What is the Bully Row time system?

Figure 1

The Bully Row time system is neither a clock nor a calendar. Clocks are tied to the rotation of the Earth and measure Universal Time (UT) in terms of days and fractions of days (for example: hours, minutes, and seconds). Calendars are tied to changes in the seasons, which result from the orbit of the Earth around the Sun (Ephemeris time), and from the precession of the equinoxes. Calendars measure time in terms of days, weeks, months, and years. Clocks and calendars are used for tracking biological processes such as setting a time to wake up in the morning or determining when to plant crops. It is essential for clocks and calendars to remain correlated with the earth's actual orientation for proper management of life's biological processes.

Since clocks and calendars are tied to the motion of the Earth, and these motions are somewhat irregular, it becomes necessary from time to time to insert leap seconds, or make other corrections, to keep clocks and calendars in sync with the Earth's actual orientation. As shown in figure 1 above, the Earth's rotational motion (UT) can experience variations on the order of 500 milliseconds per year. The Earth's orbital motion (ET) can experience variations on the order of 40 milliseconds per year. During the 110 year period (1930 AD ... 2040 AD) shown in figure 1, the accumulation of Earth's rotational variations resulted in an increase of Delta T (ET-UT) from less than 25 seconds to more than 70 seconds.

The Bully Row time system (shown on the far right axis in figure 1) is not directly tied to the motions of the Earth, and hence, it is never necessary to insert leap seconds or other corrections into Bully Row timestamps. The Bully Row time system measures elapsed time and can be directly related to International Atomic Time (TAI), which is the passage of elapsed time as measured using atomic clocks.