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.
I Twin paradox for (accelerated) dummies?
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I Calculating Spacetime Around Multiple Objects
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B Muon Tomography Evidence for Special Relativity?
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A Why is Tau-AB^2 not t^2 + x^2?
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I Anti-symmetric part of an equation
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I What Is the Proper Time in Curved Space?
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I Michelson–Morley experiment and the velocity of the ether wind
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B Time Shift Reference Point: Earth or Other?
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I Create movement from leveraging the propagation of magmatism
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I Lorentz Contraction & Twin Paradox
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I Einstein's Derivation of Elapsed Time for Remote Comoving Object
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I Faster-than-Light Causality-Flip: Thought Experiment Reference?
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B Can there be causality when there is spacelike separation?
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I The Christoffel symbols at the origin -- Why zero?
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I What is Spacelike vs. Timelike Coordinate?
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I The invariance of the speed of light is not only a hypothesis?
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I Twin Paradox with radioactive twins
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B GTR Vacuum vs Quantum Theory Vacuum: Speed of Light
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B Speed of Light in Free Space - Einstein's Second Principle
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B Mass & Weight Impact on Spiraling Into a Black Hole
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I Relativistic length contraction
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I Instantaneous coordinates of an event in space (special relativity)
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I Geodesic in Weak Field Limit: Introducing Einstein's Relativity
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I Resolving the Twin Paradox: Non-Straight Paths and Proper Time in Space-Time
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I Understanding Three Force: Definition and Application
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I Bending of Light Along the Sun: Explaining Half w/ Equivalence Principle
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I What's the definition of angle in a curved space embedded in a higher Eucledian space?
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I Newton's Gravity & Lorentz Contraction: Is Modification Needed?
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I An issue with length contraction
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I Solving for Extrema of Proper Time Integral
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I Black hole horizon for different observers
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I Can Curves Live Out of Embedding Diagrams?
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B Grandfather Paradox & Self Consistency Principle: Are They Different?
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I Coordinate and time transformations
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I Theory Without Spacelike Separations: Can It Exist?
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B Time Dilation & Bosons: Decay Rate Changes?
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I Does light take longer to go a set distance on a train?
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I Force due to acceleration and time flowing differently
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A Is it possible for variable speed of light in a vacuum?
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I Some thoughts about Bell's string paradox alternatives
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I Understand 4-Vectors & Spacetime: Hartle Gravity Chapter 5
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I Beginner's Guide to GR: Questions & Answers
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I Connection & Affine Geodesics: Q&A
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I Time difference caused by length contraction
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I Geometries from Line Element $$dl^2=d\theta^2 + \sin^2\theta\, d\varphi^2$$
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I Calculation of gravitational redshift in an accelerating elevator
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I Tipler 1976: Clarifying Symbol Meaning
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I Can we determine the one way speed of light by combined measurements?
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I Measuring Time & Spatial Distances: Timelike vs Spacelike
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B Problem about postulate of the invariance of the speed of light
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I What Would it Look Like to Fall into a Black Hole?
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A Potential Energy of Relativistic Particles in Coulomb Field
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I Coordinate System Transformation: Lowering/Raising Indices Explained
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I When and how can I apply Born rigidity condition?
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I What is the definition of proper time interval according to Wikipedia?
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I Trying to understand space-time diagrams
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I Energy of Light in Accelerating Universe: Comparing Cases
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I Reconciling Lorentz Four-Force Density w/ Spacelike Four-Current (##c = 1##)
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B Historic question regarding SR and c*t
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B Experimental evidence for effective mass increasing with speed
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I What, exactly, are invariants?
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B Light Taking U-Turn: Transformation of Star to Black Hole
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I Difference Between Lorentz Transformation & Special Relativity
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I Hartle, Gravity pg 34: Question about Time in Non-Inertial Frames
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B Sign of Expansion Scalar in Expanding FLRW Universe
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I Why are acceleration, jerk, etc not relative, just like velocity?
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B Einstein's Twin Paradox: Confusing Solution?
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I Carroll GR: Geodesic Eq from Var Principles
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I Using position of free particle to measure time
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I Equations of Motion for Massless Particle in Potential
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I Def Proper Time GR: Half or Integral Along Path?
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A Can a Null Surface Satisfy the Requirements for a Cauchy Surface?
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A What is the formal definition of spacetime in physics?
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I Coord Transform in de Sitter Space: Phys Significance &Linearity?
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I Richard Feynman: Deriving Lorentz Mass Transformation
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I Appearance of Warp Bubble Internal Volume to Distant Observer
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I Carroll GR: Tangent Space & Partial Derivatives
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What does G mean in general relativity?
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A Computing Thomas Precession: Part 2 | Francesco
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A Computing the Thomas Precession: Help from PFers Needed!
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B Does the CMB give us absolute space and time in practice?
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B (ELI5) why can’t massless particles travel infinitely fast?
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I Michelson-Morley: Errors in Calculations?
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I Wormholes & Warp Drives: Can Circular Polarizers Create Them?
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I Calculate Contraction 2nd & 4th Indices Riemann Tensor
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B Does Force Travel Faster Than Light?
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B General Relativity & Grav. Time Dilation Qn
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I Matter Gaining Energy from Expanding Spacetime?
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I Difference Between Locally Flat & Locally Inertial?
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I Does Special and General Relativity Affect Aging of Apollo Astronauts?
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B Gravitational Potential Energy & Mass Change: Andrew's Question
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I Calculate Gaussian Curvature from 4D Metric Tensor
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B High Frequency Photons: More Mass, More Bend?
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I Cosmic Inflation Explained: Constant Velocity of Electromagnetic Radiation
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A Relativistic Relative Velocity Comp.: Bini, D. et al. (1995)
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B Differences in Predictions between SR and LR?
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I Spacetime interval and basic properties of light
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A Can discrete temporal symmetries exist in general relativity?
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I Understanding Simultaneity Through Male & Female Clocks Meeting
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I Karl Schwarzschild: Solving GR on the Eastern Front
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