How has time dilation been experimentally confirmed?

1. Time dilation predicts that a moving clock should record less elapsed time than a clock at rest. 2. This was tested by sending an atomic clock into orbit and comparing its recorded time with a clock that stayed on Earth. 3. GPS satellites also must be adjusted to compensate for this same effect to give accurate positioning. 4. Weighing a clock, photographing it, or checking its color are not how this effect was tested. 5. So the orbiting atomic clock comparison is correct. _Source: OpenStax Physics (CC BY 4.0), Ch 10 "Special Relativity", section 10.2 Consequences of Special Relativity_