Special and General Relativity Forum

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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 A sufficient condition for integrability of equation ##\nabla g=0##
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Undergrad Follow-up on the Expanding Universe Insight article
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Insights Relativator (Circular Slide-Rule): Simulated with Desmos - Insight
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Undergrad How do Tensors "work" in relation to linear algebraic objects?
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Undergrad Confused about time dilation -- motion vs energy
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Graduate 1-Way Speed of Light
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Graduate Gravitational Analysis of Wide Binaries
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Undergrad Mass conservation in black holes
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High School How can a black hole absorb matter?
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Undergrad Please explain how length contraction and time dilation result in a constant c
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Undergrad Can this experiment break Lorentz symmetry?
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Undergrad MTW exercise 21.26: junction conditions for a thin shell of dust
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Undergrad Eddington’s margin of error
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High School Can frame dragging do this?
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Undergrad Understanding the historical shift away from absolute simultaneity
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Graduate Is there any topology behind factor 2 in Schwarzschild radius?
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Graduate Is the constancy of c a postulate or a derivable theorem?
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Undergrad How do non-diagonal indices of a metric allow for local flatness?
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Undergrad Transformation for Lemaitre coordinates
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High School What reference frame is used for the velocity v in the Lorentz transformation?
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High School Oberth Effect Near Sag A*
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Graduate Error in Landau-Lifshitz Vol 2, equation (2), page 277
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High School Debating the Validity of a Conversion Factor for Mass-Energy Equivalence
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High School Can an expanding EM be quantized: E=mc^2?
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Undergrad Gravitation (MTW) Misner Thorne Wheeler - 50 years (RIP) C.W.Misner
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High School Conservation of kinetic energy in expanding space
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Graduate A global energy conservation law in general relativity
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Undergrad Gravitational lensing of gravitational waves - real?
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Graduate Uncertainties in the proof of Proposition 4.4.2 in Hawking and Ellis
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Graduate Weinberg's proof of ##{T^{\mu\nu}}_{,\nu}=0## for a perfect fluid
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Graduate How do you convert the Pound–Rebka redshift into time variation?
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High School Relativistic contraction factor
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Graduate Looking for linear frame dragging formula
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Undergrad Freefall and gravity
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Graduate Dirac's "comprehensive action principle" -- independent equations
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High School Time dilation for two clocks at different altitudes on Earth
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Graduate Dirac's "GTR" Eq (27.4): how momentum ##p^\mu## varies
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Undergrad How does GR deal with pointlike objects with mass?
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Undergrad Shwartzschild coordinate system
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Undergrad How to calculate basis vectors from metric tensor (as a matrix)?
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High School Can Curved Spacetime Enable Faster-Than-Light Travel?
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Graduate Weyl tensor and coordinate acceleration
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Graduate The Lagrangian of a free particle ##L=-m \, ds/dt##
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High School Geometric and arithmetic means and contraction factor
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Undergrad Question about a Square Light Clock
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High School Gravity and speed of information for orbiting planets
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High School A question about warp bubbles and navigation
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Graduate Question about Weinberg's GR book
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Graduate Singularity Formation and Breakdown Ricci Tensor
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Graduate The Causal Bootstrap Paradox in General Relativity
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Undergrad Theoretically, can perfectly flat spacetime exist in the Universe?
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Undergrad Reframing Light Bending Using Density Instead of Radius
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Undergrad Why Is the Speed of Light Essential in 4-Velocity Invariance?
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Undergrad Intuitive look at bending of light by gravity
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Undergrad A "continous" gravitational field formula r=0 to infinity
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Graduate Question on Dirac's derivatives of the 4-velocity w.r.t. coordinates
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Graduate Sidney Coleman's Lectures on Relativity: New Book by CUP
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Graduate Does the New Paper on Singularities Offer Proof of Their Existence?
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Graduate Tensors in null basis
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Undergrad ##\epsilon_{ijk}## in terms of ##\delta's##
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High School Does the gravitational distortion of mass still exist in the past?
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Undergrad Missing proof of the Shell theorem in General Relativity
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Graduate A Question on the TOV Limit: Continuous Forces vs. a Discrete Trigger
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Undergrad Effect of Radiation Pressure on a Moving Object
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Graduate Does the EP imply that a free-falling observer follows a geodesic?
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Undergrad Temporal length vs. Temporal displacement
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Graduate Covariant form of Maxwell's (inhomogeneous) equations (in GR)
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Graduate Error in Landau-Lifshitz Vol 2, Fig. 20, page 310
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Graduate "TImescape" models
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High School Mass of a gyroscope when rotating or not rotating
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High School A photon always travels in a black hole
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Undergrad Going Up-Down Elevator G-forces vs Bouncing off a Spring G-force
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High School Michelson Morley experiment and the Doppler effect
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Undergrad A thought about visualizing space-time
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High School Relativity and Biological Aging: How Time Dilation Slows Cell Activity
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Graduate Minimal property of Spacelike geodesics in GR/curved spacetime?
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High School An issue about the twin paradox
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High School Can mass/energy simply be distorted spacetime?
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Undergrad Principle of relativity in the proof of invariance of interval
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Undergrad Why are we looking for a graviton?
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Undergrad Epstein diagrams and a traveling ship
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High School Lorentz Transformation of Electric & Magnetic Fields Visualized
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Graduate Ricci tensor for Fermi normal coordinates
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High School Time Travel: Is it Physically Possible? | Scientific American
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Undergrad Question about geometrical engineering (placeholder name)
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Graduate "Looks" of gravitational wave emissions for an eclipsing ternary compact object?
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Graduate Is parallel transport exactly norm-preserving or only approximately?
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High School No object actually approaches the speed of light
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Undergrad What does g00 element of the Schwarzschild metric tensor tell us?
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High School Can anything work (including human brains) inside a black hole?
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Undergrad Integral subbundle of 6 KVFs gives a spacetime foliation by 3d hypersurfaces
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Undergrad A textbook passage describing coordinate lines in physical space
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High School When I jump up and down what is the Einsteinian way to describe it?
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Undergrad Twin Paradox Resolution
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Undergrad Notion of parallel worldlines in curved geometry
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High School Question about “Inertia arises from interaction with the Universe’s mass”
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Graduate Landau-Lifshitz pseudotensor - expressing the EM tensor ##T^{ik}##
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High School Space travel and time dilation
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Undergrad Where is the mass in a black hole?
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Undergrad Can light be reflected in a black hole?
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