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Feb2313 08:40 AM
ZapperZ

1 
37,405 
The section of the Usenet Physics FAQ titled "Experimental Basis of Special Relativity" has been cited here many...

Dec3107 02:06 AM
jtbell

0 
37,162 
Hello,
It's well known that the action for a relativistic point particle is:
S=m\int...

Nov2210 02:08 AM
raul.cuesta

2 
919 
I first pondered this a number of years ago but I've never formally studied physics or known anyone who has, so I've...

Nov2210 01:29 AM
John232

6 
1,408 
I'm currently reading DF Lawden's book Introduction to Tensor Calculus, Relativity and Cosmology. He coverss the idea...

Nov2110 03:54 PM
dgOnPhys

3 
620 
i have tried many texts and searched but can't find particular mathematical proof or explanation of how sp.theory led...

Nov2110 03:04 PM
tinytim

8 
2,515 
Hi there,
Can anyone point me in the direction of any papers that explicitly derive the equations of motion in f(T)...

Nov2110 06:13 AM
birdhen

0 
739 
Hi.
I am learning special Relativity and I am seeing that the answer to the twin paradox involves the Doppler effect,...

Nov2110 03:06 AM
ghwellsjr

13 
3,093 
When a moving observer views a stationary meter stick, it appears contracted. The stationary observer measures it at...

Nov2010 11:55 PM
ghwellsjr

40 
3,330 
I have read some books by brain Greene in whch he discusses the concept of fixed moments in time, never changing, He...

Nov2010 10:26 PM
Fredrik

1 
1,110 
Here is Max Born explaining the crash of a train, in which the train is regarded to be at rest:
There are two...

Nov2010 07:11 PM
bcrowell

30 
2,565 
I was just checking out an article that talked about scientists who were able to slow light to 38 mph. they went on to...

Nov2010 01:19 PM
michelcolman

4 
978 
I'd like to know whether the concept of spacetime still exists today
My physics teacher doesn't like to believe...

Nov2010 12:26 PM
DaveC426913

5 
2,875 
While listening to "Science Friday" on NPR today, I heard a Swiss physicist explaining that scientists can now produce...

Nov1910 05:14 PM
N99JH

8 
1,205 
I have wondered about when, during collapse, Hawing radiation starts (given that an outside observer never sees the...

Nov1910 02:43 PM
PAllen

0 
977 
Hi,
I can't say I've really ever done much relativity but this made me wonder. Imagine we have some frame...

Nov1910 11:58 AM
bcrowell

1 
926 
1) Consider that one way light speed is anisotropic.
2) Use the Einstein method to synchronize all the watches by the...

Nov1910 11:13 AM
DaleSpam

50 
4,724 
Dear SA/Ms:
I am seeking feedback from active and inactive SA/Ms regarding both the current and possible future...

Nov1910 09:28 AM
Ich

19 
470 
Hey there, I'm having a real hard time understanding exactly how to manipulate tensors (let alone know what they...

Nov1910 08:39 AM
Mentz114

1 
1,952 
Locally, Fermi normal coordinates are designed to correspond with direct measurement of distances (born rigidity). I...

Nov1910 04:18 AM
pervect

1 
736 
I thought I'd present some plots for the Ferminormal coordinates (only in the rt plane) for someone falling into a...

Nov1910 03:37 AM
pervect

12 
2,032 
I think it's fairly well known that Einstein made an incorrect prediction in his 1905 paper on special relativity....

Nov1810 06:49 PM
pervect

18 
2,444 
I will be glad if some one can help me understand
When we perturb schwarzschild metric with linear perturbation we...

Nov1810 12:34 PM
vaibhavtewari

0 
1,333 
So if you were to take the twin paradox, but make it so instead of the ship turning around and going to earth, the...

Nov1810 12:31 AM
John232

8 
980 
Whenever you read about entangled particles, and how measuring one of them "immediately" changes the other, the...

Nov1710 05:30 AM
John232

55 
5,919 
Can someone help me with speed relative to different objects!!!
Nearly everything in everything in everyday life is...

Nov1710 04:44 AM
John232

26 
2,040 
Ever since I joined this forum, I have been adamant about my belief that one needed to include a consideration of...

Nov1610 11:48 AM
MikeLizzi

0 
546 
Hello everyone ,
While studying Special Theory of Relativity , I got stucked with a conceptual problem and need
a...

Nov1610 01:06 AM
JesseM

18 
2,262 
I've thought about this one a few times in the past and can't wrap my head around it, how can space or rather nothing...

Nov1510 10:56 PM
Feullieton

30 
3,952 
I am having difficulty working out one of the steps in Einstein's original SR paper, in the Section entitled "Dynamics...

Nov1510 09:50 PM
SamRoss

7 
1,853 
I'm sure someone else must have come up with this (the description in the third paragraph), but I haven't seen it....

Nov1510 06:40 PM
DaleSpam

5 
860 
Hello everyone...can anyone tell me what is the modified expression for the gravitational potential in GR which takes...

Nov1510 06:36 PM
bcrowell

2 
836 
From the equation of time dilation we can deduce a consequence that surprise me . If we know that in our frame system...

Nov1510 05:50 PM
Aemilius

3 
1,081 
What is the major difference or differences of Inertial and nonInertial frame of reference??
Is it only:
...

Nov1510 01:32 PM
ManishR

3 
4,460 
Lets say we manage to build a spaceship 30miles wide and long that is capable of reaching to 99.99% the speed of...

Nov1510 08:13 AM
HallsofIvy

2 
897 
As 2 time pieces are moving relative to each other in a non accelerated reference frame, they will both see the other...

Nov1510 12:17 AM
JesseM

16 
1,401 
I thought this may be an isolated idea but on doing a search on the web, there seems to be a common interest in the...

Nov1410 06:40 PM
hcgpi

58 
6,412 
1) So let's say we have twin A and twin B.
2) Twin A stays on Earth.
3) Twin B goes on a trip nearly at the speed of...

Nov1410 02:01 PM
JesseM

128 
7,755 
Sergei Winitzki has a very nice copylefted GR book:...

Nov1410 10:16 AM
bcrowell

7 
1,310 
I don't possess enough knowledge of GR to know if this proposal is feasible (or even remotely possible) I would...

Nov1410 04:44 AM
Jonathan Scott

5 
998 
I would like to start a brain storming thread, listing all the possible complications that would arise from NOT having...

Nov1310 07:14 PM
lugita15

18 
1,313 
Hello all,
I'm new to GR and trying to understand everything in general now...
I was looking at pictures like this...

Nov1310 08:03 AM
Jonathan Scott

18 
1,985 