For ten points, name this phenomenon in which clocks move slower in reference frames moving quickly with respect to an observer.
Hefele and Keating measured this phenomenon using airplanes, finding that the non-reciprocal type had a greater effect. The simpler form of this effect is proportional to the Lorentz factor; from this form arises the so-called twin paradox. This effect fundamentally arises because simultaneity is frame- dependent is relativity. For ten points, name this phenomenon in which clocks move slower in reference frames moving quickly with respect to an observer.
Hefele and Keating measured this phenomenon using airplanes, finding that the non-reciprocal type had a greater effect.
{time dilation} (or {time dilatation})