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Feb2313 08:40 AM
ZapperZ

1 
40,919 
The section of the Usenet Physics FAQ titled "Experimental Basis of Special Relativity" has been cited here many...

Dec3107 02:06 AM
jtbell

0 
40,574 
Hello. When one is converting between coordinate systems, the Jacobian arises as a necessary consequence of the...

Jan1911 10:20 AM
bcrowell

2 
1,695 
I'm a little confused about what an observer would see while watching something fall into a black hole.
From what...

Jan1911 06:39 AM
lavinia

24 
3,030 
if light can be affected by gravity then why is it said to have no mass? and sience light is affected by gravity.. if...

Jan1911 05:57 AM
DaleSpam

46 
6,830 
To travel by space ship to Andromeda (2.5 million light years) within a life time (say 50 years) you would have to...

Jan1811 03:39 PM
Nabeshin

8 
3,074 
In the LHC, what radial and tangential Gforces does a proton experience where from start to finish? Where would each...

Jan1811 03:10 PM
teve

0 
993 
What are the symmetries determined by FRW spacetime? I guess they include Lorentz symmetry, rotationally and...

Jan1811 01:58 PM
Ich

6 
2,455 
Ok so in Einstein's thought experiment with the train, everything makes sense except...
Einstein is stating that an...

Jan1811 08:29 AM
JesseM

7 
1,040 
Hi,
Is Spacetime inside the Quantum Vacuum or is the Quantum Vacuum inside or fill up Spacetime?

Jan1811 12:25 AM
Alfrez

2 
821 
Is it
\nabla_\mu\nabla_\nu A^\alpha={A^\alpha}_{;\mu\nu}
or
\nabla_\mu\nabla_\nu...

Jan1711 10:32 PM
pellman

3 
1,412 
Hi
I tried using the search function but it keeps timing out on me. Anyway I'm trying to find a good description...

Jan1711 04:59 PM
jason12345

6 
7,912 
This is a two part question. Part 1: I am embarrassed to ask but if someone could please help me. I was thinking about...

Jan1711 10:10 AM
JesseM

23 
2,818 
I was reading in a paper for Chamseddine the following:
"In the past many attempts were made to construct
gravity...

Jan1711 05:04 AM
haushofer

10 
2,448 
I am confused with some of the aspects of time dilation. I read the derivation (the one with the mirrors) and I...

Jan1611 11:08 PM
merry

10 
2,260 
If gravity and acceleration are "cousins," How much faster does time proceed on Earth than floating motionless (or...

Jan1611 08:21 PM
poeteye

10 
2,555 
I'm not very fund of the subject, but what i know is that the Schwarzschild metric and other known solutions for...

Jan1611 03:09 PM
atyy

4 
917 
Why must the 4momentum for photons p^\mu =(\frac{h\nu}{c},\frac{h\nu}{c} \textbf{e}) transform as a 4vector in...

Jan1611 02:09 PM
CompuChip

2 
1,041 
I'd like to start by mentioning that I have very little in the way of experience on the subject, so forgive me if my...

Jan1511 09:23 PM
JesseM

11 
1,470 
So I am an engineering graduate trying to teach myself some general relativity.
I have tried to solve the Einstein...

Jan1511 01:57 PM
Mentz114

4 
2,610 
I do not fully understand the time dialation formula, if the answer is nearer to 1 does that mean time itself under...

Jan1511 01:30 PM
JesseM

3 
833 
In the process of proving that the d'Alembert operator
is invariant under Lorentz transformations, it was...

Jan1511 12:02 PM
elemental09

2 
1,643 
Q.) If i were to travel at 100,000 m/s in an exact horizontal line away from earth for approximately 1 year, when i...

Jan1511 09:33 AM
nismaratwork

4 
1,453 
Suppose you have a source that send a very strong straight beam of light (say laser )
Then you direct the light...

Jan1511 07:47 AM
DaleSpam

59 
7,631 
Is there any merit to the idea that all black hole singularities are in essence one and the same singularity?

Jan1511 02:49 AM
Phrak

13 
1,373 
Can someone give a definition of Killing Horizon along with a few examples that clearly illustrate the difference...

Jan1411 08:44 PM
AEM

0 
778 
Can anyone please tell me what does SPEED OF LIGHT WITH RESPECT TO AN OBSERVER mean?
Some explain it like this: If...

Jan1411 02:43 PM
ghwellsjr

21 
2,543 
I read papers claiming that the phase of a plane wave (acoustic and electromagnetic) is not an invariant. Taking into...

Jan1311 10:02 PM
jason12345

18 
4,175 
In flat space time the Lagrangian for the EM potential is (neglecting the source term)
...

Jan1311 05:26 PM
bigubau

4 
1,313 
This may be pretty basic but how can black holes have different masses, rotate, obtain material or have mass if black...

Jan1311 09:33 AM
Naty1

3 
608 
It is often stated that the one way speed of light cannot be measured and that the isotropic speed of light is just an...

Jan1311 07:26 AM
Qreeus

63 
7,305 
In canonical approach to GR we define certain foliation \Sigma\times\mathbb{R}
of the spacetime so that we can...

Jan1311 06:56 AM
paweld

0 
584 
Hi all,
Just a question i was wondering about. We know that in electrodynamics the Lagrangian is invariant under a...

Jan1311 03:22 AM
sheaf

3 
939 
I have a question about covariant and contravariant vectors. I tried making concrete examples and in one example I...

Jan1311 12:45 AM
dyb

4 
1,778 
My understanding of Hawking Radiation is that a particle and antiparticle form at the event horizon, the particle...

Jan1211 08:40 PM
George Jones

5 
1,718 
Hello,
Anyone has figure or web site which illustrates how foliation of space time hypersurfaces look like or what...

Jan1211 04:58 PM
berkeman

20 
3,495 
Hi,
I've seen many variations of explanations of the twin paradox using special relativity, but i haven't...

Jan1211 09:56 AM
Mike_Fontenot

46 
4,654 
This topic has been dealt with many threads, in various aspects. I want, in this thread, to set up an example focusing...

Jan1211 08:56 AM
PAllen

27 
3,085 
Why did Michelson assume that ether is moving ?
I mean why didn't he assume that Ether doesn't move and that is why...

Jan1211 07:46 AM
Dark_knight90

9 
1,527 
Can anyone explain to me what exactly is a charged black hole?Where is the charge?Is it on the singularity or...

Jan1211 07:05 AM
phyzguy

1 
970 
I have trouble getting my head round gravity. How can two objects influence each other at a distance in a vacuum. I...

Jan1211 05:59 AM
DaleSpam

2 
992 
Is this a paradox?
We have a satellite orbiting at a significant amount of the speed of light around the earth.
...

Jan1111 10:22 PM
NanoPassion

22 
2,061 