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Feb2313 08:40 AM
ZapperZ

1 
41,685 
The section of the Usenet Physics FAQ titled "Experimental Basis of Special Relativity" has been cited here many...

Dec3107 02:06 AM
jtbell

0 
41,325 
I think I have come across something that invalidates something one of my Physics professors said back in college,...

Jun2514 09:23 PM
DaleSpam

27 
2,013 
I am planning to start self studying GR and, before choosing a better book to use, I have been flipping through an old...

Jun2514 11:31 AM
WannabeNewton

5 
684 
We have the (I think FRW) metric in the coordinates
y^{0}=t,~~y^{1}=\psi,~~y^{2}=\theta,~~y^{3}=\varphi
...

Jun2414 04:32 AM
ChrisVer

5 
864 
I only understand mass and energy according to Newtonian mechanics,
Where mass is the resistance of a body to...

Jun2314 02:06 PM
pervect

3 
675 
It is wellknown that Newtonian's law of gravitation
\Phi(\vec{r}) = \frac{Gm}{\vec{r}  \vec{a}}
for the...

Jun2314 07:45 AM
stevendaryl

20 
1,870 
A lorentz transformed electric field has it's own name. It's called a magnetic field.
That makes me wonder if there...

Jun2214 10:52 PM
pervect

4 
594 
Hello, I have a doubt regarding the postulates of SR.
The two postulates, according to Schutz, are:
1) No...

Jun2114 08:33 PM
Meir Achuz

122 
7,907 
Under a change of variables:
x^{\mu} \rightarrow x^{\mu}+ \delta x^{\mu}
How can I see how the determinant of the...

Jun2114 06:27 PM
Matterwave

1 
458 
What is stability of Hawking Mass and how to calculate it? Any references will be appreciated. Thanks

Jun2114 01:49 AM
Haelfix

9 
655 
Both the Newtonian theory on gravitation and the General theory of Relativity predict a change in the direction of a...

Jun2014 06:17 PM
Devin

5 
628 
I was browsing through old threads and a user named universal_101 kept asking about why we can use muons as a direct...

Jun2014 04:48 PM
Nugatory

1 
472 
Picture:
  

p >

Jun1914 04:04 PM
PeterDonis

1 
394 
My question is essentially a variation of the Ehrenfest paradox in SR. But hopefully with some experimental data.
...

Jun1814 03:28 PM
WannabeNewton

6 
560 
Hi,
I understand the definition of stationary as existence of a timelike Killing vector field and as a result the...

Jun1814 09:23 AM
WannabeNewton

23 
1,491 
This question needs to be framed:
We track time at the Earth's surface using atomic clocks.
We know that objects...

Jun1614 09:00 PM
WannabeNewton

14 
878 
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 
429 
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 
555 
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 
591 
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 
1,182 
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 
496 
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 
367 
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 
353 
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 
442 
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 
428 
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 
1,194 
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 
450 
Hi everyone:
I just started to learn special relativity but totally being confused about "velocity", "momentum" and...

Jun1414 06:49 AM
Jeffrey Yang

8 
514 
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 
1,620 
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 
332 
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 
931 
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 
972 
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 
432 
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 
483 
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 
455 
I read recently that "...at present only GR theory predicts the required 13 parameters for agreement with critical...

Jun1214 09:57 AM
WannabeNewton

1 
249 
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 
475 
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 
288 
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 
1,012 
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 
617 
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 
974 