So far we’ve seen how the speed of light postulate leads to time dilation and length contraction, but we’ve only scratched the surface of the implications of special relativity.

For example, momentum and energy. Momentum, $p=mv$, and kinetic energy, $K=\frac{1}{2}m{v}^2$, are both conserved quantities in Newtonian mechanics. Pay close attention and you’ll see that both of these quantities depend on the velocity of the object—relativity will affect these quantities too!

This rabbit hole goes deep, eventually leading to the classic $E=m{c}^2$ equation and more, but we’ll only cover the fundamentals and specific applications of relativity that relate to timekeeping and navigation in deep space.