Special Relativity Simulation
At everyday speeds relativity is invisible; near light speed it dominates. This simulation lets you push an object's velocity towards c and watch clocks slow and lengths contract by the predicted factors.
How to use this simulation
- Set the velocity as a fraction of the speed of light
- Compare a moving clock with a stationary one
- Show the contracted length alongside the rest length
What to look for
- Effects are negligible below about 10% of light speed
- Time dilation and length contraction share the same γ factor
- γ climbs steeply as v approaches c, without ever being finite at c
The physics behind it
Because the speed of light is the same for every observer, moving clocks run slow by the Lorentz factor γ = 1/√(1 − v²/c²) and moving lengths contract along the direction of motion by the same factor. At 10% of c the effect is under one percent; at 99% of c, γ is about seven. Nothing with mass can reach c, since γ diverges.