In special relativity, length dilation is defined as follows:(adsbygoogle = window.adsbygoogle || []).push({});

X' = X0√(1 - V2/c2), where X' is the apparent/dilated length and X0 is the "proper length"

Therefore proper length: X0 = X'/√(1 - V2/c2), where c > V > -c

I read a book on the spacetime approach to relativity using the relationship: S = √(ct)2 - X2 for ct > X and: S = √X2 - (ct)2 - for X > ct

The spacetime approach produces the same results as special relativity, with the exception of "proper length" which it defines as X0 = X'√(1 - c2/V2) where ∞ > V > c and -c > V > -∞

In all other cases including time dilation, proper time, energy and momentum relationships etc., the spacetime and special relativity equations agree.

What is the physical significance of the different results in the proper distance relationships?

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# Spacetime/Proper Length

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