A walkable city has libraries in every alternate neighborhood. So one is generally at most 1~1.5km away. But anything more than ~800m, I'm taking the bus anyway.
Gravity waves detection and cheap solar cells are mind-blowing to me. Gravity waves for just the sensitivity achieved and solar for how rapidly it's improved. It used be a cute technology used in calculators, impossible to match economically turning a generator or directly burning stuff, and now it's the default first choice.
Yeah, figuring out which dependencies in which locations just seemed not worth it