Special Theory of Relativity

Talks about the universality of the speed of light (time is not absolute) The value for speed of light is the same in all inertial frames of reference. Space and time can no longer be treated separately. Spacetime interval $\Delta s^2=-c^2\Delta t^2+\Delta {\vec{x}}^2$ We set c=1. $d{s}^2={\eta }_{\mu \nu }d{x}^{\mu }d{x}^{\nu }$ where η is theMinkowski Metric. #Lorentz transformation is linear such that $x^{\prime \mu }={\Lambda }_{\nu }^{\mu }{x}^{\nu }$ Note that the coordinates are arbitrary and hence physics is invariant (Lorentz Invariance).

1. Light Cone
2. Proper Length
3. Proper Time