Coherent time

Part of my units pages

The base unit of time in SI is the second, but it’s common for metric to use hours, e.g. kilometres per hour (km/h), where:

1 hour = 60 minutes
       = 60×60 seconds
       = 3600 seconds

This seems like a simple problem of metric having redundant units (like the tonne or hectare), so we should express speeds as metres per second, and so on. However, it’s a bit more complicated since seconds actually measure hours! That makes them a poor choice of base unit.

To resolve this discrepancy, I think it would be a bad idea to simply choose the hour as our base (rather than 1/3600th of an hour). That would either require conversion factors of 3600 all over the place, or require redefinition of almost every other unit.

I think a better approach is to keep these SI units as they are, preserving their conversion factors of 1; but ditch the name “second”, which is derived from the hour and the ordinal “2ⁿᵈ”.

We could shorten the name to “sec”, which is already commonly understood. Its plural “secs” invokes the idea of sixes, and fits nicely into sexagesimal time