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Feb2313 08:40 AM
ZapperZ

1 
37,494 
The section of the Usenet Physics FAQ titled "Experimental Basis of Special Relativity" has been cited here many...

Dec3107 02:06 AM
jtbell

0 
37,229 
I was hoping someone could help me with a simple physics question I've been mulling over, I've failed to find an...

Apr214 06:07 AM
Nugatory

12 
538 
Hello All,
Sorry if my question seems to be elementary. I am trying to find out a little bit details of the Riemann...

Apr214 01:13 AM
Matterwave

3 
333 
Hi everybody,
As you know, the Einstein field equation
R_{μ\nu}  1/2Rg_{μ\nu} =κT_{μ\nu}
implies that at...

Apr114 11:31 PM
bcrowell

10 
472 
Hello,
I have a question, whether is possible to looking for Killing Vectors (KV) in this way (I know about...

Apr114 07:26 PM
WannabeNewton

4 
348 
Hi, I've heard and read that if someone was to fall towards a black hole, say feet first, they would undergo...

Apr114 06:23 PM
liron

7 
463 
I'm trying to work out:
(∇f)^2 (f is just some function, its not really important)
While working in curved...

Apr114 05:02 AM
TrickyDicky

7 
306 
Hi,
I've found geodesic equations for the metric:
\begin{equation}
ds^{2} = c^{2} \alpha dt^{2} + \frac{1}{...

Mar3114 10:35 AM
Bill_K

1 
282 
In an expanding universe that is modeled by the FRW metric we assume that scale factor of the "present epoch" is unity...

Mar3014 01:33 PM
victorvmotti

4 
303 
Hi All. Layman question.
In the twin's paradox, why one of the brothers is older when they meet again?. if movement...

Mar3014 05:05 AM
Nugatory

63 
4,676 
Hey everyone,
Recently I have been working on my teaching degree and doing field experience. Because relativity is...

Mar3014 02:30 AM
Bandersnatch

6 
453 
In Padmanabhan's Theoretical Astrophysics by defining a ratio for comparing gravitational potential energy with...

Mar2914 07:58 PM
bcrowell

9 
471 
Ok, I have an experiment, well actually it is more of a question than an experiment. I have a very elementary...

Mar2914 04:09 PM
delsaber8

15 
549 
I couldn't work out exactly where to post this. I've heard several times that QM and General relativity "contradict"...

Mar2914 11:22 AM
PeterDonis

2 
281 
So basically, my physics class has begun focusing on SR. And i just wanted to clarify something. I have been...

Mar2914 02:44 AM
ghwellsjr

6 
391 
v=? delta what/which X(distance) over delta what/which T(time)
http://en.wikipedia.org/wiki/Special_relativity

Mar2814 10:02 PM
Fredrik

21 
1,202 
Hello, Im a newguy here, so if my question dont belong to this section, please let me know.
My question:
In...

Mar2814 08:21 PM
bcrowell

5 
387 
Hello,
Im looking for some time dependent exact solution of Einsteins eqs. If Im right (if not please correct me)...

Mar2814 02:52 PM
Chestermiller

6 
295 
I know the reasons why the relativistic mass equation (M= gamma Mo) is out of favour with what seems to be a majority...

Mar2714 12:58 PM
DrStupid

37 
1,207 
Can a magnetic field bend spacetime?

Mar2714 01:34 AM
Drakkith

1 
337 
So the angular diameter distance is given by the angle it extends in the sky and its actual size x
d_A=...

Mar2614 02:38 PM
kuecken

0 
267 
In an old (2008) thread, DrGreg posted this transformation from a Minkowski chart to a Rindler chart
...

Mar2614 02:24 PM
PAllen

16 
460 
So I have just been introduced to indices, four vectors and tensors in SR and I'm having trouble knowing exactly what...

Mar2614 10:24 AM
vanhees71

5 
326 
I am using a wikipedia page, Derivation of the Lorentz transformations and a lot of historical papers. To follow...

Mar2614 07:13 AM
ANvH

5 
302 
The three main effects of SR occur in inertial frames and change the description of spacetime relative to a...

Mar2514 12:32 PM
A.T.

8 
350 
Hi there,
I think I understand how, using Lorentz transformations, I can find relative speeds of objects within...

Mar2514 12:31 PM
Nugatory

3 
315 
Two questions, based on the same situation: in ...

Mar2514 10:27 AM
nomadreid

2 
250 
Hi All
Gravitation seems very interesting field to me. One of the most mysterious field of studies, which is having...

Mar2514 01:40 AM
Sethi

0 
276 
Biking at near the speed of light
If a biker is going at 0.99c, an observer standing still would notice his...

Mar2414 07:48 PM
jartsa

38 
936 
https://www.youtube.com/watch?v=c3fJRRCAIdk This is a video of the 'barking dog' chemistry experiment captured with a...

Mar2414 06:57 PM
russ_watters

1 
236 
Reading over Alcubierre's paper on his "warp" drive (http://arxiv.org/abs/grqc/0009013), the metric in equation 3...

Mar2414 11:55 AM
PAllen

2 
381 
Greetings,
I've been learning about special relativity and most of the learning media included a part of general...

Mar2414 11:46 AM
drichard

3 
316 
I just watched a video that kind of warped my understanding of time dilation. It said that not only would time appear...

Mar2414 06:33 AM
ghwellsjr

10 
656 
This is a puzzle based on a purported "refutation of GR" on this webpage, which is also the subject of a subthread in...

Mar2314 02:42 PM
DaleSpam

92 
8,187 
Looking at the Einstein equation, stresses can cause a deformation of space time.
This link here...

Mar2314 08:36 AM
Vanadium 50

7 
379 
I was just wondering what would the definition of the inertial frame be, since as I've understood the description it...

Mar2214 11:01 AM
A.T.

3 
363 
Could there be an absolute 'state of reference' somewhere in the universe, perhaps at the location of the original...

Mar2214 05:56 AM
DaleSpam

135 
2,982 
Since the speed of light is a constant, no matter what location from which a search of the universe is made, matter...

Mar2114 07:02 PM
PAllen

5 
352 
∇_{\mu}g_{\alpha\beta}=0 is the metricity equation (∇ the covariant derivative).
However, I wondered whether also...

Mar2114 06:52 PM
dextercioby

4 
306 
So I created an account here just so I could ask this burning question. I keep looking online and through other...

Mar2114 04:07 PM
pervect

12 
703 
I think that is a fundamental question of why we need Tensor when dealing with GR?
Quoting from the text book...

Mar2114 01:17 PM
WannabeNewton

12 
620 