The Riddle of Time
Time seems to flow constantly
Time is a brisk wind, for each hour it brings something new... but who can understand and measure its sharp breath, its mystery and its design? -Paracelsus
Time waits for no man, heals all wounds and is often taken sweetly. The seeming constancy of flow of time, moment to moment, becomes the narrative that is our conscious life.
Flow is witnessed by clocks that pulse with measured regularity. As such, we have become content with the notion that time moves at a constant rate. This however is an illusion that extends out of our reliance on that which only appears constant.
The apparent constancy of clocks is determined by measuring the frequency of reliably reproducable phenomenon. The first clocks measured the day by the procession of the sun through the sky and then the year by the transit of the sun from the tropics of Cancer to Capricorn. Time was a measure of the distance the earth travelled, both around its axis and its orbit around the sun.
Next, applying pressure to quartz crystals produces an electrical signal whose frequency was used for deliniating seconds from minutes, minutes from hours. In modernity, the International System of Units (SI) has defined the second as the duration of 9192631770 cycles of radiation corresponding to the transition between two energy levels of the caesium-133 atom.
We measure time by counting consistently occuring events. From this vantage point, time appears to be flowing with constancy because our perseption of it is always measured by an external source.
Time as the standard of measure
All other scientific calculations rely on time as the standard of interval by which measurments are made. Even the most modern definitions of distance require a measurement of time to determine interval, where the definition of a metre is given by "The length of the path travelled by light in vacuum during a time interval of 1⁄299,792,458 of a second".
Time is the foundation of experimental measurement; its constancy is assumed and its intervals are used to create units of all other forms of measure. Time is the independent variable, relying on no other measure to mete out its discourse.
Time is Relative to the observer
Breaking out of our reliance on thrid-party counting of events as timekeeping required Einstein to raise the notion of the relativity of time measurement . Under relativity, it is postulated that the experience of time slows when the observer travels close to the speed of light. An accurate clock at rest with respect to one observer may be measured to tick at a different rate when compared to a second observer's own equally accurate clocks. This effect arises neither from technical aspects of the clocks nor from the fact that signals need time to propagate, but from the nature of space-time itself.
This all leads to the understanding that time is perceived differently than it is measured and that using an external measurement of time merely creates the illusion of the constancy of time.
Furthermore, the perception of time, for the obseerver, is based around the rate of change of time. In short, different observers under different conditions will experience variation in the rate of change of time; the state and situation of the observer will greatly affect the perceived duration of a unit of time. In short, the experience a second of time will change based on the conditions under which the second is observed.
Under different conditions, the perception of the rate of change of time will vary. The experience of a unit of time will be different for different observers.
