Exhibition · Flagship · perspective · spacetime
No Universal Now
Can two observers reverse the order of distant events and both remain physically correct?
What to notice
Opposite-moving observers can assign different time-orderings to sufficiently separated events while causal structure stays fixed. The point is not that “anything goes”; it is that a valid view can depend on the observer without destroying the shared underlying structure.
Everyday analogy. Two people on moving trains can disagree about which of two far-away flashes happened first, even while agreeing on every event where one could actually affect the other.
Pre-rendered from an executable educational relativity model. Public page is static and read-only.