Category: timekeepers

Milestones in Chronology From Crystals to Atoms

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Telling the time may seem a simple affair these days with the number of devices that display the time to us and with the incredible accuracy of devices such as atomic clocks and network time servers it is quite easy to see how chronology has been taken for granted.

The nanosecond accuracy that powers technologies such as the GPS system, air traffic control and NTP server systems (Network Time Protocol) is a long way from the first time pieces that were invented and were powered by the movement of the sun across the heavens.

Sun dials were indeed the first real clocks but they obviously did have their downsides – such as not working at night or in cloudy weather, however, being able to tell the time fairly accurately was a complete innovation to civilisation and helped for more structured societies.

However, relying on celestial bodies to keep track of time as we have done for thousands of years, would not prove to be a reliable basis for measuring time as was discovered by the invention of the atomic clock.

Before atomic clocks, electronic clocks provided the highest level of accuracy. These were invented at the turn of the last century and while they were many times more reliable than mechanical clocks they still drifted and would lose a second or two every week.

Electronic clocks worked by using the oscillations (vibrations under energy) of crystals such as quartz, however, atomic clocks use the resonance of individual atoms such as caesium which is such a high number of vibrations per second it makes the incredibly accurate (modern atomic clocks do not drift by even a second every 100 million years).

Once this type of time telling accuracy was discovered it became apparent that our tradition of using the rotation of the earth as a means of telling time was not as accurate as these atomic clocks. Thanks to their accuracy it was soon discovered the Earth’s rotation was not precise and would slow and speed up (by minute amounts) each day. To compensate for this the world’s global timescale UTC (Coordinated Universal Time) has additional seconds added to it once or twice a year (Leap seconds).

Atomic clocks provide the basis of UTC which is used by thousands of NTP servers to synchronise computer networks to.

Heroes of Time

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Chronology – the study of time- has provided science and technology with some incredible innovations and possibilities. From atomic clocks, NTP servers and the GPS system, true and accurate chronology has changed the shape of the world.

Time and the way it is counted has been a preoccupation of mankind since the earliest civilisations. Early chronologists spent their time trying to establish calendars but this proves to be more complicated than first imagined primarily because the earth takes a quarter of a day more than 365 days to orbit the sun.

Establishing the right number of leap days was one of the first challenges and it took several attempts at calendars until the modern Gregorian calendar became adopted by the globe.

When it came to monitoring time at a smaller level great advances were made by Galileo Galilei who would have built the first pendulum clock if only his death hadn’t interrupted his plans. Pendulums were finally invented by Christiaan Huygens and provided the first true glimpse of accurately monitoring the time throughout the day.

The next steps in chronology couldn’t take place though until we had a better understanding of time itself. Newton (Sir Isaac) had the first ideas and had the notion time was absolute” and would flow “equably” for all observers. This would have been an obvious idea to Newton as many of us regard time as unchanging but it was Einstein in his special theory of relativity that proposed that in fact time wasn’t a constant and would differ to all observers.

It was Einstein’s ideas that proved correct and his model of time and space paved the way for many of the modern technologies we take for granted today such as the atomic clock.

However, chronology doesn’t stop there, timekeepers are constantly looking for ways of increasing accuracy with modern atomic clocks so precise they would not lose a second in millions of years.

There are other notable figures in the modern world of chronology too. Professor David Mills from the University of Delaware devised a protocol in the 1980’s to synchronise computer networks.

His Network Time Protocol (NTP) is now used in computer systems and networks all over the world via NTP time servers. A NTP server ensures computers on opposite sides of the globe can run exactly the same time.