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 Does the Euclidean distance on a spacetime diagram have physical meaning?
- Kairos
- · Replies 16 ·
Undergrad Do AEST (Absolute Euclidean Spacetime) models work?
- name123
- · Replies 83 ·
Undergrad Hawking Radiation Extrapolation: A Conjecture
- Mike Holland
- · Replies 1 ·
Undergrad Hawking Radiation: Can Particles Appear with Relativistic Velocities?
- Mike Holland
- · Replies 4 ·
Graduate Causal loops and closed timelike curves in general relativity
- PreposterousUniverse
- · Replies 10 ·
Undergrad Graphical derivation of length contraction using light clocks in Minkowski spacetime
- Tomas Vencl
- · Replies 6 ·
High School Doppler Shifting of Light: Simplification or Reality?
- pforeman
- · Replies 6 ·
Undergrad Does gravitational potential or field strength cause time dilation?
- Green dwarf
- · Replies 12 ·
Undergrad What would an observer inside a collapsing shell see?
- blademan9999
- · Replies 2 ·
High School Principle of Relativity: Classical Physics Example
- abdossamad2003
- · Replies 3 ·
High School Can Bob measure Alice's proper time using his accelerated frame metric?
- member 728827
- · Replies 29 ·
High School Gravity Between Two Stars 45 Billion Light Years Away?
- NODARman
- · Replies 5 ·
Undergrad Why does the time dilation formula break down for photons?
- NODARman
- · Replies 17 ·
Undergrad Scientists tested relativity on cosmic scales: why is this important?
- 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 Can Lorentz contraction alone construct the twin paradox?
- Mickey1
- · Replies 3 ·
Undergrad Einstein's Derivation of Elapsed Time for Remote Comoving Object
- Halc
- · Replies 1 ·
High School Why can't relativistic mass energy be used as thrust to exceed light speed?
- 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 Difference between GTR vacuum and quantum theory vacuum
- Pikkugnome
- · Replies 11 ·
High School Speed of Light in Free Space - Einstein's Second Principle
- abdossamad2003
- · Replies 8 ·
High School Does mass affect how fast an object spirals into a black hole?
- Hornbein
- · Replies 8 ·
Undergrad Do length-contracted rods burn faster and contracted clocks run slower?
- 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 Is the three force definition equivalent to Newtonian force?
- Kashmir
- · Replies 27 ·
Undergrad Why does the equivalence principle only explain half the light bending by the sun?
- HansH
- · Replies 15 ·
Undergrad What's the definition of angle in a curved space embedded in a higher Eucledian space?
- Ahmed1029
- · Replies 9 ·
Undergrad Does Lorentz contraction force Newton's gravity to be modified?
- 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 Are the grandfather paradox and self consistency principle different?
- BadgerBadger92
- · Replies 18 ·
Undergrad Coordinate and time transformations
- Ahmed1029
- · Replies 5 ·
Undergrad Can a theory exclude spacelike separated events?
- Gerenuk
- · Replies 10 ·
High School Can time dilation change boson decay rates in material?
- 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 Are 4-vectors coordinate-independent like 3-vectors?
- Kashmir
- · Replies 4 ·
Undergrad How does GR explain orbits by warping spacetime instead of applying force?
- Chenkel
- · Replies 13 ·
Undergrad Does the connection vanish along an affine geodesic?
- 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 Symbol meaning in Tipler's 1976 causality violation paper
- hawkdron496
- · Replies 13 ·
Undergrad Can we determine the one way speed of light by combined measurements?
- HansH
- · Replies 146 ·
Undergrad Why do clocks measure timelike distances, not timelike time?
- 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 Relationship between index lowering/raising and coordinate transformations
- 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 How does the cosmological constant affect light energy between distant observers?
- 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 Does relativistic mass increase with speed or is it just momentum?
- 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 How do Lorentz transformations relate to special relativity?
- BadgerBadger92
- · Replies 3 ·
Undergrad Does Newtonian mechanics assume the same time for all 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 Why does acceleration break symmetry in the twin paradox?
- phymath7
- · Replies 11 ·
Undergrad Why can we vary a fixed normalization constant in Carroll's geodesic derivation?
- 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 Why is proper time the integral of dτ and not half that?
- 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 Coordinate transformations in de Sitter space using the invariant line element
- 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 Why does d/dλ(f) equal d/dλ(f∘γ) in Carroll's tangent space derivation?
- chartery
- · Replies 7 ·
Graduate What does G mean in general relativity?
- Feynstein100
- · Replies 55 ·
Graduate Thomas precession derivation discrepancy in Goldstein
- Coelum
- · Replies 7 ·
Graduate Thomas precession derivation in Goldstein equation 7.19
- 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 ·