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Feb2313 08:40 AM
ZapperZ

1 
42,457 
The section of the Usenet Physics FAQ titled "Experimental Basis of Special Relativity" has been cited here many...

Dec3107 02:06 AM
jtbell

0 
42,107 
Does light have inertia?
Suppose a light pulse is emitted in a moving train in the direction of train’s movement....

May2214 10:40 AM
xox

9 
1,152 
You have two trains sitting on the equator (one on each side of the equator so they don't collide .). Train one is...

May2114 10:32 PM
PeterDonis

3 
561 
1. How do we know that objects mass increase as they approach the speed of light
2. How did whoever figured this...

May2114 01:58 PM
ZapperZ

23 
871 
A couple of questions about this paper, which, unfortunately, I can't access in is entirety...

May2114 12:46 PM
Bill_K

2 
268 
Hi,
I've just started Gravitation and Inertia by Wheeler and Ciufolini. This is really a sort of trasure to me,...

May2114 11:42 AM
WannabeNewton

31 
1,064 
I have been reading GR but I have these gaps in understanding. Can someone help clear them?
1) SR has a...

May2014 09:55 PM
Matterwave

5 
589 
Paul Lutus writes :
Is this true? I always thought strongly that it was not. The example is often given of 2d...

May2014 09:14 PM
BensonBear

64 
2,272 
Hello all,
Brand new member here. I am trying to fully understand the different kinds of masses, i.e. rest mass,...

May2014 04:40 PM
berkeman

29 
1,743 
In a Bianchi IX universe the metric must be invariant under the SO(3) group acting on the 3sphere. Hence, the metric...

May2014 07:50 AM
Bill_K

4 
325 
In a spatially homogeneous model, spacetime is filled with a oneparameter set of invariant hypersurfaces H(t)....

May2014 06:03 AM
Bill_K

2 
363 
I posted about this on a muber of threads, but answers I red didn't really made me clear some confusion about this, so...

May2014 03:58 AM
analyst5

89 
3,112 
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

91 
2,127 
This is basically a followup to some questions from a previous thread regarding Einstein synchronization and other...

May1914 04:10 PM
analyst5

10 
473 
would time dilation occur if for example, i was making a hydrogen atom spin with the center of spin the atom? would...

May1914 03:40 PM
mfb

1 
251 
Is it possible for a riemann manifold to change its curvature?
In practice could the universe in general change its...

May1914 01:42 PM
WannabeNewton

15 
404 
Can we define a threshold velocity V for an object with mass(rest) M which the object at motion need to attain so that...

May1914 08:15 AM
T.M Masike

4 
354 
In my book it says that the Lorentz group O(3,1) includes 'discrete reversals of the time direction'.
What on earth...

May1814 10:21 PM
Aziza

3 
264 
Mathematically,
##T_{\mu_\nu} = 0##
##\Rightarrow~R_{\mu\nu}  \frac{1}{2} R g_{\mu\nu} = 0##
Now multiply both...

May1814 09:25 PM
simoncks

11 
393 
I am intrigued to see what spacetime curvature is like in reality. Most images or ways to imagine it tend to look at...

May1814 08:08 PM
homeomorphic

11 
581 
I think this is a relativity/frame of reference discussion and not QM but if I've got it wrong perhaps a mod can home...

May1814 06:39 PM
DaleSpam

11 
651 
I have been doing a lot of regarding about relativistic physics since my earlier posts and I think I now understand...

May1814 03:30 PM
pervect

9 
335 
Hi! I have been pondering a scenario involving a paradox with length contraction. I brought it up with my physics...

May1814 03:15 AM
ghwellsjr

51 
2,137 
Hello Everybody,
It is quite good experience to spend time on this helpful forum, but I am posting here for the...

May1814 02:27 AM
bushramajeed

0 
295 
I'm a high school student and I don't know much about this stuff e.g. the Higgs Field but i know that the Higgs field...

May1814 01:28 AM
Matterwave

4 
412 
On the spacetime manifold in general relativity, one chooses a basis at a point and express it by the partial...

May1714 02:59 PM
Matterwave

2 
236 
Hawking said that the horizon area of a black hole never decreases and illustrated that in his Hawking Are Theorem:
...

May1714 12:22 PM
PeterDonis

5 
262 
Hello, I'm going through Landau and Lifshitz "The Classical Theory of Fields" this summer with a friend and in section...

May1614 11:11 PM
electricspit

3 
293 
If g_{ab},0 = 0 (g does not depend on time), then the manifold must have a timelike killing vector.
How can one...

May1614 03:23 PM
PeterDonis

3 
326 
When a particle is traveling very close to c. Will its mass actually increase and therefore its ability to resist...

May1614 01:43 PM
Doc Al

18 
626 
Suppose that we have a body that is moving at a straight line, inertially wrt to another frame. If it starts to move...

May1614 12:20 PM
WannabeNewton

40 
1,255 
In Bianchi IX, the isometry group is the group that admits the same lie algebra as the lie algebra of SO(3). What...

May1614 04:34 AM
befj0001

0 
253 
All Bianchi type spacetimes have metrics that admits a 3dimensional killing algebra. They are in general not...

May1614 01:13 AM
befj0001

7 
467 
If a a object is falling in a gravity field with infinitly long radius. can it eventually travel faster than the speed...

May1514 02:53 PM
xox

34 
1,728 
I know several raytraycing results for static Schwarzschild black holes, but I have never seen something similar for...

May1514 10:49 AM
tom.stoer

8 
634 
hello
i want to derive the Transformation of acceleration between two reference frames
i searched in internet and...

May1514 09:20 AM
xox

11 
426 
I'm reading an old article published by Kaluza "On the Unity Problem of Physics" where i encounter an expression for...

May1514 07:58 AM
Bill_K

3 
254 
We know the equation E=pc or P=mc both of them are avaliable for photon.But photon is a massless particle.How can that...

May1414 01:03 PM
DaleSpam

18 
844 
While contemplating the twin paradox the thought occured to me that every observer should see the universe as being...

May1414 11:50 AM
pervect

19 
638 
I've researched about it and watched a few videos, but I can't seem to get my head around it. Would saying that "it's...

May1414 08:08 AM
DaleSpam

55 
2,506 
First off I'd like to say my understanding of physics isn't very good, so I'm sorry if this question is a non...

May1314 09:36 PM
DaleSpam

10 
548 