Suppose we put a [flashing] clock at the … and we put another identical clock at the … the second flash travels the shorter distance … It is a shorter distance because the ship … You can see, then, that if the two … a separation somewhat less than one second … But now let's think of the rocket ship … they must if [Einstein's] principle of equivalence [between gravity and accelerating frames of reference] is right. … [p. 42-11] For instance, for an altitude difference of … However, just such a change has recently been … [ref].
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