The 'twin paradox' shows us what it really means for time to be relative - Space.com

What goes for moving clocks goes for everything else; physics, chemistry and biology all operate at a slower pace in moving frames of reference.

Einstein's theory of special relativity teaches us that time is relative. But what does it mean for time to be relative? How can we live in a universe where nobody can agree on when events start, whe… [+5276 chars]

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