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.
Undergrad How Is Intrinsic Curvature Measured in Higher Dimensions Like 4D Spacetime?
  • · Replies 19 ·
Replies
19
Views
2K
Undergrad Conventionality of the One-Way Speed of Light
  • · Replies 6 ·
Replies
6
Views
2K
High School Trying to calculate proper time of worldlines using rotating frames
  • · Replies 35 ·
2
Replies
35
Views
3K
Graduate Reconciling units for the Einstein and Landau-Lifshitz pseudotensors
  • · Replies 3 ·
Replies
3
Views
2K
Undergrad What Are the Limits of the Universe According to Cosmologists?
  • · Replies 47 ·
2
Replies
47
Views
4K
Graduate Dirac's integral for the energy-momentum of the gravitational field
  • · Replies 38 ·
2
Replies
38
Views
3K
Graduate Help me understand why “Block Universe” is not scientifically proven
  • · Replies 45 ·
2
Replies
45
Views
11K
High School Could we ever create a black hole?
  • · Replies 5 ·
Replies
5
Views
1K
Undergrad Follow-up Einstein Definition of Simultaneity for Langevin Observers
  • · Replies 3 ·
Replies
3
Views
2K
Undergrad Symmetry of motion in the special theory of relativity
  • · Replies 37 ·
2
Replies
37
Views
5K
Undergrad Hawking After 54 Years Confirmed: BH surfaces don't shrink
  • · Replies 9 ·
Replies
9
Views
1K
Undergrad A sufficient condition for integrability of equation ##\nabla g=0##
  • · Replies 71 ·
3
Replies
71
Views
4K
Undergrad Follow-up on the Expanding Universe Insight article
  • · Replies 2 ·
Replies
2
Views
1K
Insights Relativator (Circular Slide-Rule): Simulated with Desmos - Insight
  • · Replies 1 ·
Replies
1
Views
7K
Undergrad How do Tensors "work" in relation to linear algebraic objects?
  • · Replies 7 ·
Replies
7
Views
2K
Undergrad Confused about time dilation -- motion vs energy
  • · Replies 9 ·
Replies
9
Views
2K
Graduate 1-Way Speed of Light
  • · Replies 42 ·
2
Replies
42
Views
3K
Graduate Gravitational Analysis of Wide Binaries
  • · Replies 13 ·
Replies
13
Views
1K
Undergrad Mass conservation in black holes
  • · Replies 8 ·
Replies
8
Views
2K
High School How can a black hole absorb matter?
  • · Replies 31 ·
2
Replies
31
Views
3K
Undergrad Please explain how length contraction and time dilation result in a constant c
  • · Replies 4 ·
Replies
4
Views
1K
Undergrad Can this experiment break Lorentz symmetry?
  • · Replies 35 ·
2
Replies
35
Views
2K
Undergrad MTW exercise 21.26: junction conditions for a thin shell of dust
  • · Replies 5 ·
Replies
5
Views
1K
Undergrad Eddington’s margin of error
  • · Replies 4 ·
Replies
4
Views
1K
High School Can frame dragging do this?
  • · Replies 1 ·
Replies
1
Views
922
Undergrad Understanding the historical shift away from absolute simultaneity
  • · Replies 25 ·
Replies
25
Views
2K
Graduate Is there any topology behind factor 2 in Schwarzschild radius?
  • · Replies 11 ·
Replies
11
Views
1K
Graduate Is the constancy of c a postulate or a derivable theorem?
  • · Replies 13 ·
Replies
13
Views
1K
Undergrad How do non-diagonal indices of a metric allow for local flatness?
  • · Replies 22 ·
Replies
22
Views
2K
Undergrad Transformation for Lemaitre coordinates
  • · Replies 8 ·
Replies
8
Views
1K
High School What reference frame is used for the velocity v in the Lorentz transformation?
  • · Replies 53 ·
2
Replies
53
Views
3K
High School Oberth Effect Near Sag A*
  • · Replies 35 ·
2
Replies
35
Views
3K
Graduate Error in Landau-Lifshitz Vol 2, equation (2), page 277
  • · Replies 10 ·
Replies
10
Views
1K
High School Debating the Validity of a Conversion Factor for Mass-Energy Equivalence
  • · Replies 13 ·
Replies
13
Views
1K
High School Can an expanding EM be quantized: E=mc^2?
  • · Replies 11 ·
Replies
11
Views
995
Undergrad Gravitation (MTW) Misner Thorne Wheeler - 50 years (RIP) C.W.Misner
  • · Replies 9 ·
Replies
9
Views
2K
High School Conservation of kinetic energy in expanding space
  • · Replies 25 ·
Replies
25
Views
2K
Graduate A global energy conservation law in general relativity
  • · Replies 36 ·
2
Replies
36
Views
3K
Undergrad Gravitational lensing of gravitational waves - real?
  • · Replies 3 ·
Replies
3
Views
1K
Graduate Uncertainties in the proof of Proposition 4.4.2 in Hawking and Ellis
  • · Replies 2 ·
Replies
2
Views
1K
Graduate Weinberg's proof of ##{T^{\mu\nu}}_{,\nu}=0## for a perfect fluid
  • · Replies 2 ·
Replies
2
Views
1K
Graduate How do you convert the Pound–Rebka redshift into time variation?
  • · Replies 6 ·
Replies
6
Views
1K
High School Relativistic contraction factor
  • · Replies 8 ·
Replies
8
Views
1K
Graduate Looking for linear frame dragging formula
  • · Replies 3 ·
Replies
3
Views
1K
Undergrad Freefall and gravity
  • · Replies 10 ·
Replies
10
Views
1K
Graduate Dirac's "comprehensive action principle" -- independent equations
  • · Replies 1 ·
Replies
1
Views
1K
High School Time dilation for two clocks at different altitudes on Earth
  • · Replies 14 ·
Replies
14
Views
2K
Graduate Dirac's "GTR" Eq (27.4): how momentum ##p^\mu## varies
  • · Replies 50 ·
2
Replies
50
Views
4K
Undergrad How does GR deal with pointlike objects with mass?
  • · Replies 5 ·
Replies
5
Views
1K
Undergrad Shwartzschild coordinate system
  • · Replies 5 ·
Replies
5
Views
1K
Undergrad How to calculate basis vectors from metric tensor (as a matrix)?
  • · Replies 6 ·
Replies
6
Views
1K
High School Can Curved Spacetime Enable Faster-Than-Light Travel?
  • · Replies 12 ·
Replies
12
Views
4K
Graduate Weyl tensor and coordinate acceleration
  • · Replies 12 ·
Replies
12
Views
3K
High School Geometric and arithmetic means and contraction factor
  • · Replies 6 ·
Replies
6
Views
996
Undergrad Question about a Square Light Clock
  • · Replies 8 ·
Replies
8
Views
1K
High School Gravity and speed of information for orbiting planets
  • · Replies 22 ·
Replies
22
Views
1K
High School A question about warp bubbles and navigation
  • · Replies 22 ·
Replies
22
Views
2K
Graduate Question about Weinberg's GR book
  • · Replies 5 ·
Replies
5
Views
1K
Graduate Singularity Formation and Breakdown Ricci Tensor
  • · Replies 3 ·
Replies
3
Views
966
Graduate The Causal Bootstrap Paradox in General Relativity
  • · Replies 10 ·
Replies
10
Views
1K
Undergrad Theoretically, can perfectly flat spacetime exist in the Universe?
  • · Replies 31 ·
2
Replies
31
Views
3K
Undergrad Reframing Light Bending Using Density Instead of Radius
  • · Replies 20 ·
Replies
20
Views
1K
Undergrad Why Is the Speed of Light Essential in 4-Velocity Invariance?
  • · Replies 11 ·
Replies
11
Views
2K
Undergrad Intuitive look at bending of light by gravity
  • · Replies 25 ·
Replies
25
Views
2K
Undergrad A "continous" gravitational field formula r=0 to infinity
  • · Replies 16 ·
Replies
16
Views
2K
Graduate Question on Dirac's derivatives of the 4-velocity w.r.t. coordinates
  • · Replies 53 ·
2
Replies
53
Views
4K
Graduate Sidney Coleman's Lectures on Relativity: New Book by CUP
  • · Replies 5 ·
Replies
5
Views
4K
Graduate Does the New Paper on Singularities Offer Proof of Their Existence?
  • · Replies 6 ·
Replies
6
Views
1K
Graduate Tensors in null basis
  • · Replies 9 ·
Replies
9
Views
2K
Undergrad ##\epsilon_{ijk}## in terms of ##\delta's##
  • · Replies 3 ·
Replies
3
Views
2K
High School Does the gravitational distortion of mass still exist in the past?
  • · Replies 28 ·
Replies
28
Views
2K
Undergrad Missing proof of the Shell theorem in General Relativity
  • · Replies 34 ·
2
Replies
34
Views
2K
Graduate A Question on the TOV Limit: Continuous Forces vs. a Discrete Trigger
  • · Replies 10 ·
Replies
10
Views
1K
Undergrad Effect of Radiation Pressure on a Moving Object
  • · Replies 31 ·
2
Replies
31
Views
2K
Graduate Does the EP imply that a free-falling observer follows a geodesic?
  • · Replies 3 ·
Replies
3
Views
1K
Undergrad Temporal length vs. Temporal displacement
  • · Replies 10 ·
Replies
10
Views
2K
Graduate Covariant form of Maxwell's (inhomogeneous) equations (in GR)
  • · Replies 9 ·
Replies
9
Views
1K
Graduate Error in Landau-Lifshitz Vol 2, Fig. 20, page 310
  • · Replies 7 ·
Replies
7
Views
1K
Graduate "TImescape" models
  • · Replies 5 ·
Replies
5
Views
1K
High School Mass of a gyroscope when rotating or not rotating
  • · Replies 13 ·
Replies
13
Views
1K
High School A photon always travels in a black hole
  • · Replies 9 ·
Replies
9
Views
2K
Undergrad Going Up-Down Elevator G-forces vs Bouncing off a Spring G-force
  • · Replies 5 ·
Replies
5
Views
963
High School Michelson Morley experiment and the Doppler effect
  • · Replies 21 ·
Replies
21
Views
2K
Undergrad A thought about visualizing space-time
  • · Replies 24 ·
Replies
24
Views
2K
High School Relativity and Biological Aging: How Time Dilation Slows Cell Activity
  • · Replies 14 ·
Replies
14
Views
3K
Graduate Minimal property of Spacelike geodesics in GR/curved spacetime?
  • · Replies 76 ·
3
Replies
76
Views
4K
High School An issue about the twin paradox
  • · Replies 24 ·
Replies
24
Views
2K
High School Can mass/energy simply be distorted spacetime?
  • · Replies 9 ·
Replies
9
Views
1K
Undergrad Principle of relativity in the proof of invariance of interval
  • · Replies 53 ·
2
Replies
53
Views
6K
Undergrad Why are we looking for a graviton?
  • · Replies 16 ·
Replies
16
Views
2K
Undergrad Epstein diagrams and a traveling ship
  • · Replies 17 ·
Replies
17
Views
1K
Graduate Ricci tensor for Fermi normal coordinates
  • · Replies 1 ·
Replies
1
Views
1K
High School Time Travel: Is it Physically Possible? | Scientific American
  • · Replies 13 ·
Replies
13
Views
4K
Undergrad Question about geometrical engineering (placeholder name)
  • · Replies 32 ·
2
Replies
32
Views
3K
Graduate "Looks" of gravitational wave emissions for an eclipsing ternary compact object?
  • · Replies 1 ·
Replies
1
Views
1K
Graduate Is parallel transport exactly norm-preserving or only approximately?
  • · Replies 21 ·
Replies
21
Views
1K
High School No object actually approaches the speed of light
  • · Replies 9 ·
Replies
9
Views
2K
Undergrad What does g00 element of the Schwarzschild metric tensor tell us?
  • · Replies 28 ·
Replies
28
Views
1K
High School Can anything work (including human brains) inside a black hole?
  • · Replies 22 ·
Replies
22
Views
2K
Undergrad Integral subbundle of 6 KVFs gives a spacetime foliation by 3d hypersurfaces
  • · Replies 22 ·
Replies
22
Views
2K