Equation 73 · Part 3 · The Bend an Elevator Cannot Fake

Symbol U

d\tau = U(Z)\,dt

U

What this part means

U is an input to the expression that computes the quantity on the left.

Its job in the formula

U is an input to the expression that computes the quantity on the left.

Full expressionSymbol UArticle meaning

The passage around this formula

This is an exact solution describing flat Minkowski spacetime in non-inertial coordinates, not a weak-field approximation. A clock held static at height Z has d $\tau$ = U(Z)\,dt exactly, so two such clocks compare frequencies as $\nu_2$ / $\nu_1$ = U( $Z_1$ )/U( $Z_2$ ) to all orders — the same exact redshift formula an accelerating rocket produces for light climbing or falling inside it. The node potential is $\phi(Z)$ = $\ln$ U(Z) = $\ln(1 + gZ/c^2)$ , and its first derivative at…

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Learn the underlying idea

A function assigns an output to each allowed input. The expression f(x) means “apply f to x”.

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Sources cited in the article section

[14] General Relativity ↗

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