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Feb2313 08:40 AM
ZapperZ

1 
42,308 
The section of the Usenet Physics FAQ titled "Experimental Basis of Special Relativity" has been cited here many...

Dec3107 02:06 AM
jtbell

0 
41,942 
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 
410 
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 
380 
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 
456 
Hi there,
I think I understand how, using Lorentz transformations, I can find relative speeds of objects within...

Mar2514 12:31 PM
Nugatory

3 
361 
Two questions, based on the same situation: in ...

Mar2514 10:27 AM
nomadreid

2 
315 
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 
325 
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 
286 
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 
442 
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 
383 
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 
780 
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 
9,374 
Looking at the Einstein equation, stresses can cause a deformation of space time.
This link here...

Mar2314 08:36 AM
Vanadium 50

7 
499 
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 
451 
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 
4,135 
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 
414 
∇_{\mu}g_{\alpha\beta}=0 is the metricity equation (∇ the covariant derivative).
However, I wondered whether also...

Mar2114 06:52 PM
dextercioby

4 
384 
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 
888 
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 
740 
The stress energy momentum tensor of the Einstein field equations contains multiple density terms such as the energy...

Mar2014 07:46 PM
pervect

4 
421 
There are various explanations for Thomas precession in the literature and I would like to come to a deeper...

Mar2014 05:20 PM
WannabeNewton

70 
3,835 
I've been studying the Einstein field equations. I learned that the Ricci curvature tensor was expressed as the...

Mar2014 02:01 PM
spacetime

7 
596 
What is the gravitational binding energy in GR in the spherically symmetric case?
I calculate...

Mar2014 11:36 AM
pervect

4 
378 
Consider two points A and B (Fig.1) at rest in S frame having a distance L0 between them (a long scale may be imagined...

Mar2014 09:38 AM
Nugatory

11 
663 
Hi,
While reading Sean Carroll's book, I came across the following statement:
Okay so this has me confused....

Mar1914 06:15 PM
maverick280857

2 
342 
I'll ask that you forgive me if my question seems to "basic" or simple for some of the more professional posters. I...

Mar1914 03:15 PM
A.T.

3 
435 
Hi guys, I'm reading a text regarding different possible ways of synchronizing clocks in an inertial frame, so maybe...

Mar1914 12:43 PM
DaleSpam

7 
504 
At v = c, time (hence physics) stands still.
You can never reach c, but lets say near enough.
Therefore if you...

Mar1814 03:39 PM
sshai45

15 
676 
Let's say we have a metro tunnel that is a circular loop with 1 m x 1 m rectangular cross section. The tunnel is 100...

Mar1814 10:18 AM
DaleSpam

3 
437 
Never mind. Please delete this post

Mar1714 11:35 PM
bcrowell

1 
345 
Hello all,
In Carroll's on page 109 it is pointed out that for derivation of the geodesic equation, 3.44, a...

Mar1714 03:37 PM
victorvmotti

26 
1,223 
While Planck time is usually regarded as the shortest unit of time, isn't the shortest unit of time that can exist is...

Mar1714 01:58 PM
mfb

5 
515 
This paper discusses the Bell spaceship paradox:
Petkov, "Accelerating spaceships paradox and physical meaning of...

Mar1714 12:34 PM
PeterDonis

7 
512 
As I've red, different points on the rotating disk, or rotating object have different velocities and so they should...

Mar1714 12:13 PM
ghwellsjr

3 
448 
I'm trying to understand inflation (in the cosmic sense). I know that ultimately that's a subject that involves both...

Mar1714 12:11 PM
PeterDonis

1 
347 
I am wondering how big the local coordinate charts in a coordinate atlas of General Relativity can be. Is it just a...

Mar1714 08:51 AM
DaleSpam

3 
337 
I was wondering since it is usually foliated into 2spheres and these are not themselves parallelizable(only the...

Mar1614 03:48 PM
TrickyDicky

6 
501 
Let's say we have a long cylinder and two pistons inside the cylinder, and some vapour between the pistons.
Now we...

Mar1614 11:14 AM
yuiop

24 
1,058 
I see a number of gravitational wave analytic solutions with the metric given in terms of Rosen coordinates. I have no...

Mar1614 05:32 AM
Bill_K

5 
515 
Hi guys, this is my first post, I'm a newbie regarding physics and relativity so I hope you can help me here.
I've...

Mar1514 10:36 PM
gravuniverse

41 
1,794 
Perhaps I am redshifted, but I just saw a video demonstrating space/time as a loaf of bread and depending on how it...

Mar1514 11:38 AM
yuiop

10 
680 