The math in his presentation seems to work out if you interpret it as milliseconds (e.g., the day is getting shorter by an average of 2.2 milliseconds every cen

The math in his presentation seems to work out if you interpret it as milliseconds (e.g., the day is getting shorter by an average of 2.2 milliseconds every century). I'm not sure why that particular abbreviation. I tried searching Google to find people using "mts" to refer to milliseconds, and it seems like it could be "millisecond timestamp" or "metric time series"??