Keith Cooper - Time appeared to move 5 times more slowly in 1st billion years after Big Bang, quasar 'clocks' reveal:
https://www.space.com/quasar-clocks-universe-time-dilation
#TimeDilation #Timekeeping #Time #BlackHoles #QuasarClock #Clock #Quasars #Redshift #GeneralRelativity #Relativity #Astrophysics #Cosmology