Light will replace electricity in circuits

We'll need this tech when we're in the PHOTON BELT. Otherwise back to the stone age.

One is absolute; first is comparative. The flow of time varies one location to another location. Hence the term: the law of relativity. Science has shown that there's only one "substance-less substance" that can change into matter. And that's energy. Einstein's famous equation, E=MC2, tells us that energy can change into matter. And once it changes into matter, time grabs hold.
Transporters and replicators (Star Trek) will become a reality. You can see space, you can see matter, you can feel energy, you can see light energy. At lands end, the guild will use guiding light to fold space.