# How did they calculate the speed of light?

 P: 12 The modern method for determining the speed of light was developed by K. M. Evenson et al. It relies on separate mesurements of wavelength and frequency emitted by a stabilized laser. They achieved the value c=2 999 792 458 m/s, which has uncertainty of only 1 m/s. Theoretically Maxwell predicted that self-supporting electromagnetic waves must propagate at speed $$c=\frac{1}{\sqrt{\mu_0\epsilon_0}}$$ for more info, check out: http://nvl.nist.gov/pub/nistpubs/sp958-lide/191-193.pdf