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Feb2313 08:40 AM
ZapperZ

1 
37,495 
The section of the Usenet Physics FAQ titled "Experimental Basis of Special Relativity" has been cited here many...

Dec3107 02:06 AM
jtbell

0 
37,231 
In trying to understand relativity, I once read a statement that even travelling at the speed of light, an emitted...

Aug1513 07:23 PM
pervect

13 
794 
There is a closed thread c squared = e/m. I am piggybacking off of that discussion. c is a constant, and thus so is c...

Aug1513 03:14 PM
prasa043

2 
465 
Mod note: Posts split off from http://www.physicsforums.com/showthread.php?p=4468795
Hi, WN, might the OP be...

Aug1513 03:09 PM
PeterDonis

150 
3,388 
I was working on an exercise in Ohanian's book.
I guess he means charge conservation, but wrote ##j^\nu =...

Aug1513 02:50 PM
WannabeNewton

15 
595 
I was laying in bed and a thought came to me. Im sure this has been explored already so I wanted to know what the...

Aug1513 01:03 PM
HallsofIvy

61 
7,405 
I struggled long and hard to resist the idea that Alice observes nothing special as she falls into the Schwarzschild...

Aug1513 10:19 AM
PeterDonis

3 
451 
Hello all, so lets suppose a photon is being gravitationally red or blue shifted changing its frequency which...

Aug1513 07:11 AM
deadscientist

3 
398 
What is

Aug1513 01:46 AM
micromass

1 
353 
Hi!
I am really bad at physics so bear with me...
I saw some very interesting 3 hour physicsmarathon on TV the...

Aug1413 07:37 PM
rogerk8

41 
2,047 
If I were to hold a tennis ball out at arm's length, and release it, we all know it would fall due to gravitational...

Aug1413 07:34 PM
LuckyNate

6 
531 
On page 56 of "Theory of Spinors", Eq. (3.84a), Carmeli gives the formula for the Lorentz matrix in terms of Pauli...

Aug1413 02:37 PM
arkajad

80 
3,628 
Hi guys & girls,
I have a question regarding travelling faster than the speed of light, a small theory, which I am...

Aug1413 01:48 PM
mfb

14 
631 
Hello,
I recently read about a photon's point of view according to relativity(which is a fascinating thing for a high...

Aug1413 03:38 AM
BruceW

38 
2,490 
When media reports a supernova it sounds like it happened just a while ago despite the photon stream came from say 10...

Aug1413 01:52 AM
Romulo Binuya

8 
564 
\partialμ\phi\partialμ\phi
and
\partialμ\partialμ\phi
with \phi(x) a scalar field

Aug1313 04:59 PM
Mentz114

6 
492 
I want to be able to formulate x^{n} coordinate system.
x^{n} =(x^{1}, x^{2}, x^{3}, x^{4})
How do you do this when...

Aug1313 10:18 AM
ProfDawgstein

1 
354 
In order to understand how related are the theories of General Relativity and Electromagnetism, I am looking at the...

Aug1313 09:27 AM
nix00

7 
664 
Hello PF:
I noticed a thread on PF in which TOM STOER and others were discussing how to calculate the redshift...

Aug1313 06:26 AM
Mentz114

12 
241 
Hi,
Does the magnitude of the force change when the frame moves with a high speed with respect to another frame at...

Aug1313 02:47 AM
harrylin

6 
550 
Is the Milky Way Galaxy nonrotating or rotating?
Which metric is best suited: Schwarzschild or the Kerr Metric,...

Aug1213 11:57 PM
Mentz114

7 
429 
We sit in a room. I see you and you see me. We both understand we are seeing each other as we "were" a small time...

Aug1213 04:35 PM
DaleSpam

35 
2,187 
When I first learnt time dilation I was given this equation proven using the light clock example.
t = γt'
...

Aug1213 03:34 PM
ghwellsjr

34 
1,686 
The geodesic equation follows from vanishing variation ##\delta S = 0## with
##S = \int_C ds = \int_a^b dt...

Aug1213 08:20 AM
tom.stoer

2 
400 
How could you tell in an experiment which was happening?

Aug1213 07:53 AM
DaleSpam

10 
739 
I remember when I took E&M my teacher said that special relativity was built into Maxwells equations.
Lets look at...

Aug1213 04:09 AM
BruceW

6 
628 
I am wondering as to how many metrics have been discovered that obey all the laws of General Relativity?
I am...

Aug1113 08:04 PM
PAllen

7 
571 
I always try to assume that pretty much anything I think of has been thought of before, so I am relatively sure that...

Aug1013 06:37 PM
arydberg

8 
583 
Hi everyone. I'd like you to help me make sense of a question I found about the Michelson Morley experiment. This is...

Aug1013 05:36 PM
Simon Bridge

7 
578 
hi
In a local inertial frame with g_{ij}=\eta_{ij} and \Gamma^i_{jk}=0.
why in such a frame, curvature tensor isn't...

Aug1013 02:03 PM
stevendaryl

22 
1,072 
hi
i read an article by S.carlip about quantum gravity, arXiv:grqc/0108040v1 ,
in this article carlip stated:
why...

Aug1013 12:40 PM
Bill_K

1 
374 
I'm trying to make a chart that displays how much energy it takes a rocket with x mass to reach Y factors of...

Aug1013 12:45 AM
Simon Bridge

10 
667 
Apologies if this is in the wrong forum:
I am reading Biocentrism by Robert Lanza, and one of his arguments is that...

Aug913 07:55 PM
DaleSpam

2 
430 
hello
In MTW excercise 22.6, given a fluid 4velocity u, why the expression :
∇.u is called an expansion of the...

Aug913 01:38 PM
WannabeNewton

9 
517 
I was working on the derivation of the riemann tensor and got this
(1) ##\Gamma^{\lambda}_{\ \alpha\mu}...

Aug913 12:53 PM
ProfDawgstein

3 
477 
I have a short question about the derivative of a given EMTensor.
##\rho## = mass density
##U^\mu## = 4 velocity...

Aug913 08:27 AM
ProfDawgstein

21 
1,049 
Here is an anecdote about Arthur Eddington:
So Eddington thought only he and Einstein understood GR, at some point...

Aug813 04:38 PM
Jolb

24 
1,265 
The cosmological redshift can be understood in terms of time dilation.
In an expanding Universe light travels on a...

Aug813 02:01 PM
Drakkith

45 
2,434 
In Stephane Hawking's bookA Brief History of TimeStephane says that in the past they used to believe thatthe speed...

Aug813 11:06 AM
Harry Wilson

27 
1,234 
The following is a shot in the dark.
Say we have two perfectly reflecting mirrors with equal mass. Which are...

Aug813 05:06 AM
arnesinnema

7 
539 
I'm a little confused about when I would use the 4velocity for a particle on a world line. I got confused the other...

Aug813 02:06 AM
WannabeNewton

1 
400 