If you figure out how to make cheap vacuum cables you will probably become very rich.

But otherwise chains of microwave links does get much closer to c in applications where you want absolute lowest latency (or much more commonly, when digging a fiber line is too expensive)

Not vacuum but an inert gas: https://www.thefoa.org/tech/ref/fiber/Hollow-core-fiber.html

> Why can't we use vacuum cables?

Hollow-core fiber is basically this!

> LMGPTTFY

"let me go prompt that for you" or "let me GPT that for you"?