Wednesday, 1 January 2014

Calendars, Clocks and the joys of Time keeping

A sundial (Photo taken by Alexandre Mirgorodski)
I'd like to wish all the readers of this blog a very happy and prosperous New Year and would like to indulge a little of your time to talk about the very thing that allow us to have these celebrations in the first place; the science of chronometry; the science of timekeeping. This is not to be confused with horology which is the study of the instruments used to measure time.

Time keeping is a very fastidious sort of activity you can ever engage in. This is because time is but a continuous value; you can keep on dividing it till you end up with extremely small measurements like microsecond (millionth of a second), nanosecond (billionth) or even picoseconds (trillionth), depending on the level of accuracy you want.

What's worse, we have come to realise that the time is not an absolute dimension, but a relative one, i.e. it changes in the rate of progression due to the distortion of the space-time continuum (imagine reality as a fabric with time being one of the threads; gravitational distortion changes the appearance of reality as well as the time in said reality). These distortions are not very noticeable when we measure time with your dependable Rolex watch for two reasons: first, it's not accurate enough. You need to have a pretty high level of measurement to detect the subtle changes in the flow of time due to the gravitational distortion brought about by Earth. Global Positioning Satellites have such exquisitely accurate clocks that they have to take this discrepancy into account when calculating positions on the ground where time moves slightly slower.

Also, just to muddy the waters a bit, the standards used to measure time and to set our various clocks to may tend to gain or lose time as they keep on ticking. These errors can accumulate with time and cause us to become hopelessly disconnected from reality.
A chip-sized atomic clock; these
are some of the most powerful
time keepers around. (Commons)

Speaking of reality, we do like it if these tick-tocking standards march to the tune of our everyday lives; we wish to wake up when the sun's actually up and not before or we would like the clock to be accurate enough to tell our computers to start trading with the stock markets the moment the opening bell rings. And astronomers would like the little star in the sky to be right there when they expect it to. It is incredible to realise how much humans have been dependent on clocks to measure and predict so many regular aspects of our lives. With time, our clocks have become more elaborate (think computers) but we are still vexed by the need to accurately match this regularity to human nuances (think time zones, calender types and the bizarre day light savings). Our desire to mark out cyclical events in our lives (the calender or almanac) sometimes forces us to make reconcile natural temporal variations with our more accurate ability of timekeeping. This brings out very interesting problems.

Consider for example a software developer trying to write up an app that needs to do some accurate international time keeping. The result is illustrated very well in this video. Happy 2014 everybody!

P.S. That little reference about Google's way of dealing with some of the issues mentioned can be found here.