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 Can anyone clarify the relativistic twin paradox for me?
  • Curious Kev
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Graduate Calculating geodesic equation from Hamiltonian in presence of EM
  • Jokar
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Undergrad Why does laser beam hit the same target when fired?
  • jt128
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Undergrad Lorentz transformation on mode functions
  • Haorong Wu
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Undergrad A six-vector is related to a 2nd rank antisymmetric tensor in Minkowski Spacetime?
  • grzz
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Undergrad Is the weak field limit valid for the Brans-Dicke scalar field?
  • p78653
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Undergrad Robert B. Laughlin (Physics Nobel Laureate, Stanford University)
  • Tony Yuan
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Undergrad What about the Big Ben Paradox?
  • patdolan
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Undergrad Using 4-derivative
  • deuteron
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High School Special relativity thought: Traveling to the future relative to a particle
  • L Drago
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High School Imaginary distance is nonsense
  • AndreyN
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High School c^2 in Einstein‘s theory of relativity
  • Lightisslow
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Graduate Special Relativity in Rotating Reference frame
  • Jokar
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Undergrad A question about the speed of light and electromagnetism
  • johnfrancismurray
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Undergrad The Lorentz factor gamma and proper time
  • Trysse
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Undergrad Can the intersection point of two light beams exceed the speed of light?
  • lloydziegler
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Undergrad Need opinions on Youtube video: "From constant moving charge to SR"
  • TCO
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Undergrad A thought experiment on simultaneity
  • member 743765
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Undergrad Speed of Light & Bullet
  • FRANKENSTEIN54
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Undergrad Question about length contraction and repulsive force
  • Junhyoung Park
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Undergrad A matter of time dilation: how much time has actually passed?
  • bbbl67
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Graduate Different time coordinates due to different velocities
  • Timothy S.
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Graduate Can We Flatten Space with York Decomposition?
  • DBailen
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High School Question about the Entropy of a Black Hole Singularity
  • ShadowX5452
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High School But how does something start moving?
  • Line_112
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High School Events vs Effect of Events in Relativity of Simultaneity
  • Timbo65
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Undergrad Speed of light one more time
  • Rick16
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Undergrad Principal and Gaussian curvature of the FRW metric
  • shinobi20
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High School How does Einstein's equation work? Why do we need to square c?
  • ineed2know
  • · Replies 18 ·
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Insights Addition of Velocities (Velocity Composition) in Special Relativity
  • robphy
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Undergrad Physical Difference Between Co- and Contravariant Vectors
  • deuteron
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High School Let me ask a thing about the Speed of Light
  • Azar525
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Undergrad Co- and Contravariance
  • deuteron
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Undergrad Determining a stationary point of reference to base all absolute motion
  • tsslieberman
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High School Crossing the Bekenstein Bound at Black Hole Event Horizon
  • .Scott
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Undergrad Relativity and a Mirror
  • saddlestone-man
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Undergrad Validity of Birkhoff's theorem in flat Minkowski spacetime
  • Volterra
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High School Challenging the notion of "crossing" a black hole's event horizon
  • euquila
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Undergrad Follow-up on Index notation for inverse Lorentz transform
  • cianfa72
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Undergrad Canonical energy momentum tensor: Quick question
  • binbagsss
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Undergrad Embedding Diagram of Weyl Metric in ##R^3##
  • Onyx
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Undergrad Higgs Field & GR: Are They Related or Not?
  • Dennis Plews
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High School Calculating Time taken to reach speed with Time Dilation
  • TheStick
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Undergrad How does an arbitrary choice of the origin affect real observations?
  • larpal
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Undergrad Asteroid hits static black hole
  • timmdeeg
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Graduate Overall perturbation for two free-falling particles in flat spacetime
  • TimWilliams87
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Undergrad Does everything move at the speed of light?
  • Max364
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High School What is the relationship between speed and time dilation in special relativity?
  • L Drago
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Undergrad How Can Tensors Be Evaluated to Scalars?
  • LarryS
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High School Pole-barn paradox, one question
  • FIL
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High School Is Time Travel Possible Near Black Holes?
  • L Drago
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High School What Are Closed Timelike Curves and Common Misunderstandings About Them?
  • L Drago
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High School What is the essence of the ladder paradox in relativity?
  • L Drago
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Undergrad Researchers calculate how much faster time passes on the Moon
  • pinball1970
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High School How far away can a World So Newly Born Be at relativistic velocities?
  • DaveC426913
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High School Speed of light seen by a moving observer
  • Speady
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Graduate Show Lagrangian is invariant under a Lorentz transformation without using generators
  • binbagsss
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Graduate Kerr to Schwarzschild to white transition
  • javisot20
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Undergrad Proof of Lorentz transformation
  • murshiddreamengineer
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Undergrad Questions about a thought experiment involving time dilation
  • Muzaz
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Undergrad Is Measuring the One-Way Speed of Light Possible Near a Black Hole?
  • FranzS
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Undergrad Black hole and singularity
  • Ranku
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Graduate What kind of topology change does this Lorentzian metric describe?
  • Onyx
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Undergrad General relativity question: Gravity clock
  • logicalmorality
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Undergrad Formulating the Poincare group and its double cover
  • redtree
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High School Why Does the Speed of Light Max Out at 186,282 Miles Per Second?
  • thetexan
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Undergrad Geodesics in Schwarzschild: Reparametrizing the Equations
  • Hunterc2429
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High School Very simple exercises in General Relativity
  • DaTario
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Undergrad On the possibility of exploding a black hole
  • DaTario
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Undergrad Basic questions about E=mc^2 energy conversion
  • Tldrknhndsm
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Undergrad Do black holes have magnetic fields?
  • Feynstein100
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Undergrad SR-time dilation vs GR-time dilation on rotating Earth
  • cianfa72
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Undergrad Affine parameter and non-geodesic null curves
  • JimWhoKnew
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Undergrad Where is the mistake in this derivation of Length Contraction?
  • aliinuur
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Graduate Energy-to-angular momentum ratio in EM v. gravity quadrupole radiation
  • Kostik
  • · Replies 0 ·
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Graduate Quadrupole radiation formula for gravity
  • Kostik
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Undergrad Special relativity & Synchronization of clocks
  • noxurxo
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Undergrad Frame fields and congruences of worldlines
  • cianfa72
  • · Replies 24 ·
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Undergrad Lorentz invariance of the 4-momentum
  • redtree
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High School Would an object in orbit change facing or orientation?
  • sbaker8688
  • · Replies 23 ·
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Graduate A very peculiar emergent definition of gravity
  • arivero
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Undergrad The uniqueness of D=4
  • arivero
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Undergrad Why do objects follow a geodesic?
  • Zayan
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Undergrad Increase in surface charge density in different frames of reference
  • lys04
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High School General relativity and frame of reference
  • south
  • · Replies 12 ·
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Undergrad Line element in Kerr coordinates at singularity
  • chartery
  • · Replies 20 ·
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Undergrad Trying to Fully Understand Mass Increase of Unstable Bonds
  • Ascendant0
  • · Replies 8 ·
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Undergrad Help understanding proof of ds=ds' in Classical Theory of Fields
  • tx_kurt
  • · Replies 10 ·
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High School Nalini Joshi's Time Travel Ideas
  • Tomwh98
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Undergrad Constants of motion symmetric spacetimes
  • cianfa72
  • · Replies 9 ·
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Undergrad Speed of information-carrying radiation
  • Speady
  • · Replies 9 ·
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Graduate Zeroth law of black hole thermodynamics
  • Antarres
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Undergrad Is Spacetime a Real Physical Entity or Merely a Conceptual Framework in Physics?
  • Michael Ray Mooney
  • · Replies 4 ·
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Undergrad Quaternions and Special Relativity
  • grzz
  • · Replies 20 ·
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Undergrad Escape velocity near a black hole: Newtonian or Special Relativity?
  • Trollfaz
  • · Replies 17 ·
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Undergrad Circumnavigating the Universe in Cosmos (1980)
  • bob012345
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Undergrad Definition of time-independent scalar field in GR
  • Clvrhammer
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Undergrad Congruence of curves in spacetime
  • cianfa72
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Undergrad Distance between two light pulses
  • member 743765
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Graduate Timelike curves on event horizon
  • Antarres
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