The Infinite World

 I am hoping to cross 2000 km mark for the whole year of 2026. This is about 5.48km per day to run. Hopefully I can achieved this target this year and do a sub 5 hours for the scsm 2026 marathon on the first Sunday of 2026

How accurate were human in keeping time before the atomic clock, which came into existence in 1955! If there were a 10 percent off in time keeping, then human could be only in the 1800s now, if their forefathers counted too quickly or we could be in the 2200s if they counted too slowly! How reliable were their forefathers time keeping skills ?