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Feb2313 08:40 AM
ZapperZ

1 
42,760 
The section of the Usenet Physics FAQ titled "Experimental Basis of Special Relativity" has been cited here many...

Dec3107 02:06 AM
jtbell

0 
42,398 
Hello,
I have two problems.
I'm going through the Classical Theory of Fields by Landau/Lifshitz and in Section...

Jun1614 05:54 PM
electricspit

4 
470 
If two photons ( A and B ) are traveling in opposite directions from a point in a vacuum will the relative speed of...

Jun1614 04:39 PM
ghwellsjr

9 
629 
i have read that existence of photons as a mass less particles came from the energy momentum equation.
E^2 =...

Jun1614 01:13 PM
Goodver

4 
627 
Something thats been bugging me, but unable to find an answer for..
The speed of light (in a vacuum) is absolute,...

Jun1514 01:48 PM
DaleSpam

33 
1,239 
The stressenergy tensor is an actual tensor, i.e., under a spacetime parity transformation it stays the same, which...

Jun1514 01:45 PM
bcrowell

4 
558 
Consider an unbreakable nail.
A nail of length 10cm moving at 0.866c.
If i stop the nail by hitting its cap, would...

Jun1514 01:44 PM
pervect

8 
400 
I really don't understand what it is and what is the use of constant, like in this equation of transformation. ...

Jun1514 10:14 AM
jtbell

4 
383 
As far as I'm informed time slows down the lower the gravity and the faster we move. Let's say I go out in space with...

Jun1514 12:38 AM
Nugatory

7 
489 
From my understanding, an arbitrary (0,N) tensor can be expressed in terms of its components and the tensor products...

Jun1414 11:38 PM
guitarphysics

4 
462 
I have this crazy and goofy dream to construct an artificial black hole. Not a crude analogue, but the actual...

Jun1414 06:06 PM
putongren

22 
1,301 
To=(time of moving object.)
T=(Time of standing object.)
^=power of number.
sqrt=square of number.(x^1/2)
Law...

Jun1414 01:14 PM
Hepic

7 
470 
Hi everyone:
I just started to learn special relativity but totally being confused about "velocity", "momentum" and...

Jun1414 06:49 AM
Jeffrey Yang

8 
548 
Well I just have one question. Is the existence of wormholes really possible or not?
I've only seen them appearing in...

Jun1314 08:23 PM
HarryRool

40 
1,741 
So light can be bent by a gravitational field, and follows the curvature of spacetime. does light have a gravity field...

Jun1314 05:04 PM
Drakkith

1 
350 
It is very important for me to know how scientists detect the speed of light in details...because there is something...

Jun1314 03:50 PM
PeterDonis

27 
1,019 
So, this has really stirred my interest. To be clear, I'm not citing these as sources, simply linking for discussion;...

Jun1214 07:37 PM
Simon Bridge

9 
1,052 
Hey guys, I was recently thinking about theoretical ways to accelerate objects (spacecraft) and I had the idea that...

Jun1214 03:30 PM
DaleSpam

3 
455 
I know that you probably get tired of weird questions like this so I apologize in advance. I was thinking about...

Jun1214 03:23 PM
pervect

12 
529 
Out of interest I'm studying a book "A first course in general relativity" which is a great book in my opinion because...

Jun1214 10:28 AM
PeterDonis

8 
482 
I read recently that "...at present only GR theory predicts the required 13 parameters for agreement with critical...

Jun1214 09:57 AM
WannabeNewton

1 
264 
So, if I travel in a ship at light speed in a line from earth to space for 10 minutes. Than turn around and travel...

Jun1114 10:21 PM
PeterDonis

13 
522 
I've been reading Dr. Harold G. White's work on recent developments in Warp Field Mechanics, and thought up the...

Jun1114 06:20 PM
PeterDonis

1 
352 
Hi, I'm trying to understand what the nature of gravity is. I know it is a force, and I know that heavy objects tend...

Jun1114 05:32 PM
pervect

16 
1,122 
A interesting question came up to my mind, and it's related to the concept of different synchonization methods. If we...

Jun1114 08:01 AM
WannabeNewton

15 
698 
It is often said that we basically live in the past, since it takes time for light to travel from objects to our eyes...

Jun1014 12:40 PM
pervect

35 
1,060 
In, BBC  Wonders of Universe, Professor Brian Cox explains that universe is stretching and the space that we live in...

Jun1014 05:36 AM
phinds

1 
424 
I have used GRTensorII and Cadabra for some time. And I think Cadabra have great potential for GR. But the current...

Jun1014 04:24 AM
shadi_s10

16 
1,617 
If a planet is traveling through space and distorting space, why does it not slow down? If a boat travels through...

Jun914 10:07 PM
jobermark

4 
525 
Suppose that a wheel is rotating around its axis in free space with no friction, with no external forces acting on it....

Jun914 01:22 PM
WannabeNewton

8 
820 
Let us have an observer moving at some velocity v.
And let our observer have 2 mirrors, one on either side of...

Jun814 06:04 PM
BiGyElLoWhAt

10 
527 
I am reading this paper
http://arxiv.org/pdf/1111.4837.pdf
and I came across under eq12 that the new metric is...

Jun714 06:01 PM
Bill_K

3 
367 
I've read a lot of places about length and time dialation or length contraction of an object relative to an observer,...

Jun714 06:51 AM
DaleSpam

54 
1,814 
The spin 4vector is defined in the rest frame of the particle as s^{\mu}= (0, \vec{s}).
Why is the zeroth...

Jun514 05:13 PM
WannabeNewton

3 
394 
Why is it that the covariant derivative of a covariant tensor does not seem to follow the product rule like...

Jun514 02:15 PM
stevendaryl

20 
853 
Assuming it were possible to build a sturdy enough rod like structure, say equal the length it would take light to...

Jun414 01:51 PM
PAllen

10 
725 
I have seen numerous articles referencing the teleportation of information over a distance of 3 meters using quantum...

Jun314 05:05 PM
mfb

5 
433 
What is the proof of Einsteins famous equation E = mc2 ?

Jun314 04:30 PM
PeterDonis

86 
2,994 
If light has a maximum speed of c, what frame of reference is that speed determined from?
For example, if you were...

Jun314 10:55 AM
D H

7 
573 
I'm confused by something I read, that said: Ref: http://adsabs.harvard.edu/abs/1988AmJPh..56..811B
What does...

Jun314 09:58 AM
randyu

5 
376 
Been reading laymen's books on general relativity and I'm in need some clarification! ...
Line 1: The shortest path...

Jun214 08:35 PM
PeterDonis

6 
411 