Special and General Relativity Forum

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.

Threads

High School Flat spacetime in a gravity well

  • DaveC426913
  • · Replies 40 ·
2
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40

Undergrad Geodesic Maximality: Answers to Relativists' Questions

  • Umaxo
  • · Replies 2 ·
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2

High School Distance Expansion When Moving Away from an Object?

  • Karagoz
  • · Replies 4 ·
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4

High School How can the speed of light be constant for all observers?

  • Karagoz
  • · Replies 15 ·
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15

Undergrad Does Rest Mass Change if c Varies?

  • jocarren
  • · Replies 4 ·
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4

High School How do we know the LIGO gravitational waves came from 1.5 billion light years away?

  • Andrew Washington
  • · Replies 7 ·
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7

High School Speed of Light: Does It Change?

  • Lunct
  • · Replies 3 ·
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3

Graduate Math of Reference Frames: Spanning Vector Space

  • kent davidge
  • · Replies 2 ·
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2

Undergrad Why does the train woman see lightning simultaneously in her frame?

  • taenyfan
  • · Replies 136 ·
5
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136

High School Length contraction applet - have they got it wrong?

  • FranzDiCoccio
  • · Replies 25 ·
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25

High School What speed and direction are we actually traveling?

  • Amazingly Andrew
  • · Replies 60 ·
3
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60

High School How can I derive the law of composition of velocities?

  • AhmedHesham
  • · Replies 14 ·
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14

Graduate Who Was Right - Poincare, Einstein or Neither

  • bhobba
  • · Replies 42 ·
2
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42

Undergrad Lorentz Transformation Matrix: Tensor of Order 2?

  • Ben Geoffrey
  • · Replies 5 ·
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5

Undergrad Some geometry questions re Schwarzschild metric

  • Buzz Bloom
  • · Replies 13 ·
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13

High School Mass and Time Dilation: Causes and Effects

  • fishin_kitten
  • · Replies 7 ·
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7

Graduate Why is Riemannian geometry essential for general relativity?

  • binbagsss
  • · Replies 3 ·
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3

Graduate Prove 2-D Lorentzian Metric is Locally Equivalent to Standard Form

  • Pentaquark5
  • · Replies 9 ·
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9

High School Why can't light travel faster than c?

  • Aarav
  • · Replies 52 ·
2
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52

Undergrad How does Hawking radiation cause a black hole to lose energy?

  • arlesterc
  • · Replies 34 ·
2
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34

Undergrad Theory of Acceleration: Is There a Limit?

  • ObjectivelyRational
  • · Replies 8 ·
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8

Undergrad Find Solutions to Helical Worldline's Surfaces of Simultaneity

  • Pencilvester
  • · Replies 6 ·
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6

Undergrad Weight of a relativistic particle

  • superdave
  • · Replies 83 ·
3
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83

Undergrad Why is the conservation of electric charge expressed in the continuity equation?

  • Tom Evans
  • · Replies 13 ·
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13

Graduate Does the covariant derivative commute with D/ds for a vector field?

  • Pentaquark6
  • · Replies 5 ·
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5

High School Why does Newton's gravity formula work if spacetime curvature replaces gravity?

  • Osvaldo
  • · Replies 5 ·
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5

Undergrad Delta Notation in GR: Replacing vs Raising/Lowering

  • binbagsss
  • · Replies 2 ·
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2

Undergrad De Sitter Universe: Divergent Parallel Lines?

  • dagmar
  • · Replies 3 ·
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3

Undergrad Light From Black Holes: GR vs QM

  • kent davidge
  • · Replies 4 ·
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4

Undergrad Event Horizons - Holographic Principle

  • .Scott
  • · Replies 20 ·
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20

High School Lag of a clock coming back to its initial position (Twins Paradox)

  • Aleberto69
  • · Replies 44 ·
2
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44
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6

Undergrad Latest Gamma Ray Burst Experimental results

  • Azurite
  • · Replies 49 ·
2
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49

Undergrad Does Einstein's elevator analogy correctly explain gravitational light bending?

  • LSMOG
  • · Replies 10 ·
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10

Undergrad What do experimentalists measure: dx or adx in the FLRW metric?

  • exmarine
  • · Replies 10 ·
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10

Undergrad Black hole event horizon confusion

  • mattjbr2
  • · Replies 57 ·
2
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57

High School Why does gravity bend light instead of attracting it?

  • Rigel84
  • · Replies 11 ·
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11

High School Why do we Experience a 'Flow' of Time?

  • TheQuestionGuy14
  • · Replies 106 ·
4
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106

High School What causes the acceleration in the equivalence of gravity and mass?

  • jordankonisky
  • · Replies 4 ·
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4

Undergrad Deflection of Starlight by Newtonian Gravity - Example Calculation

  • Henri Garcia
  • · Replies 2 ·
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2

Graduate Two Dimensional Ricci curvature

  • craigthone
  • · Replies 6 ·
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6

Graduate Prove EL Geodesic and Covariant Geodesic Defs are Same via Riemmanian Geometry

  • binbagsss
  • · Replies 6 ·
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6

High School Velocity of light and absolute rest

  • shivakumarvv75
  • · Replies 27 ·
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27

High School Is the time dimension more fundamental?

  • thermia
  • · Replies 34 ·
2
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34

Graduate Understanding E-Field Transformation in Feynman II_26

  • Verne42
  • · Replies 12 ·
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12

Undergrad How can General Relativity explain the Moon drifting apart from Earth

  • DLeuPel
  • · Replies 6 ·
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6

Graduate Schwarzschild Derivation: Sean Carroll Notes - Theorem Name?

  • binbagsss
  • · Replies 1 ·
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1

Undergrad Understanding Length Contraction: What is Limit of Vanishing Transport Velocity?

  • Philip Dhingra
  • · Replies 6 ·
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6

Undergrad Thermodynamics of Black Holes: Analyzing Carnot Cycles

  • PeteSampras
  • · Replies 1 ·
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1

Undergrad Are spherically symmetric and isotropic the same

  • binbagsss
  • · Replies 9 ·
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9

Graduate Lense-Thirring effect - General Relativity

  • Pentaquark5
  • · Replies 12 ·
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12

Graduate Constant along a geodesic vs covariantly constant

  • binbagsss
  • · Replies 3 ·
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3

High School Light (not) escaping from black holes

  • Outhouse
  • · Replies 53 ·
2
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53

High School Proving Proper Time of Photon in Friedman Metric

  • exmarine
  • · Replies 2 ·
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2

High School Can time travel to the past violate causality in general relativity?

  • TheQuestionGuy14
  • · Replies 30 ·
2
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30

Undergrad FRW metric constraints from isotropy and homogeneity

  • binbagsss
  • · Replies 7 ·
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7

High School Can a spinning spacecraft be ejected to near-light speed?

  • kolleamm
  • · Replies 15 ·
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15

High School If you condense an atom, would it make a black hole?

  • Carobouy
  • · Replies 7 ·
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7

Graduate Why Scalar Quantities Matter in Singularity Tests

  • binbagsss
  • · Replies 5 ·
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5

Undergrad Transforming to Local Inertial Coordinates

  • Ibix
  • · Replies 5 ·
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5

Undergrad Demonstration of relation between geodesics and FLRW metric

  • fab13
  • · Replies 3 ·
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3

Undergrad Why do nuclei have mass defect but nucleons don't?

  • Gene Naden
  • · Replies 9 ·
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9

High School Relative speed and time dilation

  • dayalanand roy
  • · Replies 34 ·
2
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34

High School How Does the Twin Paradox Affect Aging?

  • Daniepie
  • · Replies 44 ·
2
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44

Undergrad Gravity Inside and Outside a Moving Lift

  • Sandeep T S
  • · Replies 9 ·
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9

Undergrad Angular Velocity: Can a Body Move Faster Than C?

  • Sandeep T S
  • · Replies 6 ·
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6

Undergrad Communicating with Black Hole Time Warp: A to B and Back Again

  • RajatX
  • · Replies 2 ·
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2

Undergrad Is the Scientific American Article on the Twin Paradox Accurate?

  • Sorcerer
  • · Replies 7 ·
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7

High School Rest Frame in GTR: What Is It?

  • Sandeep T S
  • · Replies 3 ·
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3

Graduate Inverse of infinitesimal Lorentz transformation

  • Gene Naden
  • · Replies 5 ·
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5

Undergrad Why does the energy-momentum relation apply only to free particles?

  • Parcival
  • · Replies 10 ·
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10

Undergrad Derivation of E=mc2 from Four-Vector Definitions in Special Relativity

  • Ziang
  • · Replies 85 ·
3
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85

High School Einstein's Lift Experiment: The Principle of Equivalence

  • Sandeep T S
  • · Replies 1 ·
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1

Graduate The inverse of spacetime curvature?

  • LilPhysics
  • · Replies 12 ·
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12

Undergrad Feynman II, equation 26.11, off by a factor

  • learn.steadfast
  • · Replies 13 ·
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13

Graduate Alcubierre Drive Direction: How Does Craft Move?

  • Davephaelon
  • · Replies 4 ·
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4

Undergrad Space Contraction: Does Moving Frame Affect Observation?

  • rahaverhma
  • · Replies 6 ·
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6

Undergrad Contravariant first index, covariant on second, Vice versa?

  • Gene Naden
  • · Replies 36 ·
2
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36

Undergrad Using Black Holes to Time Travel Into the Future

  • stevendaryl
  • · Replies 56 ·
2
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56

High School Photons, mass, and black holes

  • Philbert1893
  • · Replies 26 ·
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26

High School Does Light Phase Change During Travel?

  • Bob Dylan
  • · Replies 14 ·
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14

Undergrad Derivatives of EM Four-Potential: Euler-Lagrange to $\nabla \times B$

  • Gene Naden
  • · Replies 3 ·
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3

Graduate Is Gravity a Gauge Theory? A Review of GR and Standard Model Symmetries

  • bhobba
  • · Replies 17 ·
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17

Undergrad Derivation notation with capital D?

  • Emil_M
  • · Replies 5 ·
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5

Undergrad Sum Maxwell Lagrangian 1st Term: Use Minus Signs?

  • Gene Naden
  • · Replies 7 ·
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7

Graduate Interpretation of covariant derivative of a vector field

  • Pentaquark5
  • · Replies 2 ·
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2

High School Curvature: Intrinsic vs. Extrinsic - What's the Difference?

  • vibhuav
  • · Replies 9 ·
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9

Undergrad Why do we need a theory to replace the Galilian composition of velocities?

  • AhmedHesham
  • · Replies 16 ·
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16

Graduate Euler-Lagrange Equations: EM Field Term

  • Gene Naden
  • · Replies 2 ·
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2

Undergrad Spatial curvature in Schwarzschild coordinates near Earth

  • andrewkirk
  • · Replies 3 ·
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3

Undergrad Why does the Lorentz transformation of time depend on relative speed?

  • AhmedHesham
  • · Replies 5 ·
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5

Graduate SR/GRs Views on QM/QFT | Physics Forums

  • VIctor Medvil
  • · Replies 3 ·
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3

Undergrad Relativistic Effect on Object Accelerated to 10000-10000m/s^2

  • sfsssfefsfe
  • · Replies 7 ·
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7

Undergrad How does a smooth rotating object drag spacetime?

  • bland
  • · Replies 6 ·
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6

High School Curvature of space vs. curvature of spacetime

  • Buckethead
  • · Replies 52 ·
2
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52

Undergrad Deriving Divergence Formula in General Relativity

  • Pencilvester
  • · Replies 4 ·
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4

Graduate Solving Schwarzschild Field Equations in this Form

  • bolbteppa
  • · Replies 3 ·
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3

High School Inertial and gravitational mass

  • Geo
  • · Replies 28 ·
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28

Undergrad Can distant stars orbit Earth faster than light in general relativity?

  • JohnNemo
  • · Replies 193 ·
7
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193

Undergrad Interstellar Travel Without Propulsion or Time Dilation

  • Yemmy
  • · Replies 11 ·
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11