Space vs time: One has to go – but which?
来源：未知 作者：公仪旬 时间：2019-03-13 03:15:13
By Anil Ananthaswamy Video: Why space and time have a secret connection TO ISAAC NEWTON, space was the “sensorium of God”, the organ through which the deity surveyed His creation. It was absolute, unchanging, infinite. Flowing through it “equably without regard to anything external”, as Newton wrote in his great physical treatise Principia, was another similarly absolute heavenly creation: time. Not everyone bought that idea. Newton’s perennial antagonist Gottfried Leibniz was notably sniffy of a God who needed an organ to perceive things, and asked pointedly whether a clockmaker deity would need to “wind up his watch from time to time”. A few centuries on, God features less prominently in the debate, but arguments about the nature of space and time swirl on. Are both basic constituents of reality, or neither – or does one perhaps emerge from the other in some way? We are yet to reach a conclusive answer, but it is becoming clear that if we wish to make further progress in physics, we must. The route to a truly powerful theory of reality passes through an intimate understanding of space and time. (Image: Skizzomat) The search for reality’s building blocks goes to the heart of what physics is about. “When we find the simplest equations for everything in the universe, the fundamental quantities would be what appear in those equations,” says theorist Joe Polchinski of the University of California, Santa Barbara. That makes it all the more embarrassing that the two sets of equations we use to describe the physical world differ so radically in form and content. Einstein’s relativity, which covers gravity,