Clocks - From the Sundial to the NTP server

Time is a concept that occupies the thoughts of humans since the earliest civilizations. One can only have been during the last century that we began to understand the time, thanks to the work of Albert Einstein, but the extent of his visit was an important element of society.

Historically, the time has been measured with the rotation of the Earth and other astronomical cycles such as the phases of the moon. The measurement of time and thus the identification of key events during the day, month or year has been crucial to the development of agriculture, religion, and complex societies.

While the calendars have been used for millennia, prehistoric monuments like Stonehenge, thought to indicate the winter solstice and summer and then locate the longest and shortest days of planting cultures, with small increments of time measurement is been a technological challenge.

The first watches were nothing but the timers, using water, burning candles and sand. They were able to measure a defined period, but less useful for identifying how much time left until expiration or other important events.

The sundial was the first real that you can watch (on a sunny day), to divide the day into equal portions, and thus provide a consistent measure of the day.

The mechanical clock appeared in the fourteenth century. While their technology is based on simple mechanics and were less accurate than sundials exist, they provide a solution to the obvious disadvantages of (day dial opaque).

Mechanical clocks really came into their own once the pendulum was developed in 1600 that provided the existing mechanical clocks can provide better accuracy. The development of mechanical clocks, pendulum engine went up over the centuries to come, and have become increasingly accurate.

However, once it was discovered that some crystals will oscillate at an exact price under the influence of an electric current, electronic watches resume as soon as he realized that the people provided much better precision.

However, during 1950, the atomic clock was developed, they used the oscillation of a single atom (usually cesium) which vibrates at a precise speed per second. Thank you to the atomic clocks that we have just discovered that the traditional way of using the rotation of the Earth and other celestial bodies as the basis of time-keeping would soon cause problems like Earth, was discovered, it would slow or speed up its rotation due to the effects of gravity on the moon.

If nothing is done, then the time told by atomic clocks (International Atomic Time, TAI) would be out of sync with the Earth and slowly becomes a date night.

A solution was found in UTC (Coordinated Universal Time), when leap seconds were added to compensate for the slowing of Earth's rotation.

UTC and atomic clocks have made it possible technologies such as satellites, global communication and the Internet. Most computer networks are governed by an atomic clock using NTP (Network Time Protocol). NTP servers receive the time signal from an atomic clock is a radio signal from the United States or GPS (Global Positioning System) network. This allows computers around the world to be synchronized at the same time scale (UTC), allowing time-sensitive operations, such as stock market and Internet commerce.