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Feb2313 08:40 AM
ZapperZ

1 
42,439 
The section of the Usenet Physics FAQ titled "Experimental Basis of Special Relativity" has been cited here many...

Dec3107 02:06 AM
jtbell

0 
42,086 
hello everyone, this is my first post on these forums. yesterday i was at the local B&N and bought stephen hawkings "a...

Feb906 11:36 AM
russ_watters

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2,130 
I imagin this thought experiment: a train which travels with the speed of light is trying to enter a tunel which has...

Sep907 03:30 PM
Doc Al

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Can someone explain to me how those who believe relativity also believe that the earth revovles around the sun. I...

May309 05:13 PM
Modman

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

Jun2514 09:23 PM
DaleSpam

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To quote from ‘Time, Gravity and Quantum Mechanics, by W. G. Unruh’;
“A more accurate way of summarizing the lessons...

Mar2408 11:16 AM
my_wan

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If the universe is bounded then there will be an absolute frame of reference.
This could be found by summing all...

Apr108 12:13 AM
rab99

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Roger Penrose is reported to have said:
And I understand that, in Minkowski spacetime, the relative velocity...

Nov2909 03:01 AM
Grimble

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Maybe an old topic.
But if you reflect a light wave, and if the light wave is not coming back in exact the same...

Dec2411 12:53 PM
PAllen

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In the Einstein tensor equation for general relativity, why are there two terms for curvature: specifically the...

May1112 02:00 PM
pervect

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2,128 
When I first learnt time dilation I was given this equation proven using the light clock example.
t = γt'
...

Aug1213 03:34 PM
ghwellsjr

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So, I was just thinking what if the time dimension was a tiny curled up dimension like one of these supposed extra 8...

Jun2610 05:46 PM
DaveC426913

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will the following actions be appropriate
g^{\mu\sigma}\frac{dA_{\sigma}}{d\tau}=\frac{dA^{\mu}}{d\tau}
Please...

Jun711 09:35 AM
bcrowell

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There is a classic result by Tolman, Ehrenfest, and Podolsky that in classical GR, the interaction between pencil...

Jul1711 03:17 PM
yuiop

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Hi, I've red a lot these days about the ladder paradox and I have a question about it, but firste let me quote...

Jun913 04:45 AM
ghwellsjr

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i dont understand a problem :confused:
if i two photons A & B travel in a straight line but in opposite directions...

Jul1206 01:32 PM
robphy

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I ahve always wondered why only the curvature term R_{\mu,\nu} been considered in GR. From differential Geoetry, how...

Feb1308 04:47 PM
geoffc

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I do not know the details, but I have read that some theories allow backwards time travel using wormholes. Backwards...

Dec909 11:56 PM
Dmitry67

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Hello Forum,
if one observer A is at rest, its clock measures proper time. Observer A could look at the clock on a...

Jul512 09:43 PM
Chestermiller

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Are there any resources or texts that treat Minkowski geometry in a purely coordinatefree way?

Sep1612 09:46 PM
bcrowell

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I'd like someone to confirm whether I am on the right track here.
Most formulations of the twin paradox involve a...

Jun213 01:54 AM
tom.stoer

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under which conditions we could say that the same experiment is performed in different inertial reference frames. I...

Jul1306 08:28 AM
clj4

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What will gyro alignment be if ?
Establish a free spinning spherical gyro similar to a GPB gyro; but designed to...

Oct1706 11:18 AM
RandallB

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How many numbers does it take to describe a point in space in GR?

Jan1810 06:32 PM
Spinnor

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I'm a high school chem and physics teacher, participating in a recreational online chem course hosted by MIT.
One...

May2014 01:39 AM
PAllen

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2,123 
This is probably a repeat question from somone somewhere, but here goes. Please fill in the blanks. I don't need a...

Jul3009 04:14 PM
solveforX

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This is another version of bell’s spaceship paradox.
Consider two spaceships A & A’ separated by a distance L, and...

Oct313 09:18 PM
DaleSpam

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Hi all,
I just recently introduced myself to SR theory, and now I'm a bit stuck already (probably like most...

Dec907 01:58 AM
pervect

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Am I right in saying that exotic matter or energy is responsible for the accelerating expansion of the universe? If...

Dec1307 03:25 PM
A/4

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In physics questions, objects are shown to travel at relativistic speeds, like 0.6c or 0.8c. This is all hypothetical,...

Apr2109 01:53 PM
JesseM

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I have encountered a difficulty which arises from my attempt to combine non collinear Lorentz transformations in...

Jul1214 09:46 AM
nixed

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I`ve read that the universes expansion is accelerating. To explain this we have introduced concept of Dark matter and...

Oct2809 03:10 AM
Ich

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2,120 
Probably there's a simple answer for the following question. What prevents a neutral particle falling into a black...

Apr610 09:57 AM
starthaus

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I worked through a simple twin paradox problem, and I think I have the correct solution. However, I wanted to confirm...

May1812 01:45 AM
wmikewells

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From what I understand of GR, time dilates due to the gravity of massive bodies. I like to think of it as the three...

Dec2509 03:00 PM
A.T.

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As you will see this is my first post so I apologize if I have chosen the wrong subforum. My academic training...

Feb2612 10:10 AM
childej

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So i was considering minkowski space which is a 4d manifold, why is that we use the tangent and cotangent space, to...

Mar1912 10:01 PM
lavinia

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Ok. There are some concepts here that I am having trouble reconciling.
I would first like to "stipulate" that for...

Mar1408 07:12 AM
tinytim

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In the following article
...

Jul2411 09:45 PM
bcrowell

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Hi,
I've been listening to a Professor Jim AlKhalil's scipod on time travel. I think this guy is bloody...

Nov1711 06:10 AM
Dickie_Boy

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What is the simplest derivation of the transformation rules for Maxwell's equations in special relativity?
I'm...

Apr514 02:14 AM
Fredrik

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