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For any two points in the event space (spacetime), which are causally disconnected (space-like separated, which means one point is not in the light cone of the
by dandanua 4y ago
For any two points in the event space (spacetime), which are causally disconnected (space-like separated, which means one point is not in the light cone of the other), there is always an observer that perceives them simultaneously. There are also observers for which one point precedes the other and vice versa. There are observers that can't see (or cause) one of the points, or both.
- bambax 4y agoAh, but then it's not especially counterintuitive: causally independent events can happen in any order... The layman's notion of "time" implies causality/irreversibility. Events that have no causal relation between all have their own little timeline, and it's not troubling or surprising to consider that they are simultaneous / that we examine them in a kind of superposition. Or am I saying something stupid? ;-)
- dandanua 4y agoThat's right. We've just learned to believe that there is only a past and a future, where the future is caused by the past. In Special Relativity those are just two light cones, but there are always other events. Though, in a flat spacetime they will affect our future, eventually, because we are moving slower than light. In other words, every event is past to some of our future event. The Big Bang is a different story, because the theory says that spacetime is evolving.