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Feb2313 08:40 AM
ZapperZ

1 
37,397 
The section of the Usenet Physics FAQ titled "Experimental Basis of Special Relativity" has been cited here many...

Dec3107 02:06 AM
jtbell

0 
37,154 
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 
2,469 
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 
483 
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 
353 
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 
661 
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 
240 
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 
543 
Is the Milky Way Galaxy nonrotating or rotating?
Which metric is best suited: Schwarzschild or the Kerr Metric,...

Aug1213 11:57 PM
Mentz114

7 
421 
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 
2,146 
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 
1,667 
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 
398 
How could you tell in an experiment which was happening?

Aug1213 07:53 AM
DaleSpam

10 
726 
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 
619 
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 
564 
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 
581 
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 
567 
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 
1,057 
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 
369 
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 
660 
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 
426 
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 
509 
I was working on the derivation of the riemann tensor and got this
(1) ##\Gamma^{\lambda}_{\ \alpha\mu}...

Aug913 12:53 PM
ProfDawgstein

3 
473 
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 
1,039 
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 
1,246 
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 
2,394 
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 
1,213 
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 
533 
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 
398 
In GR, the geodesic equation for a test particle can be seen in 2 ways.
(1) It is a fundamental postulate...

Aug713 11:46 PM
WannabeNewton

7 
730 
For outside observer, an object falling into black hole seems to freeze at event horizon and never cross the boundary...

Aug613 09:17 PM
WannabeNewton

4 
485 
Hi, I confused about the relationship between light and c on the one hand and massless particles and c on the other. ...

Aug613 12:19 PM
phinds

6 
619 
In his paper, Chou et. al., 2010 has demonstrated that an atomic clock at the height of our head ticks faster than an...

Aug613 02:26 AM
harrylin

138 
4,914 
Hi everyone! I was thinking about gravitational waves and gravitons and I realized that I did not fully understand the...

Aug513 01:09 PM
The_Duck

11 
902 
Einstein reconfirmed
"In the new Kepler study, scientists used the gravitational lensing to determine the mass of...

Aug413 07:03 PM
Mentz114

4 
969 
I would like to have a Star orbiting a Schwarzschild Black Hole if the the velocity and position vectors in the galaxy...

Aug413 10:04 AM
DaleSpam

10 
582 
At the moment I'm reading a little bit about the connection between the Lorentz group SO^{+}(1,3) and its covering...

Aug313 10:56 AM
parton

0 
412 
In the regular hall effect we calculate like this
F=qE=qvB then E=vB , now we assume our conductor has width d so...

Aug313 10:40 AM
Nugatory

4 
628 
I’ve got a question.
Say we have a medium traveling through a pipe at speed v. The soundspeed of the medium is vs....

Aug313 10:19 AM
ProfDawgstein

1 
420 
hi
some black holes are inner and outer horizon!!
what's this means?
inner and outer?
what happen between them?

Aug313 08:13 AM
Naty1

3 
856 
Hello Forum
I have constructing a Michelson Interferometer using sodium light. For viewing the fringes, I have used...

Aug213 10:51 PM
itsnaresh

2 
509 