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
Undergrad Time Dilation for Photons: Explained
- NODARman
- · Replies 17 ·
Undergrad Cosmic Test Reveals Odd Findings for Einstein's Relativity
- bhobba
- · Replies 4 ·
Undergrad Twin Paradox with accelerated Motion
- Sagittarius A-Star
- · Replies 15 ·
High School How Did Einstein's E=mc² Transform Our Understanding of Inertia and Gravity?
- TrillAeon
- · Replies 40 ·
Undergrad Twin paradox for (accelerated) dummies?
- member 728827
- · Replies 36 ·
Undergrad Calculating Spacetime Around Multiple Objects
- Sciencemaster
- · Replies 7 ·
High School Muon Tomography Evidence for Special Relativity?
- racerunner
- · Replies 14 ·
Graduate Why is Tau-AB^2 not t^2 + x^2?
- BLevine1985
- · Replies 3 ·
Undergrad Anti-symmetric part of an equation
- GR191511
- · Replies 9 ·
Undergrad What Is the Proper Time in Curved Space?
- Kashmir
- · Replies 48 ·
Undergrad Michelson–Morley experiment and the velocity of the ether wind
- Ahmed1029
- · Replies 11 ·
High School Time Shift Reference Point: Earth or Other?
- akmtnrunner
- · Replies 7 ·
Undergrad Create movement from leveraging the propagation of magmatism
- seb7
- · Replies 5 ·
Undergrad Lorentz Contraction & Twin Paradox
- Mickey1
- · Replies 3 ·
Undergrad Einstein's Derivation of Elapsed Time for Remote Comoving Object
- Halc
- · Replies 1 ·
High School Where am I wrong in this travelling faster than light Idea I've had?
- ulrichburke
- · Replies 17 ·
Undergrad Faster-than-Light Causality-Flip: Thought Experiment Reference?
- Mikeal
- · Replies 3 ·
High School Can there be causality when there is spacelike separation?
- entropy1
- · Replies 6 ·
Undergrad The Christoffel symbols at the origin -- Why zero?
- GR191511
- · Replies 44 ·
Undergrad What is Spacelike vs. Timelike Coordinate?
- GR191511
- · Replies 2 ·
Undergrad The invariance of the speed of light is not only a hypothesis?
- zoltrix
- · Replies 57 ·
Undergrad Twin Paradox with radioactive twins
- Kairos
- · Replies 31 ·
High School GTR Vacuum vs Quantum Theory Vacuum: Speed of Light
- Pikkugnome
- · Replies 11 ·
High School Speed of Light in Free Space - Einstein's Second Principle
- abdossamad2003
- · Replies 8 ·
High School Mass & Weight Impact on Spiraling Into a Black Hole
- Hornbein
- · Replies 8 ·
Undergrad Relativistic length contraction
- leonid.ge
- · Replies 2 ·
Undergrad Instantaneous coordinates of an event in space (special relativity)
- Ahmed1029
- · Replies 20 ·
Undergrad Geodesic in Weak Field Limit: Introducing Einstein's Relativity
- GR191511
- · Replies 9 ·
Undergrad Resolving the Twin Paradox: Non-Straight Paths and Proper Time in Space-Time
- Ahmed1029
- · Replies 8 ·
Undergrad Understanding Three Force: Definition and Application
- Kashmir
- · Replies 27 ·
Undergrad Bending of Light Along the Sun: Explaining Half w/ Equivalence Principle
- HansH
- · Replies 15 ·
Undergrad What's the definition of angle in a curved space embedded in a higher Eucledian space?
- Ahmed1029
- · Replies 9 ·
Undergrad Newton's Gravity & Lorentz Contraction: Is Modification Needed?
- Kashmir
- · Replies 15 ·
Undergrad An issue with length contraction
- student34
- · Replies 78 ·
Undergrad Solving for Extrema of Proper Time Integral
- Kashmir
- · Replies 4 ·
Undergrad Black hole horizon for different observers
- shinobi20
- · Replies 24 ·
Undergrad Can Curves Live Out of Embedding Diagrams?
- LCSphysicist
- · Replies 4 ·
High School Grandfather Paradox & Self Consistency Principle: Are They Different?
- BadgerBadger92
- · Replies 18 ·
Undergrad Coordinate and time transformations
- Ahmed1029
- · Replies 5 ·
Undergrad Theory Without Spacelike Separations: Can It Exist?
- Gerenuk
- · Replies 10 ·
High School Time Dilation & Bosons: Decay Rate Changes?
- Andrew Wright
- · Replies 6 ·
Undergrad Does light take longer to go a set distance on a train?
- shawn9521
- · Replies 10 ·
Undergrad Force due to acceleration and time flowing differently
- HansH
- · Replies 167 ·
Graduate Is it possible for variable speed of light in a vacuum?
- kissfire
- · Replies 2 ·
Undergrad Some thoughts about Bell's string paradox alternatives
- member 728827
- · Replies 75 ·
Undergrad Understand 4-Vectors & Spacetime: Hartle Gravity Chapter 5
- Kashmir
- · Replies 4 ·
Undergrad Beginner's Guide to GR: Questions & Answers
- Chenkel
- · Replies 13 ·
Undergrad Connection & Affine Geodesics: Q&A
- GR191511
- · Replies 7 ·
Undergrad Time difference caused by length contraction
- externo
- · Replies 52 ·
Undergrad Geometries from Line Element $$dl^2=d\theta^2 + \sin^2\theta\, d\varphi^2$$
- Demystifier
- · Replies 15 ·
Undergrad Calculation of gravitational redshift in an accelerating elevator
- externo
- · Replies 27 ·
Undergrad Tipler 1976: Clarifying Symbol Meaning
- hawkdron496
- · Replies 13 ·
Undergrad Can we determine the one way speed of light by combined measurements?
- HansH
- · Replies 146 ·
Undergrad Measuring Time & Spatial Distances: Timelike vs Spacelike
- Kashmir
- · Replies 11 ·
High School Problem about postulate of the invariance of the speed of light
- externo
- · Replies 33 ·
Undergrad What Would it Look Like to Fall into a Black Hole?
- Hornbein
- · Replies 19 ·
Graduate Potential Energy of Relativistic Particles in Coulomb Field
- reterty
- · Replies 4 ·
Undergrad Coordinate System Transformation: Lowering/Raising Indices Explained
- GR191511
- · Replies 2 ·
Undergrad When and how can I apply Born rigidity condition?
- member 728827
- · Replies 40 ·
Undergrad What is the definition of proper time interval according to Wikipedia?
- Kashmir
- · Replies 9 ·
Undergrad Trying to understand space-time diagrams
- Kashmir
- · Replies 61 ·
Undergrad Energy of Light in Accelerating Universe: Comparing Cases
- Pony
- · Replies 24 ·
Undergrad Reconciling Lorentz Four-Force Density w/ Spacelike Four-Current (##c = 1##)
- SiennaTheGr8
- · Replies 10 ·
High School Historic question regarding SR and c*t
- Trysse
- · Replies 12 ·
High School Experimental evidence for effective mass increasing with speed
- Bastion
- · Replies 11 ·
Undergrad What, exactly, are invariants?
- Freixas
- · Replies 144 ·
High School Light Taking U-Turn: Transformation of Star to Black Hole
- shivakumar
- · Replies 7 ·
Undergrad Difference Between Lorentz Transformation & Special Relativity
- BadgerBadger92
- · Replies 3 ·
Undergrad Hartle, Gravity pg 34: Question about Time in Non-Inertial Frames
- Kashmir
- · Replies 18 ·
High School Sign of Expansion Scalar in Expanding FLRW Universe
- Onyx
- · Replies 35 ·
High School Gravitational acceleration and sub-atomic electric charge
- rwh2100
- · Replies 12 ·
Undergrad Why are acceleration, jerk, etc not relative, just like velocity?
- Ahmed1029
- · Replies 29 ·
High School Einstein's Twin Paradox: Confusing Solution?
- phymath7
- · Replies 11 ·
Undergrad Carroll GR: Geodesic Eq from Var Principles
- hawkdron496
- · Replies 13 ·
Undergrad Using position of free particle to measure time
- Kashmir
- · Replies 18 ·
Undergrad Equations of Motion for Massless Particle in Potential
- tomdodd4598
- · Replies 15 ·
Undergrad Def Proper Time GR: Half or Integral Along Path?
- hawkdron496
- · Replies 17 ·
Graduate Can a Null Surface Satisfy the Requirements for a Cauchy Surface?
- PeterDonis
- · Replies 13 ·
Graduate What is the formal definition of spacetime in physics?
- Enrico
- · Replies 61 ·
Undergrad Coord Transform in de Sitter Space: Phys Significance &Linearity?
- Sciencemaster
- · Replies 5 ·
Undergrad Richard Feynman: Deriving Lorentz Mass Transformation
- 43arcsec
- · Replies 9 ·
Undergrad Appearance of Warp Bubble Internal Volume to Distant Observer
- Onyx
- · Replies 37 ·
Undergrad Carroll GR: Tangent Space & Partial Derivatives
- chartery
- · Replies 7 ·
Graduate What does G mean in general relativity?
- Feynstein100
- · Replies 55 ·
Graduate Computing Thomas Precession: Part 2 | Francesco
- Coelum
- · Replies 7 ·
Graduate Computing the Thomas Precession: Help from PFers Needed!
- Coelum
- · Replies 1 ·
High School Does the CMB give us absolute space and time in practice?
- S Holtom
- · Replies 70 ·
High School (ELI5) why can’t massless particles travel infinitely fast?
- balls
- · Replies 17 ·
Undergrad Michelson-Morley: Errors in Calculations?
- vchal
- · Replies 6 ·
Undergrad Wormholes & Warp Drives: Can Circular Polarizers Create Them?
- sddfds
- · Replies 12 ·
Undergrad Calculate Contraction 2nd & 4th Indices Riemann Tensor
- GR191511
- · Replies 24 ·
High School Does Force Travel Faster Than Light?
- MrSimp
- · Replies 8 ·
High School General Relativity & Grav. Time Dilation Qn
- IXWELL
- · Replies 2 ·
Undergrad Matter Gaining Energy from Expanding Spacetime?
- Suekdccia
- · Replies 7 ·
Undergrad Difference Between Locally Flat & Locally Inertial?
- GR191511
- · Replies 33 ·
Undergrad Does Special and General Relativity Affect Aging of Apollo Astronauts?
- PeterDonis
- · Replies 10 ·
High School Gravitational Potential Energy & Mass Change: Andrew's Question
- andrew s 1905
- · Replies 4 ·
Undergrad Calculate Gaussian Curvature from 4D Metric Tensor
- Sciencemaster
- · Replies 14 ·
High School High Frequency Photons: More Mass, More Bend?
- mdeng
- · Replies 10 ·
Undergrad Cosmic Inflation Explained: Constant Velocity of Electromagnetic Radiation
- JonathanMFreedman
- · Replies 3 ·