How to Think About Relativity

In Newtonian physics, space and time had their independent identities, and nobody ever got them mixed up. It was with the theory of relativity, put together in the early 20th century, that talking about space-time became almost unavoidable. In relativity, it’s no longer true that space and time have separate, objective meanings. What really exists is space-time, and slicing it up into space and…

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