26.12 Spacetime Diagrams

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In a spacetime diagram, how do you see that observers in relative motion will all agree that the speed of light is constant?

In a spacetime diagram, how do you see that if two events are spacelike separated – so have no causal connection – then different observers can disagree regarding which event happened first?

In class you showed how the relativity of simultaneity appears in spacetime diagrams. Can you reason the other way around—namely, derive the relativity of simultaneity from spacetime diagrams?