Physics
Special Relativity
Space and time are not separate stages but one woven fabric. Boost to a moving frame and its axes skew: clocks run slow, rulers shrink, and events that looked simultaneous no longer are. Only the speed of light, the 45° cone, stays fixed for everyone.
Lorentz factor γ1.000
Event (lab)—
Event (moving)—
Horizontal is space, vertical is time (ct). The indigo mesh is the moving observer's grid of space and time. Drag the white event to read its coordinates in both frames.
What to observe
- As β grows, the moving observer's time axis (ct′) and space axis (x′)scissor toward the light cone from opposite sides, but the 45° cone itself never moves: light has the same speed for everyone.
- Put the event on the moving x′ axis (its "now"). In the lab that same instant sits at a different height, a different time. Simultaneity isrelative.
- One tick up the ct′ axis is one second for the moving clock, yet it reacheshigher than one lab-second (time dilation, γ > 1), while a moving ruler measures shorter (length contraction). Same fabric, different slices.
Shortcuts: space run/pause · s step · r reset · f fullscreen