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.
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FAQ: Experimental Basis of Special Relativity
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Insights When Discussing the Twin Paradox: Read This First
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Insights Maxwell’s Equations in a Static, Spherically Symmetric Spacetime
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Insights An Introduction to the Generation of Mass from Energy
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Relativity Insights: FAQs on Photons, Gravity, Time Dilation, and More!
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I Why Do Events Freeze For Me at the Speed of Light?
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I Euclidean geometry and gravity
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I Relativity of simultaneity in actuality
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B Reciprocal time dilation
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B Photon Energy Without Rest Mass – How?
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I The wave equation interpretation of special relativity
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A Is the variation of the metric ##\delta g_{\mu\nu}## a tensor?
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I Synchronizing clocks at different locations to measure speed of light
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I Convention for writing $\binom{1}{1}$ tensors in matrix form?
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I Synchronizing clocks in an inertial frame if light is anisotropic
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I An invariant while crossing the horizon
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I I don't see how a black hole's event horizon can be crossed
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I Variation of the lightning train thought experiment
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B Project GRE^2AT - GR on Mt. Ranier
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I How Is Intrinsic Curvature Measured in Higher Dimensions Like 4D Spacetime?
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I Conventionality of the One-Way Speed of Light
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B Trying to calculate proper time of worldlines using rotating frames
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I Question about Parallel Transport
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A Reconciling units for the Einstein and Landau-Lifshitz pseudotensors
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I What Are the Limits of the Universe According to Cosmologists?
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A Dirac's integral for the energy-momentum of the gravitational field
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B Could we ever create a black hole?
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I Follow-up Einstein Definition of Simultaneity for Langevin Observers
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I Symmetry of motion in the special theory of relativity
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I Hawking After 54 Years Confirmed: BH surfaces don't shrink
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I A sufficient condition for integrability of equation ##\nabla g=0##
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I 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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I How do Tensors "work" in relation to linear algebraic objects?
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I Confused about time dilation -- motion vs energy
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A 1-Way Speed of Light
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A Gravitational Analysis of Wide Binaries
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I Mass conservation in black holes
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B How can a black hole absorb matter?
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I Please explain how length contraction and time dilation result in a constant c
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I Can this experiment break Lorentz symmetry?
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I MTW exercise 21.26: junction conditions for a thin shell of dust
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I Eddington’s margin of error
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B Can frame dragging do this?
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I Understanding the historical shift away from absolute simultaneity
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A Is there any topology behind factor 2 in Schwarzschild radius?
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A Is the constancy of c a postulate or a derivable theorem?
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I How do non-diagonal indices of a metric allow for local flatness?
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I Transformation for Lemaitre coordinates
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B What reference frame is used for the velocity v in the Lorentz transformation?
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B Oberth Effect Near Sag A*
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A Error in Landau-Lifshitz Vol 2, equation (2), page 277
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B Debating the Validity of a Conversion Factor for Mass-Energy Equivalence
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B Can an expanding EM be quantized: E=mc^2?
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I Gravitation (MTW) Misner Thorne Wheeler - 50 years (RIP) C.W.Misner
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A A global energy conservation law in general relativity
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I Gravitational lensing of gravitational waves - real?
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A Uncertainties in the proof of Proposition 4.4.2 in Hawking and Ellis
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A Weinberg's proof of ##{T^{\mu\nu}}_{,\nu}=0## for a perfect fluid
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A How do you convert the Pound–Rebka redshift into time variation?
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B Relativistic contraction factor
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A Looking for linear frame dragging formula
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I Freefall and gravity
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A Dirac's "comprehensive action principle" -- independent equations
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B Time dilation for two clocks at different altitudes on Earth
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A Dirac's "GTR" Eq (27.4): how momentum ##p^\mu## varies
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I How does GR deal with pointlike objects with mass?
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I Shwartzschild coordinate system
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I How to calculate basis vectors from metric tensor (as a matrix)?
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B Can Curved Spacetime Enable Faster-Than-Light Travel?
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A Weyl tensor and coordinate acceleration
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I With gravitational lensing, which way is down?
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A The Lagrangian of a free particle ##L=-m \, ds/dt##
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B Geometric and arithmetic means and contraction factor
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I Question about a Square Light Clock
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B Gravity and speed of information for orbiting planets
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B A question about warp bubbles and navigation
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A Question about Weinberg's GR book
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A Singularity Formation and Breakdown Ricci Tensor
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A The Causal Bootstrap Paradox in General Relativity
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I Theoretically, can perfectly flat spacetime exist in the Universe?
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I Why Is the Speed of Light Essential in 4-Velocity Invariance?
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A Question on Dirac's derivatives of the 4-velocity w.r.t. coordinates
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A Sidney Coleman's Lectures on Relativity: New Book by CUP
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A Does the New Paper on Singularities Offer Proof of Their Existence?
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A Tensors in null basis
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I Another Time Dilation Question
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I ##\epsilon_{ijk}## in terms of ##\delta's##
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B Does the gravitational distortion of mass still exist in the past?
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A A Question on the TOV Limit: Continuous Forces vs. a Discrete Trigger
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I Effect of Radiation Pressure on a Moving Object
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A Does the EP imply that a free-falling observer follows a geodesic?
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I Temporal length vs. Temporal displacement
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A Covariant form of Maxwell's (inhomogeneous) equations (in GR)
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A Error in Landau-Lifshitz Vol 2, Fig. 20, page 310
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A "TImescape" models
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B Mass of a gyroscope when rotating or not rotating
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B A photon always travels in a black hole
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I Going Up-Down Elevator G-forces vs Bouncing off a Spring G-force
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B Michelson Morley experiment and the Doppler effect
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B Relativity and Biological Aging: How Time Dilation Slows Cell Activity
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B An issue about the twin paradox
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Relativity

The theory of relativity, formulated by Albert Einstein, comprises two fundamental theories—special and general relativity. Special relativity, proposed in 1905, redefines our understanding of space and time by asserting the constancy of the speed of light for all observers and introducing concepts like time dilation and length contraction.

General relativity, presented in 1915, extends these principles to incorporate gravity. It describes gravity as the curvature of spacetime caused by massive objects, leading to phenomena like gravitational time dilation and the prediction of black holes. Einstein's equations have been consistently validated through experiments and observations, profoundly influencing our comprehension of the universe's fabric and dynamics.

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