Before the Time keeping reforms of the Union most member species kept their own time recording methods. Terraused a complicated time system used on Moon and Planet orbits. It was based on different calendars. The Terran Hour was 60 minutes divided into 60 seconds. But smaller time units were based on decimals 1/100 Sec 1/1ooo sec etc. A Day was 24 hrs. And there were 7 days in a week, and 4 weeks in a month. There were 12 Month in a Year and a Year usually was 365 days. It was complicated and quite illogical but since the human biological clock was tuned to these time periods (Especially the Day night cycle and the monthly periods) so human time keeping (OTT) was and is kept on many Human Union Worlds.