any distinguished scientist would oppose such a... Feb12-13 02:55 AM kloptok 4 156 Draft re Ricci vs Riemann tensors This one is really just the beginning of a musing. I can't even remember if I... Aug28-14 02:54 AM Markus Hanke 1 161 I have some problems verifying a particular equation in the Cartan formalism of GR. Basically I want to prove the... Sep8-14 12:07 PM kurre 0 161 A train (source) approaching a stationery observer, wavelength of the sound is equal to the distance between source... Sep14-14 12:24 PM jtbell 2 161 The Friedmann equation states that $$(\frac{\dot a}{a}) = \frac{8\pi G}{3} \dot \rho + \frac{1}3 \Lambda -... Sep16-14 04:18 PM PeterDonis 5 167 According to SR, there is no measurement that can determine whether an object is stationary or under motion. So if two... Sep16-14 11:19 AM ghwellsjr 4 174 Blog entry by Bill_K The Absolute Derivative In relativity we typically deal with two types of quantities -... Sep2-14 11:00 PM Bill_K 0 174 I'll try rephrasing my question, as I do not wish to question the theory itself. Verily, verily, it would be... Feb16-13 04:19 PM Didymus 4 176 I've been starting to look at the Hilbert action derivation of Einstein's equations, and have an introductory... Sep14-14 12:34 PM Orodruin 1 182 Apriori -- before taking any of the postulates of special relativity into account -- we might say that the lorentz... Y 02:53 PM center o bass 4 183 I just recently derived the metric tensor of the 4-sphere by embedding the coordinate system within 5D spherical... Sep15-14 03:30 AM ChrisVer 5 186 We know how objects such as the metric tensor and the Cristoffel symbol have symmetry to them (which is why g12 = g21... Sep2-14 08:04 PM Matterwave 1 188 One argument against Mach's principle is the speed of light restriction. How could the distant cosmic mass of the... Y 02:37 PM stevendaryl 10 189 So let's say we have a neutron star. A neutron star is very massive and very dense therefore it has a very strong... Sep17-14 06:49 PM PAllen 5 190 This expression: \Gammaavc\Gammacab Can someone please show me how to multiply the two Christoffel symbol... Aug14-14 12:45 PM HallsofIvy 1 190 Blog Entry by Bill_K A spacetime is often described in terms of a tetrad field, that is, by giving a set of basis... Sep2-14 11:01 PM Bill_K 0 190 How can speed of light be absolute yet that fact and relativity of sublight speed implies relativity of space and time... Sep17-14 10:42 AM Nugatory 2 196 I am trying to expand$$\varepsilon^{{abcd}} R_{{abcd}} by using four identities of the Riemann curvature tensor: ... Sep17-14 06:41 AM ChrisVer 5 198 Here's a weird question where I don't quite know if length contraction or time dilation play a role. Say I have 2... Sep7-14 03:44 PM Nugatory 1 205 In this source explaining how to derive the Schwarzchild metric, the person came up with an ansatz and worked from... Aug21-14 08:31 AM Nugatory 1 208 I’ve just read Schutz: “Gravitation from ground up”. He says that there are 4 (not all independent) sources of... Sep12-14 08:09 AM jedishrfu 1 215 Alright, I'm rather new to General Relativity, and I'm getting confused with four momentum. Back in SR, p^α=mU^α, but,... Sep15-14 08:55 PM Dirac271 2 217 Dear all, I was reading this... Aug9-14 03:04 PM dextercioby 2 218 In my recent studies of curvature, I worked with the Riemann tensor and the equation: (\deltaV)a=... Sep9-14 06:02 PM pervect 2 227 When you have a general coordinate chart on spacetime you have a lot of freedom to pick your coordinates, but you are... Aug12-14 07:03 PM Fredrik 1 228 when muons are created in the atmosphere and fall to earth the earth clock runs faster. Thus, the "slower" muon clock... Aug4-14 10:08 PM PAllen 2 233