SPACE · MOTION · GRAVITY

Time Observatory

Two clocks. Different journeys through time.

Gravity changes the paceGENERAL RELATIVITY

A · REFERENCE

Far-away clock

0.00 s

Elapsed time on clock A

B · EXPERIMENT

Hovering clock

0.00 s

Elapsed time on clock B

CLOCK B FALLS BEHIND

0 s

Accumulated clock difference

CHANGE THE CONDITIONS

Approach the horizon

Distance from the center 3.00 rₛ

Near horizonFarther away

Clock B's rate relative to A

Playback speed

Playback follows clock A. Changing the experiment or conditions resets both clocks.

After one day on clock A

WHAT YOU ARE SEEING

Equations & model notes

Clocks always tick normally for someone beside them. These are comparisons of elapsed time, with signal travel delays excluded. The scenes are diagrams; the numerical clock rates use the equations above.

Learn more: Schwarzschild geometry · JILA · Moving clocks · UT Austin · Clock experiments · NIST