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Feb2313 08:40 AM
ZapperZ

1 
40,457 
The section of the Usenet Physics FAQ titled "Experimental Basis of Special Relativity" has been cited here many...

Dec3107 02:06 AM
jtbell

0 
40,116 
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 
326 
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 
898 
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 
940 
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 
416 
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

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467 
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 
448 
I read recently that "...at present only GR theory predicts the required 13 parameters for agreement with critical...

Jun1214 09:57 AM
WannabeNewton

1 
246 
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

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457 
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 
273 
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

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989 
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 
585 
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

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921 
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 
386 
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 
1,447 
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 
462 
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 
705 
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 
452 
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 
340 
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 
1,617 
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 
355 
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 
742 
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 
683 
I have seen numerous articles referencing the teleportation of information over a distance of 3 meters using quantum...

Jun314 05:05 PM
mfb

5 
403 
What is the proof of Einsteins famous equation E = mc2 ?

Jun314 04:30 PM
PeterDonis

86 
2,708 
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 
491 
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 
350 
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 
359 
I thought I understood how stellar aberration conformed to Special Relativity. The CHANGE in that angle comes from the...

Jun214 03:31 PM
micromass

102 
3,431 
So, I lay a rope into a black hole, rope leaves the reel at velocity 0.99 c.
When I observe the lower end of the...

Jun214 02:37 PM
.Scott

9 
597 
Black hole A moves at slow velocity, and there's an Einstein light clock hovering near the event horizon.
Black...

Jun214 01:26 PM
PeterDonis

7 
363 
I've been meaning to ask this for some time, and now I've plucked up the courage! It is puzzling to me that many...

Jun214 05:18 AM
WannabeNewton

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287 
I have a question.
I am in a frame. I construct a spring scale and weigh a ball to be 200 lbs on the floor. I feel...

Jun114 06:04 PM
randyu

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928 
In an inertial reference frame  and zero gravity field  we believe that any passing photons go in Euclidean straight...

Jun114 12:10 PM
pervect

8 
506 
I am trying to understand this apparent "paradoxes" but probably i am missing something important.
Imagine that...

Jun114 08:17 AM
ghwellsjr

1 
373 
Biking at near the speed of light
If a biker is going at 0.99c, an observer standing still would notice his...

May3114 11:29 PM
liometopum

44 
1,703 
Is there time inside of a black hole?

May3114 07:59 PM
PeterDonis

33 
1,346 
Our latest understanding of gravity is based on Einstein's general theory of relativity which says gravity is geometry...

May3114 04:46 PM
atyy

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410 
Hi.
So the whole premise of special relativity seems to me to be hinged on the immutability of the speed of light,...

May3014 07:49 PM
Simon Bridge

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819 
If yes, does dark energy define a frame of absolute rest?
In the Einstein field equations, the cosmological...

May3014 07:26 PM
PeterDonis

1 
297 
Einstein is quoted as saying "Time is an illusion" others have made utterances throughout the scientific and added...

May3014 10:35 AM
jbriggs444

11 
499 