** CE410. [[Physical constants are only assumed constant]].
*** CE411. [[Speed of light has changed]].
**** CE411.1. [[Physicists found that the speed of light was once fasterLos físicos descubrieron que la velocidad de la luz fue una vez más rápida]].
*** CE412. [[Gravitational time dilation made distant clocks run faster]].
*** (see also [[CF210]]: Radiometric dating assumes constant rates.)