The Complexities of Time

One of the most common questions often asked in philosophy and physics classes is ‘what is time?’ It is indeed a question that mankind has been asking throughout our history and it wasn’t until the early part of the last century and work of Einstein have we actually been able to even attempt an answer.The question itself is a misnomer. What we should really be asking is ‘when is time?’ as time itself in not a constant, neither is it an abstract concept often thought as by philosophers. The best way to regard time is as a physical dimension, similar to the other three dimensions that we see and interact with all around us.Think of a map reference. To loctate your position it requires three pieces of information or dimensions: longitude, latitude and height but that will only give us our location on Earth. To find out where we are in the Universe we need a fourth dimension – time.The Earth travels around the sun at vast speeds so any reference to location has to include time as to locate a spot on the planet you would need to know where it is at any given time.Einstein called this four dimensional Universe space-time and he identified several properties that still to this day seem so fantastic as to be science fiction rather than fact.Einstein discovered that time was not at all constant but relative to different observers and the only constant in our universe was the speed of light which was the same for all observers. Furthermore Einstein argued that differences in time would be greater for an observer traveling at very high speeds (approaching the speed of light) where time would slow down to almost a standstill making a journey across the galaxy seem like seconds, while to an observer on Earth, timing the journey (if that was at all possible) it would appear to have taken thousands of years.Fortunately here on Earth the differences in speed we travel at are less noticeable so this time dilation does not affect us. However, Einstein discovered that space time was affected by other things too, including gravity. He suggested that gravity would bend and warp space time making time run slower depending on the strength of the gravitational force. So for people on Earth time would run more slowly than for anybody choosing to live on the moon.Einstein’s theories, whilst generally accepted, could not be proved until the invention of atomic clocks in the 1950’s. It was only then when accuracies of a second every million years were obtained could Einstein’s ideas be finally observed.Not only was Einstein proved right but technologies such as GPS, communications and satellite and spacecraft navigation have to compensate for Einstein’s theories otherwise satellites would drift thousands of miles off course and our sat navs in our cars would be rendered useless.Even the Earths atomic clocks have to compensate for gravitational time dilation as those closer to sea level experience minutely more gravity and run slower to clocks at higher altitudes (albeit less than a second every million years or so).Atomic clocks are now the basis for all time keeping. A universal timescale (Coordinated Universal Time – UTC) has been developed based on the time told by atomic clocks which allows the world to communicate using NTP servers (Network Time Protocol) that ensure that all computers are running the correct time.