One can use the Principle of Extremal Aging to calculate the path of a freely moving body (in an inertial frame not subject to any forces) in spacetime, curved or flat. Why extremal? Why not just maximal? All the examples I know of involve maximum proper time for a freely moving body. For example the twin paradox. The earth is the freely moving body and the stay at home twin ages the maximum (ignore gravitational time dilation).(adsbygoogle = window.adsbygoogle || []).push({});

Can anyone give me an example of minimal aging and explain the circumstances a freely moving body experiences this? How does minimal aging occur?

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# Why extremal aging, not just maximal? (for an inertial body in spacetime)

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