From Tony Watkins, Oldbury, West Midlands, UK
Time isn’t an illusion or mystery, and we don’t need an arcane physics theory to explain why it flows in only one direction. At sub-atomic to intergalactic scales, all matter is in motion relative to most other matter, as described by Isaac Newton’s laws of motion, making future motion and events predictable (31 January, p 28).
Since antiquity, humans have found it useful to measure and divide the intervals between recurring natural events such as day and night, phases of the moon, tides and annual seasons, and these measurements have become formalised by the development of calendars, sundials, clocks, etc. The choice of which recurring events to use for time measurement is an arbitrary one, so, although time and change due to relative motion are real, time measurement as we experience it is a human invention.
