3 ms·Another alternate wording: 247 zs is the geometric mean of t_P and 13.1 days.by SilasX 6y agoAnother alternate wording: 247 zs is the geometric mean of t_P and 13.1 days.waheoo 6y agoPlanck time, 247 zeptoseconds, and 13.1days are equally far apart on log scale. Planck time is really small.pwr22 6y agoThanks, I can understand this one :P