Proper Time
The physical time interval measured by a clock moving along a specific worldline through spacetime.
Governing formula
dτ = dt / γ = √(dt² - dx²/c²)
SI unit
Seconds (Proper Time τ)
In depth
Proper time τ is a relativistic scalar invariant independent of coordinate frame. It represents the actual aging experienced by an observer along their worldline through Minkowski or Riemannian spacetime.
Examples in the real world
Measuring the shorter proper time elapsed on a relativistic astronaut's watch compared to coordinate time elapsed on Earth.