
The section of the Usenet Physics FAQ titled "Experimental Basis of Special Relativity" has been cited here many...

Dec3107 02:06 AM
jtbell

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42,429 
Before posting anything, please review the Physics Forums Global Guidelines.
If you are seeking help with a...

Feb2313 08:40 AM
ZapperZ

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42,791 
I am doing a research about the compact Milne Universe in two dimensions Using special relativity.
such that (t,θ)...

Aug2813 08:35 AM
hazha

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32 
Definition of LargeScale Isotropy and Homogeneity
This post is part of my attempt to develop a formal definition...

Aug2314 11:23 PM
andrewkirk

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Consequences of Energy conservation in a FLRW spacetime
This entry uses the local energy conservation law to derive...

Aug2314 10:39 PM
andrewkirk

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Corrections to Narlikar paper
The paper by Jayant N Narlikar ’Spectral shifts
in General Relativity’ in the...

Aug2314 11:04 PM
andrewkirk

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80 
Einstein tensor in the FLRW frame  Part 1 of 2
This note develops a formula for the ##G^{00}## component of the...

Aug2314 10:48 PM
andrewkirk

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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

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Equations of state for photon gas and relativistic electron gas
This entry develops equations of state that are...

Aug2314 11:28 PM
andrewkirk

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I've been reading Kip Thorne's "Black Holes and Time Warps," and it mentioned something rather counterintuitive;...

Y 06:16 PM
MattRob

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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

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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...

Feb513 09:38 PM
Drakkith

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Is it possible to find the parametric representation X= x(y^{a}) of a surface given the components of the metric...

Sep1614 03:24 PM
ChrisVer

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In this paper: http://www.jstor.org/stable/25170907?seq=1 the authors claim to show that linearity of the lorentz...

Sep1714 08:07 AM
center o bass

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141 
Is there gravity between two photons?

Y 03:49 PM
dextercioby

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145 
For another BRS thread, I looked up some information at http://www.genealogy.ams.org/ and was completely sidetracked...

Mar110 05:00 PM
Chris Hillman

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146 
Although I can't nominate myself for a Nobel Prize, I was wondering I any distinguished scientist would oppose such a...

Feb1213 02:55 AM
kloptok

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Draft re Ricci vs Riemann tensors
This one is really just the beginning of a musing. I can't even remember if I...

Aug2814 02:54 AM
Markus Hanke

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I have some problems verifying a particular equation in the Cartan formalism of GR. Basically I want to prove the...

Sep814 12:07 PM
kurre

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161 
A train (source) approaching a stationery observer, wavelength of the sound is equal to the distance between source...

Sep1414 12:24 PM
jtbell

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161 
The Friedmann equation states that
$$(\frac{\dot a}{a}) = \frac{8\pi G}{3} \dot \rho + \frac{1}3 \Lambda ...

Sep1614 04:18 PM
PeterDonis

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167 
According to SR, there is no measurement that can determine whether an object is stationary or under motion. So if two...

Sep1614 11:19 AM
ghwellsjr

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174 
Blog entry by Bill_K
The Absolute Derivative
In relativity we typically deal with two types of quantities ...

Sep214 11:00 PM
Bill_K

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174 
I'll try rephrasing my question, as I do not wish to question the theory itself. Verily, verily, it would be...

Feb1613 04:19 PM
Didymus

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176 
I've been starting to look at the Hilbert action derivation of Einstein's equations, and have an introductory...

Sep1414 12:34 PM
Orodruin

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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

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I just recently derived the metric tensor of the 4sphere by embedding the coordinate system within 5D spherical...

Sep1514 03:30 AM
ChrisVer

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186 
We know how objects such as the metric tensor and the Cristoffel symbol have symmetry to them (which is why g12 = g21...

Sep214 08:04 PM
Matterwave

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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

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So let's say we have a neutron star. A neutron star is very massive and very dense therefore it has a very strong...

Sep1714 06:49 PM
PAllen

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This expression:
\Gammaavc\Gammacab
Can someone please show me how to multiply the two Christoffel symbol...

Aug1414 12:45 PM
HallsofIvy

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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...

Sep214 11:01 PM
Bill_K

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190 
How can speed of light be absolute yet that fact and relativity of sublight speed implies relativity of space and time...

Sep1714 10:42 AM
Nugatory

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I am trying to expand $$\varepsilon^{{abcd}} R_{{abcd}}$$ by using four identities of the Riemann curvature tensor:
...

Sep1714 06:41 AM
ChrisVer

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Here's a weird question where I don't quite know if length contraction or time dilation play a role.
Say I have 2...

Sep714 03:44 PM
Nugatory

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In this source explaining how to derive the Schwarzchild metric, the person came up with an ansatz and worked from...

Aug2114 08:31 AM
Nugatory

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I’ve just read Schutz: “Gravitation from ground up”. He says that there are 4 (not all independent) sources of...

Sep1214 08:09 AM
jedishrfu

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Alright, I'm rather new to General Relativity, and I'm getting confused with four momentum. Back in SR, p^α=mU^α, but,...

Sep1514 08:55 PM
Dirac271

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Dear all,
I was reading this...

Aug914 03:04 PM
dextercioby

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In my recent studies of curvature, I worked with the Riemann tensor and the equation:
(\deltaV)a=...

Sep914 06:02 PM
pervect

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When you have a general coordinate chart on spacetime you have a lot of freedom to pick your coordinates, but you are...

Aug1214 07:03 PM
Fredrik

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when muons are created in the atmosphere and fall to earth the earth clock runs faster. Thus, the "slower" muon clock...

Aug414 10:08 PM
PAllen

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