The speed of light is a tautology. We define it via how many meters light travels in a second. And we define the meter by the same measure. It’s just the distance light travels in 1⁄299792458

This got me thinking if we defined the metre to be a more round number, like 1/300000000.

It would shrink the metre by 0.6918mm.

Now I’m curious about what implications that would have.