Special and General Relativity Forum

Post thread
Join in expert discussion on special and general relativity discussion. Relativity is the dependence of various physical phenomena on relative motion of the observer and the observed objects.
  • Sticky
FAQ: Experimental Basis of Special Relativity
  • · Replies 3 ·
Replies
3
Views
63K
  • Sticky
Insights When Discussing the Twin Paradox: Read This First
  • · Replies 2 ·
Replies
2
Views
7K
  • Sticky
Insights Maxwell’s Equations in a Static, Spherically Symmetric Spacetime
  • · Replies 15 ·
Replies
15
Views
9K
  • Sticky
Insights An Introduction to the Generation of Mass from Energy
  • · Replies 41 ·
2
Replies
41
Views
17K
  • Sticky
Relativity Insights: FAQs on Photons, Gravity, Time Dilation, and More!
  • · Replies 4 ·
Replies
4
Views
22K
I Physical Interpretation of Frame Field
  • · Replies 37 ·
2
Replies
37
Views
1K
I Is this another "paradox" or a veritasium mistake?
  • · Replies 28 ·
Replies
28
Views
914
I Can a Gyroscope in a Satellite Detect Orbit?
  • · Replies 28 ·
Replies
28
Views
4K
A Assumptions of Hawking-Penrose 1970 Singularity Theorem
  • · Replies 35 ·
2
Replies
35
Views
1K
I Gyroscope angular momentum: direction and curvature
  • · Replies 2 ·
Replies
2
Views
408
I Euclidean geometry and gravity
  • · Replies 162 ·
6
Replies
162
Views
4K
I About the notion of non-standard inertial frame
  • · Replies 22 ·
Replies
22
Views
1K
I Is using r as a coordinate in Birkhoff's theorem a limitation?
  • · Replies 22 ·
Replies
22
Views
865
I Question about special relativity and magnetism
  • · Replies 5 ·
Replies
5
Views
535
I The Einstein Clock aka Light Clock
  • · Replies 34 ·
2
Replies
34
Views
2K
B Train Fall Paradox
  • · Replies 6 ·
Replies
6
Views
650
I Integration of energy-momentum pseudotensor for Kerr BH
  • · Replies 4 ·
Replies
4
Views
432
I Question about Parallel Transport
  • · Replies 35 ·
2
Replies
35
Views
1K
A Jackson: justification of the Poynting vector by GR
  • · Replies 38 ·
2
Replies
38
Views
981
I Relativity of simultaneity in actuality
  • · Replies 12 ·
Replies
12
Views
774
I EPR revisited
  • · Replies 3 ·
Replies
3
Views
446
B Why Do Events Freeze For Me at the Speed of Light?
  • · Replies 2 ·
Replies
2
Views
390
B Reciprocal time dilation
  • · Replies 15 ·
Replies
15
Views
2K
B Photon Energy Without Rest Mass – How?
  • · Replies 19 ·
Replies
19
Views
2K
I The wave equation interpretation of special relativity
  • · Replies 10 ·
Replies
10
Views
609
A Is the variation of the metric ##\delta g_{\mu\nu}## a tensor?
  • · Replies 49 ·
2
Replies
49
Views
1K
I Synchronizing clocks at different locations to measure speed of light
  • · Replies 58 ·
2
Replies
58
Views
4K
I Convention for writing $\binom{1}{1}$ tensors in matrix form?
  • · Replies 6 ·
Replies
6
Views
472
I Synchronizing clocks in an inertial frame if light is anisotropic
  • · Replies 65 ·
3
Replies
65
Views
2K
I An invariant while crossing the horizon
  • · Replies 7 ·
Replies
7
Views
388
I I don't see how a black hole's event horizon can be crossed
  • · Replies 73 ·
3
Replies
73
Views
1K
I Variation of the lightning train thought experiment
  • · Replies 26 ·
Replies
26
Views
3K
B Project GRE^2AT - GR on Mt. Ranier
  • · Replies 5 ·
Replies
5
Views
398
I How Is Intrinsic Curvature Measured in Higher Dimensions Like 4D Spacetime?
  • · Replies 19 ·
Replies
19
Views
640
I Conventionality of the One-Way Speed of Light
  • · Replies 6 ·
Replies
6
Views
770
B Trying to calculate proper time of worldlines using rotating frames
  • · Replies 35 ·
2
Replies
35
Views
945
A Reconciling units for the Einstein and Landau-Lifshitz pseudotensors
  • · Replies 3 ·
Replies
3
Views
1K
I What Are the Limits of the Universe According to Cosmologists?
  • · Replies 47 ·
2
Replies
47
Views
2K
A Dirac's integral for the energy-momentum of the gravitational field
  • · Replies 38 ·
2
Replies
38
Views
966
Help me understand why “Block Universe” is not scientifically proven
  • · Replies 45 ·
2
Replies
45
Views
5K
B Could we ever create a black hole?
  • · Replies 5 ·
Replies
5
Views
470
I Follow-up Einstein Definition of Simultaneity for Langevin Observers
  • · Replies 4 ·
Replies
4
Views
807
I Symmetry of motion in the special theory of relativity
  • · Replies 37 ·
2
Replies
37
Views
3K
I Hawking After 54 Years Confirmed: BH surfaces don't shrink
  • · Replies 9 ·
Replies
9
Views
510
I A sufficient condition for integrability of equation ##\nabla g=0##
  • · Replies 71 ·
3
Replies
71
Views
2K
I Follow-up on the Expanding Universe Insight article
  • · Replies 2 ·
Replies
2
Views
510
Insights Relativator (Circular Slide-Rule): Simulated with Desmos - Insight
  • · Replies 1 ·
Replies
1
Views
3K
I How do Tensors "work" in relation to linear algebraic objects?
  • · Replies 7 ·
Replies
7
Views
579
I Confused about time dilation -- motion vs energy
  • · Replies 9 ·
Replies
9
Views
695
A 1-Way Speed of Light
  • · Replies 42 ·
2
Replies
42
Views
1K
A Gravitational Analysis of Wide Binaries
  • · Replies 13 ·
Replies
13
Views
528
I Mass conservation in black holes
  • · Replies 8 ·
Replies
8
Views
1K
B How can a black hole absorb matter?
  • · Replies 31 ·
2
Replies
31
Views
1K
I Please explain how length contraction and time dilation result in a constant c
  • · Replies 4 ·
Replies
4
Views
489
I Can this experiment break Lorentz symmetry?
  • · Replies 35 ·
2
Replies
35
Views
942
I MTW exercise 21.26: junction conditions for a thin shell of dust
  • · Replies 5 ·
Replies
5
Views
483
I Eddington’s margin of error
  • · Replies 4 ·
Replies
4
Views
482
B Can frame dragging do this?
  • · Replies 1 ·
Replies
1
Views
399
I Understanding the historical shift away from absolute simultaneity
  • · Replies 25 ·
Replies
25
Views
689
A Is there any topology behind factor 2 in Schwarzschild radius?
  • · Replies 11 ·
Replies
11
Views
497
A Is the constancy of c a postulate or a derivable theorem?
  • · Replies 13 ·
Replies
13
Views
556
I How do non-diagonal indices of a metric allow for local flatness?
  • · Replies 22 ·
Replies
22
Views
730
I Transformation for Lemaitre coordinates
  • · Replies 8 ·
Replies
8
Views
522
B What reference frame is used for the velocity v in the Lorentz transformation?
  • · Replies 53 ·
2
Replies
53
Views
1K
B Oberth Effect Near Sag A*
  • · Replies 35 ·
2
Replies
35
Views
2K
A Error in Landau-Lifshitz Vol 2, equation (2), page 277
  • · Replies 10 ·
Replies
10
Views
652
B Debating the Validity of a Conversion Factor for Mass-Energy Equivalence
  • · Replies 13 ·
Replies
13
Views
656
B Can an expanding EM be quantized: E=mc^2?
  • · Replies 11 ·
Replies
11
Views
548
I Gravitation (MTW) Misner Thorne Wheeler - 50 years (RIP) C.W.Misner
  • · Replies 9 ·
Replies
9
Views
2K
A A global energy conservation law in general relativity
  • · Replies 36 ·
2
Replies
36
Views
1K
I Gravitational lensing of gravitational waves - real?
  • · Replies 3 ·
Replies
3
Views
555
A Uncertainties in the proof of Proposition 4.4.2 in Hawking and Ellis
  • · Replies 2 ·
Replies
2
Views
783
A Weinberg's proof of ##{T^{\mu\nu}}_{,\nu}=0## for a perfect fluid
  • · Replies 2 ·
Replies
2
Views
491
A How do you convert the Pound–Rebka redshift into time variation?
  • · Replies 6 ·
Replies
6
Views
530
B Relativistic contraction factor
  • · Replies 8 ·
Replies
8
Views
818
A Looking for linear frame dragging formula
  • · Replies 3 ·
Replies
3
Views
527
I Freefall and gravity
  • · Replies 10 ·
Replies
10
Views
605
A Dirac's "comprehensive action principle" -- independent equations
  • · Replies 1 ·
Replies
1
Views
492
B Time dilation for two clocks at different altitudes on Earth
  • · Replies 14 ·
Replies
14
Views
959
A Dirac's "GTR" Eq (27.4): how momentum ##p^\mu## varies
  • · Replies 50 ·
2
Replies
50
Views
3K
I How does GR deal with pointlike objects with mass?
  • · Replies 5 ·
Replies
5
Views
559
I Shwartzschild coordinate system
  • · Replies 5 ·
Replies
5
Views
679
I How to calculate basis vectors from metric tensor (as a matrix)?
  • · Replies 6 ·
Replies
6
Views
686
B Can Curved Spacetime Enable Faster-Than-Light Travel?
  • · Replies 12 ·
Replies
12
Views
3K
A Weyl tensor and coordinate acceleration
  • · Replies 12 ·
Replies
12
Views
2K
I With gravitational lensing, which way is down?
  • · Replies 24 ·
Replies
24
Views
880
A The Lagrangian of a free particle ##L=-m \, ds/dt##
  • · Replies 3 ·
Replies
3
Views
727
B Geometric and arithmetic means and contraction factor
  • · Replies 6 ·
Replies
6
Views
627
I Question about a Square Light Clock
  • · Replies 8 ·
Replies
8
Views
812
B Gravity and speed of information for orbiting planets
  • · Replies 22 ·
Replies
22
Views
845
B A question about warp bubbles and navigation
  • · Replies 22 ·
Replies
22
Views
946
A Question about Weinberg's GR book
  • · Replies 5 ·
Replies
5
Views
935
A Singularity Formation and Breakdown Ricci Tensor
  • · Replies 3 ·
Replies
3
Views
668
A The Causal Bootstrap Paradox in General Relativity
  • · Replies 10 ·
Replies
10
Views
874
I Theoretically, can perfectly flat spacetime exist in the Universe?
  • · Replies 31 ·
2
Replies
31
Views
3K
I Why Is the Speed of Light Essential in 4-Velocity Invariance?
  • · Replies 11 ·
Replies
11
Views
1K
A Question on Dirac's derivatives of the 4-velocity w.r.t. coordinates
  • · Replies 53 ·
2
Replies
53
Views
3K
A Sidney Coleman's Lectures on Relativity: New Book by CUP
  • · Replies 5 ·
Replies
5
Views
3K
A Does the New Paper on Singularities Offer Proof of Their Existence?
  • · Replies 6 ·
Replies
6
Views
885
A Tensors in null basis
  • · Replies 9 ·
Replies
9
Views
2K
I Another Time Dilation Question
  • · Replies 23 ·
Replies
23
Views
3K
I ##\epsilon_{ijk}## in terms of ##\delta's##
  • · Replies 3 ·
Replies
3
Views
1K
B Does the gravitational distortion of mass still exist in the past?
  • · Replies 28 ·
Replies
28
Views
1K
I Missing proof of the Shell theorem in General Relativity
  • · Replies 34 ·
2
Replies
34
Views
2K
A A Question on the TOV Limit: Continuous Forces vs. a Discrete Trigger
  • · Replies 10 ·
Replies
10
Views
947