Scientists estimated a standard period or “tick” of a quasar and then observed quasars up to 12 billion light years away at an earlier era of the universe to calculate that time progressed at 1/5 the rate it does now, due to time dilation.
Detection of the cosmological time dilation of high-redshift quasars, Nature Astronomy (2023) www.nature.com/articles/s41550-023-02029-2
Spaceman84 0 points 10 months ago
Special ed class