In the 6 minute time keeping lecture, I was surprised that Einstein’s theory of relatively was proven experimentally only a decade ago. Books much older speak of it with such conviction, yet it was not observed yet.
The other fact that surprised me was how arbitrary the number of the days in the month was. Some Roman Caesar thought odd numbers were lucky and made each other month 29 or 31 days? The concept of weeks fit oddly in the 30ish day monthly calendar. These constructs that I didn’t pay attention to shape my life yet were chosen (to a degree) arbitrarily.