General relativity · Gravity as geometry
Predict firstWill two identical clocks accumulate the same time?
Connect gravitational clock differences, bent light and tidal stretching to one spacetime geometry.
Prerequisites: A clock measures elapsed time; light carries energy; free fall means no supporting force. No tensor calculus is needed.Gravity changes more than a path
Predict firstWill two identical clocks accumulate the same time?
General relativity treats gravity as the geometry of space and time. A clock measures its own elapsed time, called proper time. Place two identical clocks at fixed distances from this non-rotating black hole and start the comparison at coordinate time zero. Play: the nearer clock completes fewer illuminated cycles. Its mechanism is not broken; the two locations accumulate different proper times between the chosen start and end slices. The small thrusters matter: holding position here requires acceleration.
How to observe
- Compare stationary clocks; follow gravitational redshift through pulse colour and spacing.
- Change the incoming offset and find the boundary between escape and capture.
- Follow a freely falling cloud; learn curvature through stretching and squeezing.
Model notes
Uncharged, non-rotating Schwarzschild exterior. Stationary clocks; numerical null geodesics; analytic small-separation tides along E = 1 radial free fall. Coordinate views are not telescope images. Instruments, packets and beads are enlarged teaching markers. No accretion, spin, gravitational waves or elastic fracture.