
Before posting anything, please review the Physics Forums Global Guidelines.
If you are seeking help with a...

Feb2313 08:40 AM
ZapperZ

1 
42,734 
The section of the Usenet Physics FAQ titled "Experimental Basis of Special Relativity" has been cited here many...

Dec3107 02:06 AM
jtbell

0 
42,379 
Quoting from Wikipedia:
"Time dilation would make it possible for passengers in a fastmoving vehicle to travel...

Jan2112 06:17 PM
kcdodd

5 
1,759 
Hi 'body,
ok, this is a well known issue, but i still can't find a valid explanation of why FTL implies time travel....

Jan2112 05:19 PM
frakie

11 
2,067 
I am starting my honours project on colliding plane gravitational waves and I am learning about the PetrovPenrose...

Jan2112 04:22 PM
purakanui

5 
1,645 
In trying to understand why matter curves space i thought up a model that has the curiosity of suggesting the concept...

Jan2112 03:29 PM
torquil

11 
5,146 
While attempting to wrap my head around the classical Twin Paradox, I asked myself the following. So far I have not...

Jan2112 02:04 PM
plbeale

36 
3,719 
Cosnider a universe with only two objects, a planet and a star...
From the rest FoR of the Star, the planet appears...

Jan2112 01:42 PM
Nugatory

18 
3,500 
What we humans know about the center of mass of Universe?

Jan2112 10:13 AM
tom.stoer

30 
9,917 
I'm just curious, in the Coulomb gauge changes made locally to the scalar and vector potential fields are propagated...

Jan2112 03:25 AM
tom.stoer

1 
1,048 
Hello all,
Special relativity tells that space and time should be seen as a single four dimensional space time....

Jan2012 12:56 PM
DaleSpam

3 
1,097 
Me and a few friend are currently having a large argument whether time is actually changing when a shuttle is moving...

Jan2012 11:13 AM
DaleSpam

34 
2,583 
We know that
1. Mass causes bend in spacetime and this is the how gravitation occurs.
2. The formula for...

Jan2012 10:55 AM
bcrowell

2 
988 
Okay, so I'm no physicist, but I just had a random thought. So they say that traveling at the speed of light is...

Jan2012 10:44 AM
Tracer

5 
1,316 
What happens if two objects travel at speed 1/2c in opposite directions?
Like suppose two ships left the ISS in...

Jan2012 06:44 AM
Vanadium 50

5 
941 
Hi,
I have a very basic question, which confuses me, probably due to sloppiness.
A particle follows a path...

Jan2012 04:16 AM
TrickyDicky

9 
1,281 
Hello.
According to link.
http://einstein.stanford.edu/MISSION/mission1.html
we have
0.000011 degrees/year due...

Jan2012 04:00 AM
Alvydas

2 
1,008 
Hi,
I am doing a problem of GR dealing with weak field limit equations. After decoupling the static and dynamical...

Jan2012 02:04 AM
Matterwave

4 
1,157 
I am wondering how space geographers would measure curvature of space around a large isolated star. i am thinking of...

Jan2012 12:45 AM
PAllen

8 
1,422 
Hi all,
This question has been baffling me for quite some time...
Let's say that a tiny black hole is already...

Jan1912 05:43 PM
PeterDonis

30 
3,228 
Curious
Why does the equivalence of mass/energy involve the speed of light at all?
Is it because Einstein...

Jan1912 05:30 PM
Necrostate

13 
1,723 
reading about aberration of starlight i discovered that the usual aberration formula can be written either as cos a'=...

Jan1912 04:38 PM
kostis

0 
1,376 
Hey! I'm trying to understand time dilation in terms of minkowski diagrams.
Below I've added a diagram showing the...

Jan1912 02:44 PM
bobc2

12 
2,287 
The way I've been reading it, elliptic geometries are due to a positive Gaussian curvature, while hyperbolic...

Jan1912 08:27 AM
Naty1

5 
1,528 
I was thinking yesterday about a scenario where a ray of light passes a massive body and is deflected. If I were in a...

Jan1912 12:58 AM
pervect

8 
1,396 
Alright, so excuse my ignorance, but I have no idea why the choice he uses for boosts is "convenient"
Just to make...

Jan1912 12:09 AM
Elwin.Martin

4 
1,178 
Does the relative motion of a thing slow down the relative motion of a thing? Hope that makes sense or you can work...

Jan1812 08:53 PM
jartsa

10 
1,750 
Say I became a particle and I'm moving at 0.9c towards a spaceship. My course is parallel to the ship, and I'm seeing...

Jan1812 05:13 PM
ghwellsjr

4 
1,129 
As stated in SR, mass of the object increases with its velocity right?
Lets assume that all the objects in the...

Jan1812 04:03 PM
SHISHKABOB

36 
3,549 
What is the difference between both theories?
From what I've heard, GR replaces SR as the more correct theory, but...

Jan1812 12:46 PM
joan pendleto

2 
1,219 
Does the force of gravity travel the speed of light? faster than the speed of light? or is it instantaneous?
Is...

Jan1812 08:58 AM
atyy

41 
26,898 
Please explain me how to derive the Timelike geodesics in Schwarzschild Metric.
Thank you.

Jan1812 01:26 AM
Nilupa

2 
1,713 
I am extremely confused with why time dilation is different from what I've read about traveling at speeds near that of...

Jan1712 11:25 PM
ghwellsjr

1 
1,071 
Hi,guys,What is evidence against and for block universe theory?

Jan1712 10:01 PM
bobc2

14 
3,459 
Hi,
I am familiar with the covariant derivative of the tangent vector to a path, \nabla_{\alpha}u^{\beta} and some...

Jan1712 08:50 PM
Matterwave

3 
1,332 
Hoping someone can clear up a few questions...
At any particular instant in time (from anyone's perspective), is...

Jan1712 08:27 PM
bahamagreen

2 
933 
Hey, Im new here. I know very little about advanced physics and the theory of relativity, enough though I suppose to...

Jan1712 06:15 PM
twitch1

11 
1,063 
This is a dumb question. Thank you for your patience. I understand that acceleration and gravity are one and the...

Jan1712 01:28 PM
PeterDonis

4 
1,142 
I want to know that if one sends a radioactive material in a spaceship at high speed and bring it back, do we find...

Jan1712 08:44 AM
DaleSpam

9 
1,638 
Hi,
The explanation I have been given for why GR breaks down at the quantum level is that GR requires spacetime to...

Jan1712 01:15 AM
tom.stoer

1 
904 
Hi there!
Question on momentum in SR.
I'm trying to understand this holistically...
From what I understand......

Jan1612 11:52 PM
Simon Bridge

1 
894 
I am reading Landau and Lifgarbagez's Classical Theory of Fields, 4th edition. In the beginning of page 18, the...

Jan1612 08:57 PM
qinglong.1397

6 
2,241 