what is the most interesting theory you’ve seen about space and why?

Question: what is the most interesting theory you've seen about space and why?
- Keywords:
  interesting,
  space,
  theory
Asked by ever1demo to Martin M, divyareshmithottungalravy, christinaschoettler on 16 Jun 2025.
- Martin McCoustra answered on 16 Jun 2025:
  
  One of the fun ideas out there is that certain solutions of Einstein’s General Relativity allow us to travel in time. I don’t just mean forward in time as you might expect by going faster and faster, but back in time. Someone even designed a machine to do this… https://en.wikipedia.org/wiki/Tipler_cylinder … Problem is we can’t build it!

Question: what is the most interesting theory you've seen about space and why?