# 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: 74,405 Announcement: Follow us on social media and spread the word about PF! Jan16-12 Before posting anything, please review the Physics Forums Global Guidelines. If you are seeking help with a... Feb23-13 08:40 AM ZapperZ 1 40,585 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 40,240 Bit confused regarding how non-inertial frames can be treated in GR (and by non-inertial i mean affected by some kind... Feb28-14 01:58 AM WannabeNewton 1 287 I am trying to write the Einstein field equations $$R_{\mu\nu}-\frac{1}{2}g_{\mu\nu} R=\frac{8\pi G}{c^4}T_{\mu\nu}$$... Feb27-14 10:56 PM Nabigh R 2 462 There is a moving light clock at a certain velocity. For an outside observer, the light just seemed to be traveling in... Feb27-14 07:04 PM DaleSpam 28 1,052 If we consider a perfect relativistic fluid it has energy momentum tensor T^{\mu \nu} = (\rho + p) U^\mu U^\nu +... Feb27-14 05:53 PM TrickyDicky 15 471 The solution of Einstein's field equations for a simple black hole show a slowing of time as you get close to the... Feb27-14 11:44 AM PAllen 37 2,033 Hi guys, Firstly apologies if this question has been asked before (or are stupid questions) or better explained... Feb27-14 08:58 AM jtbell 5 558 This is a purely terminological question. Consider the following setup: we have two inertial observers A and B at rest... Feb26-14 04:28 PM bcrowell 14 956 Hello To demonstrate that we can deduce from special relativity the existence of an observer who finds that his... Feb26-14 01:26 PM DaleSpam 54 2,119 I recently watched a video in Einstein's train though experiment. www.youtube.com/watch?v=wteiuxyqtoM From what... Feb26-14 11:29 AM Yashbhatt 17 719 Suppose we have an event horizon H which is a light-like, closed 2-surface. Photons radiated outwards at the horizon... Feb25-14 09:41 PM George Jones 3 339 Trying to understand the conservation of relativistic momentum, I thought of this problem. It's very simple, and... Feb25-14 03:55 PM epovo 2 286 I was just reading the sci.physics.faq http://math.ucr.edu/home/baez/physics/Relativity/SR/rigid_disk.html on the... Feb25-14 02:46 PM bcrowell 15 491 Hi all, I tried searching for this but failed to find an answer to my question. I am having an issue with properly... Feb25-14 01:01 PM scinoob 12 793 Howdy, This is my first post. Please be gentle. ;-) I have been thinking about the speed of light. Scenario... Feb25-14 09:19 AM dauto 4 447 Sorry I'm new to this. There are apparently four forces in the universe: Gravity, EM, Weak and Strong. Is gravity... Feb24-14 04:19 PM pervect 7 628 hi guys i have question can any body answer please. why the light fell in to the black hole whether it have no mass. Feb24-14 02:43 AM mra20x 3 332 Could spacetime itself be a field? Feb24-14 12:01 AM Fredrik 5 322 i have asked my physics and maths teacher a question which they could not answer, the question follows:- Does the... Feb23-14 06:30 PM pervect 15 775 I'm working through A. Zee's new EGR book, and I came to a step on tidal forces I couldn't follow. He presents the... Feb23-14 10:33 AM russelljbarry15 4 522 Is there an absolute sequence of events in the universe- independent of observation? It seems like so much emphasis is... Feb23-14 03:08 AM adrian_m 6 674 In the spirit of this forum I should first announce: -generally, I have no idea what I'm talking about but look for... Feb23-14 12:29 AM ghwellsjr 6 488 In Special Relativity the example is given of a pole that alternates color, as seen in its own rest frame. Someone in... Feb22-14 09:56 PM gabeeisenstei 19 696 Before I get down to business, I would like to note (you don't have to read this; feel free to skip to where it says... Feb22-14 06:31 PM pervect 2 313 Is it true that the speed of light is a conversion factor between time and space? and that D = C*T? and if it... Feb22-14 05:51 PM FactChecker 8 562 When we way that \frac{d^3p}{p_0}=\frac{d^3p}{\sqrt{m^2+\vec{p}^2}} is the invariant volume element, is that... Feb21-14 10:36 PM pellman 2 364 I am currently studying special relativity on my own and I am looking into space time and space time diagrams. While... Feb21-14 07:31 PM PeterDonis 5 398 In another thread we determined that the proper total force acting on an orbiting object in the Schwarzschild metric,... Feb21-14 09:11 AM Mentz114 5 416 Dumb question....but thought I'd throw it out there. So, ever since I was a little kid of 6 or so, I loved to look... Feb21-14 08:55 AM phinds 13 545 This is a very basic question, but I cannot get my head around the following: Any physical system should be invariant... Feb20-14 02:22 PM PAllen 34 1,209 Let's imagine a rocket orbiting the earth. The rocket could be any real rocket with moderate speed, so that... Feb19-14 07:51 PM PAllen 11 628 I was reading some posts on one of my previous threads (great discussion there btw) and I red something that I really... Feb19-14 06:20 PM WannabeNewton 23 1,013 I've been watching the Stanford lectures on GR by Leonard Susskind and according to him the metric tensor is not... Feb19-14 02:08 PM Chestermiller 9 718 Redshifting Through Hole in Earth ( 1 2 3 ... Last) I have been wondering what to expect if there was a hole, from pole to pole, that inside which we could measure the... Feb19-14 12:16 PM PeterDonis 88 2,649 When I studied special relativity for the first time, I encountered the exemple of a infinite neutral wire in the... Feb18-14 09:18 PM jartsa 8 720 On page 161 of Carroll's Spacetime and Geometry, Carroll writes that \delta... Feb18-14 03:32 PM Bill_K 9 417 We all know that the energy-momentum tensor for dust is just ##T^{\alpha\beta}=\rho_0 v^\alpha v^\beta##, where... Feb18-14 02:57 PM dEdt 0 292 I am currently taking an undergraduate modern physics course that offers a brief overview of relativity. Let us... Feb18-14 07:49 AM Chestermiller 12 568 It is said that Relativity proves that if one travels near the speed of light that time slows down, i.e. that the twin... Feb18-14 05:38 AM DaleSpam 2 348 Let's say there's a wormhole entrance on the floor of my room, and the exit would be on the ceiling. If I drop a ball... Feb17-14 11:17 PM HarryRool 9 520 If light approaches a black hole will it accelerate? I think this question ties in with whether light has mass or not.... Feb17-14 10:30 PM A.T. 10 529