Physics Formula For Time

Fun With Physics: It's About Time - For A Change

What Is Time? Time is, IMHO, an illusion. Time has no real independent existence - it can't stand by itself. If you removed all the matter and energy from the Universe, would there be left anything we could address as time? Time is just our way of keeping track of, and measuring rate of change in matter and/or energy. If nothing ever changed it would be nonsense to talk about time. The flow of time; the arrow of time; is just the flow of macro things changing. If everything were somehow 'frozen in time' - like a single frame from a film - then there is no actual time that can be discussed or measured. So we don't in any sense measure something that is time, we measure rate of change and call that time.

Actually you measure rate of change by another rate of change. For example, the rate of change from birth to death is usually measured by the rate of change in position of the Earth orbiting the Sun (years and fractions of years) and rate of change of position of the Earth rotating around on its axis (days and fractions of days). Another example: The rate of change between the beginning of your lunch hour and the ending of your lunch hour is usually measured by the rate of change of the hands of a clock (sixty 360 degree sweeps of the minute hand or a 30 degrees clockwise change in the hour hand) or the rate of change in the numbers on your digital watch, say from 1:00 to 2:00. Translated, a variable or uncertain rate of change (lifespan; length of a lunch 'hour') is usually measured by a standard, invariable, predictable rate of change.

Now rate of change is affected by gravity - a function of mass - the greater the mass the greater the gravity and the slower things change from A to B in that gravitational field, but that slowness is only relative to someone else also measuring A to B but who is in a lesser gravitational field. A clock at the top of a tall building (lesser gravity being further from Earth's centre) ticks at a faster rate than an identical clock at street level (which has higher gravity due to being closer to Earth's centre). Rate of change is also affected by velocity. The faster you go, the slower things change from A to B, again however it's relative to someone else also measuring A to B but who is moving at a lower velocity relative to you. That's why it's the theory of relativity! The standard example is the twin paradox - if your identical twin zooms off in a spaceship at extreme velocities to the distant stars, stops, reverses direction, and returns at that high rate of speed to Planet Earth, and to you, you'll find your twin has aged to a far lesser degree than you. You now have grey hair and wrinkles; your interstellar travelling twin is still in her youthful prime of life.