
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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42,032 
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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42,387 
Hi,
I am in the process of trying to teach myself GR Maths, at the A101 level, and have been working through the idea...

Dec810 09:01 AM
Mentz114

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1,392 
Silly proposition  but take the peculiar results predicted by Einstein in Part IV of the 1905 paper with a little...

Apr507 12:08 PM
pervect

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1,058 
Hello fellow physicsists!
I have some (and will probarbly get more) questions about differential geometry and...

Jun2512 09:15 AM
Muphrid

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1,159 
If we take a photon as our frame of reference is it safe to say that the universe moves relative to "Us" at the speed...

Aug2904 06:12 PM
Nenad

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3,439 
I have been reading GR but I have these gaps in understanding. Can someone help clear them?
1) SR has a...

May2014 09:55 PM
Matterwave

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588 
Hi, I have some questions about general relativity. I'd appreciate if somebody could enlighten me :)
I heard that...

Nov3012 02:18 PM
PeterDonis

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1,828 
I have some questions about time dilation I not really understand to come further (and I find it all very...

Dec811 09:19 PM
digi99

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2,678 
a)Can we add extra terms with covariant derivative equal to 0 so the coupling constant in relativity is...

Aug2904 07:18 AM
eljose79

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1,226 
Why do we say that the position 4vector, x^{\mu}, is naturally contravariant and that the del operator,...

Feb2706 06:43 PM
pmb_phy

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1,424 
I am not interested in knowing the detailed calculation but would be more than happy if you could just answer the...

Jul1709 05:00 AM
A.T.

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3,255 
2 random thoughts that struck me:
Q1. If an object is moving downwards towards a large mass at just under the speed...

Feb2410 03:31 PM
bcrowell

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892 
Hello PF,
I have some questions which I cant get an answer, and everything I think is based on intuition and not on...

Apr2509 08:35 AM
Dweirdo

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1,489 
A discussion with nakurusil left open some questions to which answers are highly appreciated.
1. We measure in...

Feb1507 03:38 AM
pmb_phy

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4,268 
Does " What you don't see with your eyes, don't invent with your mouth" does work in special relativity?:rofl:

Oct2310 05:13 PM
yuiop

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2,224 
I hope that a short discussion of the history of theoretical development is not too much offtopic here; this is a...

Feb1112 10:42 AM
harrylin

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3,270 
Hi, I have 2 little questions and hope to find some clarity here. It concerns some mathematics.
1) Is the variation...

May207 04:11 AM
haushofer

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3,381 
In the cosmology forum I have admitted to understanding GR only dimly despite, in a previous thread in this forum...

May207 07:25 PM
pervect

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3,168 
1. Does light(photons) have 0 mass or infinite?(b/c it its mass would be zero, it would take no energy to slow it...

Jan507 02:47 AM
anantchowdhary

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6,322 
Here are two statements of Birkhoff's theorem:
"Any spherically symmetric solution of the vacuum field equations...

Aug1210 05:22 PM
atyy

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913 
I don't think this should be a very difficult question for people who are used to working with tensors, but I'm new to...

Feb1311 02:01 PM
Fredrik

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1,846 
Hey,
Starting with the conversation law for the stressenergy tensor; T^{\alpha \beta}{}_{,\beta}=0 . Does anyone...

Oct2509 05:44 AM
haushofer

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1,177 
I've just started learning about special and general relativity and came up with a couple of questions that look like...

Oct113 03:25 PM
Serioza

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1,074 
1. A clock is placed on a light beam.
Will the clock stop?
If yes, why doesn't the beam stop altogether?
2....

Apr1210 11:02 AM
ZapperZ

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3,327 
Scenario 1:
A photon is travelling straight towards a star. As it goes deeper in the star's gravitational well, its...

May910 04:44 PM
espen180

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682 
I'm coming at this from the perspective of something that might be used in a general discussion piece on SR, or maybe...

Mar3106 04:16 PM
clj4

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1,201 
How can we visualize 4D spacetime and how gravity plays a role in 4D spacetime??

Jan2907 03:34 PM
Schrodinger's Dog

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1,065 
I think i understand that if my friend, let's call him bob  were to travel to the moon and back at near the speed of...

Oct1411 12:43 PM
phinds

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922 
The reason there are so many paradoxes is there is something fishy about Special Relativity (not General Rel) that no...

Oct2212 10:46 PM
jtbell

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Okay first of all, I know it's impossible to travel faster than light. But they say that IF.... IF you could, then you...

Feb113 01:33 PM
Fredrik

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2,493 
I am looking for help on page 128 equation (14) from zee's book Einstein Gravity.
A lot of you may not have the book....

Jul1813 09:58 AM
Bill_K

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452 
I have a little problem.. Just a little mind problem, that has bothered me for a while..
Lets say there is three...

Nov908 02:19 AM
Fredrik

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1,572 
If man were able to travel the speed of light  what would it sound like to this man? Would it be a mad deafening...

Aug1304 12:25 PM
turin

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1,776 
http://www.livescience.com/technology/070112_ftl_sound.html

Jan1707 05:28 PM
ZapperZ

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1,246 
Rindler (1977): Essential Relativity, 2nd ed., p. 249, deriving Maxwell's equations for orthonormal/inertial...

Nov2610 03:26 PM
DrGreg

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1,107 
Imagine a massless, classically zero curvature, infinite spacetime in which propagates a single actual photon. What...

Nov1504 07:40 AM
nitin

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1,484 
Is the local propagation of an entity at invariant speed a sufficient condition for its stressenergy tensor,...

Sep1812 07:23 PM
bcrowell

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904 
Is the following correct? In Newton's theory, gravity is a force (described in terms of a scalar potential field and...

Dec1710 11:09 AM
Mentz114

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2,337 
Ok , during my study , I read that the bodies which are rotating spherically symmetrically do not emit GW;s as in...

Dec2606 02:43 AM
pervect

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2,653 
hi
i heard once if you go out into space you get older faster than if you were on earth... any truth in this? if...

Feb606 01:11 PM
selfAdjoint

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Are space & time same ,like two sides of a coin , one cannot exist without another ? Also does time exist for photons ?

Jun2908 07:20 AM
ismaili

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1,201 