The accuracy of modern Olympic timing is made possible with the use of high quality timing devices, accurate synchronisation and atomic timing. Regular quartz oscillators are fairly accurate, but they still drift, which means without regular synchronisation, their accuracy would falter UY98UZDDVGGJ . To ensure all timing devices can achieve millisecond accuracy and precise synchronisation with one another, all Olympic timing devices are synchronised with GPS atomic clocks several times a day.
A GPS time server is ideal for preventing costly leap seconds that interrupt businesses that operate on a global timescale.
UTC is an atomic clock time reference used to ensure all PCs and computer networks, no matter where they are in the world, are all running the same time. NTP time servers are used to receive a times source and distribute it around a network but there are various choices for locating a source of UTC for time reference for synchronisation.
Ethernet NTP digital wall clocks plug into an NTP times server using an Ethernet cable. This means that the time signal is sent from the NTP time server directly to the Ethernet NTP digital wall clock, maintaining its accuracy. The Ethernet digital wall clock never needs setting as it is automatically set by the time signal sent from the times server, which means it will always be accurate, and the Ethernet NTP digital wall clock requires no mains power or batteries as it gets its power form the Ethernet.
To keep precise time, computer networks have to find a source of accurate, precise and secure time, which enables all devices to be synchronised together. One of the most common used devices for achieving this are radio time synchronisation receivers.
International Telecommunications Union (ITU), based in Geneva, is voting in January to finally get rid of the leap second, effectively scrapping Greenwich Meantime.
UTC (Coordinated Universal Time) has been around since the 1970’s, and already effectively governs the world’s technologies by keeping computer networks synchronised by way of NTP time servers (Network Time Protocol), but it does have one flaw: UTC is too accurate, that is to say, UTC is governed by atomic clocks, not by the rotation of the Earth. While atomic clocks relay an accurate, unchanging form of chronology, the Earth’s rotation varies slightly from day-to-day, and in essence is slowing down by a second or two a year.
To prevent noon, when the sun is highest in the sky, from slowly getting later and later, Leap Seconds are added to UTC as a chronological fudge, ensuring that UTC matches GMT (governed by when the sun is directly above by the Greenwich Meridian Line, making it 12 noon).
The use of leap seconds is a subject of continuous debate. The ITU argue that with the development of satellite navigation systems, the internet, mobile phones and computer networks all reliant on a single, accurate form of time, a system of timekeeping needs to be precise as possible, and that leap seconds causes problems for modern technologies.
This against changing the Leap Second and in effect retaining GMT, suggest that without it, day would slowly creep into night, albeit in many thousands of years; however, the ITU suggest that large-scale changes could be made, perhaps every century or so.
If leap seconds are abandoned, it will effectively end Greenwich Meantime’s guardianship of the world’s time that has lasted over a century. Its function of signalling noon when the sun is above the meridian line started 127 years ago, when railways and telegraphs made a requirement for a standardised timescale.
If leap seconds are abolished, few of us will notice much difference, but it may make life easier for computer networks that synchronised by NTP time servers as Leap Second delivery can cause minor errors in very complicated systems. Google, for instance, recently revealed it had written a program to specifically deal with leap seconds in its data centres, effectively smearing the leap second throughout a day.
Most of us recognise how long an hour, a minute, or a second is, and we are used to seeing our clocks tick past these increments, but have you ever thought what governs clocks, watches and the time on our computers to ensure that a second is a second and an hour an hour?
Early clocks had a very visible form of clock precision, the pendulum. Galileo Galilei was the first to discover the effects of weight suspended from a pivot. On observing a swinging chandelier, Galileo realised that a pendulum oscillated continuously above its equilibrium and didn’t falter in the time between swings (although the effect weakens, with the pendulum swinging less far, and eventually stops) and that a pendulum could provide a method of keeping time.
Early mechanical clocks that had pendulums fitted proved highly accurate compared to other methods tried, with a second able to be calibrated by the length of a pendulum.
Of course, minute inaccuracies in measurement and effects of temperature and humidity meant that pendulums were not wholly precise and pendulum clocks would drift by as much as half an hour a day.
The next big step in keeping track of time was the electronic clock. These devices used a crystal, commonly quartz, which when introduced to electricity, will resonate. This resonance is highly precise which made electric clocks far more accurate than their mechanical predecessors were.
True accuracy, however, wasn’t reached until the development of the atomic clock. Rather than using a mechanical form, as with a pendulum, or an electrical resonance as with quartz, atomic clocks use the resonance of atoms themselves, a resonance that doesn’t change, alter, slow or become affected by the environment.
In fact, the International System of Units that define world measurements, now define a second as the 9,192,631,770 oscillations of a caesium atom.
Because of the accuracy and precision of atomic clocks, they provide the source of time for many technologies, including computer networks. While atomic clocks only exist in laboratories and satellites, using devices like Galleon’s NTS 6001 NTP time server.
A time server such as the NTS 6001 receives a source of atomic clock time from either GPS satellites (which use them to provide our sat navs with a way to calculate position) or from radio signals broadcast by physics laboratories such as NIST (National Institute of Standards and Time) or NPL (National Physical Laboratory).
The construction of clock, designed to tell the time for 10,000 years, is underway in Texas. The clock, when built, will stand over 60 metres tall and will have a clock face nearly three metres across.
Built by a non-profit organisation, the Long Now Foundation, the clock is being built so as to, not only still be standing in 10,000 years, but also still be telling the time.
Consisting of a 300kg gear wheel and a 140kg steel pendulum, the clock will tick every ten seconds and will feature a chime system that will allow 3.65 million unique chime variations—enough for 10,000 years of use.
Inspired by ancient engineering projects of the past, such as the Great Wall of China and the Pyramids—objects designed to last, the clock’s mechanism will feature state-of-the-art materials that don’t require lubrication of servicing.
However, being an mechanical clock, the Long Now Clock will not be very accurate and will require resetting to avoid drift otherwise the time in 10,000 years will not represent the time on Earth.
Even atomic clocks, the world’s most accurate clocks, require help in preventing drift, not because the clocks themselves drift—atomic clocks can remain accurate to a second for 100 million years, but the Earth’s rotation is slowing.
Every few years an extra second is added to a day. These Leap Seconds inserted on to UTC (Coordinated Universal Time) prevent the timescale and the movement of the Earth from drifting apart.
UTC is the global timescale that governs all modern technologies from satellite navigation systems, air traffic control and even computer networks.
While atomic clocks are expensive laboratory-based machines, receiving the time from an atomic clock is simple, requiring only a NTP time server (Network Time Protocol) that uses either GPs or radio frequencies to pick up time signals distributed by atomic clock sources. Installed on a network, and NTP time server can keep devices running to within a few milliseconds of each other and of UTC.
When we want to know the time it is very simple to look at a clock, watch or one of the myriad devices that display the time such as our mobile phones or computers. But when it comes to setting the time, we rely on the internet, speaking clock or somebody else watch; however, how do we know these clocks are right, and who is it that ensures that time is accurate at all?
Traditionally we have based time on Earth in relation to the rotation of the planet—24 hours in a day, and each hour split into minutes and seconds. But, when atomic clocks were developed in the 1950’s it soon became apparent that the Earth was not a reliable chronometer and that the length of a day varies.
In the modern world, with global communications and technologies such as GPS and the internet, accurate time is highly important so ensuring that there is a timescale that is kept truly accurate is important, but who is it that controls global time, and how accurate is it, really?
Global time is known as UTC—coordinated Universal Time. It is based on the time told by atomic clocks but makes allowances for the inaccuracy of the Earth’s spin by having occasional leap seconds added to UTC to ensure we don’t get into a position where time drifts and ends up having no relation to the daylight or night time (so midnight is always at day and noon is in the day).
UTC is governed by a constellation of scientists and atomic clocks all across the globe. This is done for political reasons so no one country has complete control over the global timescale. In the USA, the National Institute for Standards and Time (NIST), helps govern UTC and broadcast a UTC time signal from Fort Collins in Colorado.
While in the UK, the National Physical Laboratory (NPL) does the same thing and transmits their UTC signal from Cumbria, England. Other physics labs across the world have similar signals and it is these laboratories that ensure UTC is always accurate.
For modern technologies and computer networks, these UTC transmissions enable computer systems across the globe to be synchronised together. The software NTP (Network Time Protocol) is used to distribute these time signals to each machine, ensuring perfect synchronicity, while NTP time servers can receive the radio signals broadcast by the physics laboratories.
Timekeeping and accuracy is important in the running of our day-to-day lives. We need to know what time events are occurring to ensure we don’t miss them, we also need to have a source of accurate time to prevent us from being late; and computers and other technology are just as reliant on the tine as we are.
For many computers and technical systems, the time in the form of a timestamp is the only tangible thing a machine has to identify when events should occur, and in what order. Without a timestamp a computer is unable to perform any task—even saving data is impossible without the machine knowing what time it is.
Because of this reliance on time, all computer systems have in-built clocks on their circuit boards. Commonly these are quartz based oscillators, similar to the electronic clocks used in digital wrist watches.
The problem with these system clocks is that they are not very accurate. Sure, for telling the time for human purposes they are precise enough; however, machines quite often require a higher level of accuracy, especially when devices are synchronised.
For computer networks, synchronisation is crucial as different machines telling different times could lead to errors and failure of the network to perform even simple tasks. The difficult with network synchronisation is that the system clocks used by computers to keep time can drift. And when different clocks drift by differing amounts, a network can soon fall into disarray as different machines keep different times.
For this reason, these system clocks are not relied on to provide synchronisation. Instead, a far more accurate type of clock is used: the atomic clock.
Atomic clocks don’t drift (at least not by more than a second in a million years) and so are ideal to synchronise computer networks too. Most computers use the software protocol NTP (Network Time Protocol) which uses a single atomic clock time source, either from across the internet, or more securely, externally via GPS or radio signals, in which it synchronises every machine on a network to.
Because NTP ensures each device is kept accurate to this source time and ignores the unreliable system clocks, the entire network can be kept synchronised to with each machine within fractions of a second of each other.