What Governs our Clocks

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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).

 

Precise Time on the Markets

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The stock market has been in the news a lot lately. As global uncertainty about national debts rise, the markets are in flux, with prices changing incredibly quickly. On a trading floor, every second counts and precise time is essential for global buying and selling of commodities, bonds and shares.

NTS 6001 from Galleon Systems

The international stock exchanges such as the NASDAQ and London Stock Exchange all require accurate and precise time. With traders buying and selling shares for customers across the globe, a few seconds of inaccuracy could cost millions as share prices fluctuate.

NTP servers linked to atomic clock timing signals ensure that the stock exchange keeps an accurate and precise time. As computers across the globe all receive the stock prices, as and when they change, these two use NTP server systems to maintain time.

The global timescale UTC (Coordinated Universal Time) is used as the basis for atomic clock timing, so no matter where a trader is on the globe, the same timescale prevents confusion and errors when dealing with stocks and shares.

Because of the billions of pounds worth of stocks and shares that are bought and sold on trading floors every day, security is essential. NTP servers work externally to networks, getting their time from sources such as GPS (Global Positioning System) or radio signals put out by organisations like the National Physical Laboratory (NPL) or the National Institute for Standards and Time (NIST).

The stock exchanges can’t use a source of internet because of the risk this could pose. Hackers and malicious users could tamper with the time source, leading to mayhem and cost millions and perhaps billions if the wrong time was spread around the exchanges.

The precision of internet time is limited too. Latency over distance can create delays, which could lead to errors, and if the time source ever went down, the stock markets could hit trouble.

It is not only stock markets that need precise and accurate time, computer networks across the globe concerned about security use dedicated NTP servers like Galleon Systems’ NTS 6001. Providing accurate time from both GPS and radio signals from NPL and NIST, the NTS 6001 ensure accurate, precise and secure time every day of the year.

75 Years of the Speaking Clock

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Britain’s speaking clock celebrates its 75th birthday this week, with the service still providing the time to over 30 million callers a year.

The service, available by dialling 123 on any BT landline (British Telecom), began in 1936 when the General Post Office (GPO) controlled the telephone network. Back then, most people used mechanical clocks, which were prone to drift. Today, despite the prevalence of digital clocks, mobile phones, computers and a myriad number of other devices, the BT speaking clock still provides the time to 30 million callers a year, and other networks implement their own speaking clock systems.

Much of the speaking clock’s continuing success is perhaps down to the accuracy that it keeps. The modern speaking clock is accurate to five milliseconds (5/1000ths of a second), and kept precise by the atomic clock signals provided by NPL (National Physical Laboratory) and the GPS network.

But the announcer declaring the time ‘after the third stroke’ provides people with a human voice, something other time-telling methods don’t provide, and may have something to do with why so many people still use it.

Four people have had the honour of providing the voice for the speaking clock; the current voice of the BT clock is Sara Mendes da Costa, who has provided the voice since 2007.

Of course, many modern technologies require an accurate source of time. Computer networks that need to keep synchronised, for security reasons and to prevent of errors, require a source of atomic clock time.

Network time servers, commonly called NTP servers after Network Time Protocol that distributes the time across the computers on a network, use either GPS signals, which contain atomic clock time signals, or by radio signals broadcast by places like NPL and NIST (National Institute for Standards and Time) in the US.

How Long is a Day?

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A day is something most of us take for granted, but the length of a day is not as simple as we may think.

A day, as most of us know, is the time it takes for the Earth to spin on its axis. Earth takes 24 hours to do one complete revolution, but other planets in our solar system have day lengths far different to ours.

Galleon NTS 6001

The largest planet, Jupiter, for instance, takes less than ten hours to spin a revolution making a Jovian day less than half of that of Earth, while a day on Venus is longer than its year with a Venusian day 224 Earth days.

And if you think of those plucky astronauts on the international Space Station, hurtling around the Earth at over 17,000 mph, a day for them is just 90 minutes long.

Of course, few of us will ever experience a day in space or on another planet, but the 24-hour day we take for granted is not as steadfast as you may think.

Several influences govern the revolution of the Earth, such as the movement of tidal forces and the effect of the Moon’s gravity. Millions of years ago, the Moon was much closer to Earth as it is now, which caused much higher tides, as a consequence the length of Earth’s day was shorter—just 22.5 hours during the time of the dinosaurs. And ever since the earth has been slowing.

When atomic clocks were first developed in the 1950’s, it was noticed that the length of a day varied. With the introduction of atomic time, and then Coordinated Universal Time (UTC), it became apparent that the length of a day was gradually lengthening. While this change is very minute, chorologists decided that to ensure equilibrium of UTC and the actual time on Earth—noon signifying when the sun is at its highest above the meridian—additional seconds needed to be added, once or twice a year.

So far, 24 of these ‘Leap Seconds’ have been since 1972 when UTC first became the international timescale.

Most technologies dependent on UTC use NTP servers like Galleon’s NTS 6001, which receives accurate atomic clock time from GPS satellites. With an NTP time server, automatic leap second calculations are done by the hardware ensuring all devices are kept accurate and precise to UTC.

 

The Truth about Time

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As a manufacturer of NTP time servers, synchronizing computer networks and keeping them accurate to within a few milliseconds of international UTC time (Coordinated Universal Time), we often think we can keep pretty good track of time.

Time, however, is quit elusive and is not the fixed entity we often assume it is, indeed time, and the time told on Earth is not constant and is affected by all sorts of things.

Since Einstein’s famous equation, E=MC2 it has been acknowledged that time is not constant, and that the only constant in the universe is the maximum velocity of light. Time, as Einstein discovered, is affected by gravity, making the time on Earth run slightly slower than time in deep space, likewise, on planetary bodies with a larger mass than Earth, time runs even slower.

Time slows down when you approach very fast speeds too. The property of time, known as time dilation, was discovered by Einstein and means that at close to the speed of light, time almost stands still (and makes interstellar travel a possibility for science fiction writers).

Generally, living on Earth, these differences in time are not felt, and indeed the slowing of time caused by Earth’s gravity is so minute, highly precise atomic clocks are required to measure it.

However, the time we use to govern our lives is also affected by other factors. Since humans first evolved, we have been used to a day lasting just over 24 hours.  However, the length of a day on Earth is not fixed, and has been changing for the last few billion years.

Each day on Earth differs from the previous to the next one. Often these differences are minute, but year on year, the changes add up as the affect of the moon’s gravity and tidal forces act as a brake on the Earth’s spin.

To cope with this, the global timescale UTC (Coordinated Universal Time) has to be adjusted to prevent the day from drifting out of sync (and we end up with noon at night and midnight during the day—although at the current slowing of the Earth, this would take many thousands of years).

The adjustment in our time is known as leap seconds which are added either once or twice a year to UTC. Anybody using a NTP time server (Network Time Protocol) to synchronise their computer network too, needn’t worry, however, as NTP servers will automatically account for these changes.

Keeping the World Ticking Over The Global Timekeepers

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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.

How GPS Keeps Clocks Accurate

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While many of us are aware of GPS (Global Positioning System) as a navigational tool and many of us have ‘sat navs’ in our cars, but the GPS network has another use that is also important to our day-to-day lives but few people realise it.

GPS satellites contain atomic clocks which transmit to earth an accurate time signal; it is this broadcast that satellite navigation devices use to calculate global position. However, there are other uses for this time signal besides navigation.

Nearly all computer networks are kept accurate to an atomic clock. This is because miniscule accuracies across a network can lead to until problems, from security issues to data loss. Most networks use a form of NTP (Network Time Protocol) to synchronise their networks, but NTP requires a main time source to sync to.

GPS is ideal for this, not only is it an atomic clocks source, which NTP can calculate UTC (Coordinated Universal Time) from, which means that the network will be synchronised to every other UTC network on the globe.

GPS is an ideal source of time as it is available literally everywhere on the planet as long as the GPS antenna has a clear view of the sky. And it is not only computer networks that require atomic clock time, all sorts of technologies require accurate synchronisation: traffic lights, CCTV cameras, air traffic control, internet servers, indeed many modern applications and technology without us realising is being kept true by GPS time.

Top use GPS as a source of time, a GPS NTP server is required. These connect to routers, switches or other technology and receive a regular time signal from the GPS satellites. The NTP server then distributes this time across the network, with the protocol NTP continually checking each device to ensure it is not drifting.

GPS NTP servers are not only accurate they are also highly secure. Some network administrators use internet time servers as a source of time but this can lead to problems. Not only is the accuracy of many of these sources questionable, but the signals can be hijacked by malicious software which can breach the network firewall and cause mayhem.

How the Moon Affects Time on Earth

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We take it for granted that a day is twenty-four hours. Indeed, our body’s circadian rhythm is finally tuned to cope with a 24-hour-day. However, a day on Earth was not always 24 hours long.

In the early days of the Earth, a day was incredibly short – just five hours long, but by the time of the Jurassic period,  when dinosaurs roamed the Earth, a day had lengthened to about 22.5 hours.

Of course now, a day is 24-hours and has been since humans evolved, but what has caused this gradual lengthening. The answer lies with the Moon.

The moon used to be a lot closer to the Earth and the effect of its gravity was therefore, a lot stronger. As the moon drives tidal systems, these were a lot stronger in the early days of the Earth, and the consequence was that the Earth’s spin slowed, the tugging of the moon’s gravity and tidal forces on the Earth, acing like a brake on the rotation of the planet.

Now the moon is farther away, and is continuing to move away even farther, however the effect of the moon is still felt on Earth, with a consequence that Earth’s day is still slowing down, albeit minutely.

With modern atomic clocks, it is now possible to account for this slowing and the global timescale used by most technologies to ensure time synchronisation, UTC (Coordinated Universal Time), has to account for this gradual slowing, otherwise, because of the extreme accuracy of atomic clocks, eventually day would slip into night as the Earth slowed and we didn’t adjust our clocks.

Because of this, once or twice a year, an extra second is added to the global timescale. These leap-seconds, as they are known, have been added since the 1970’s when UTC was first developed.

For many modern technologies where millisecond accuracy is required, this can cause problems. Fortunately, with NTP time servers (Network Time Protocol) these leap seconds are accounted for automatically, so any technologies hooked up to an NTP server need not worry about this discrepancy.

NTP servers are used by time sensitive technology and computer networks worldwide to ensure precise and accurate time, all the time, regardless of what the heavenly bodies are doing.

Press Release: Galleon Systems Launch New Website

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Atomic clock and NTP server specialists, Galleon Systems, have relaunched their website providing an improved platform to showcase their wide range of time synchronisation and network time server products.

Galleon Systems, who have been providing atomic clock and time server products to industry and commerce for over a decade, have redesigned their website to ensure the company continues to be world leaders in providing accurate, secure and reliable time synchronisation products.

With detailed descriptions of their product range, new product pictures and a revamped menu system to provided better functionality and user experience, the new website includes all of Galleons extensive range of NTP server systems (Network Time Protocol) and atomic clock synchronisation products.

Time servers from Galleon Systems are accurate to within a fraction of a second and are a secure and reliable method of getting a source of atomic clock time for computer networks and technological applications.

Using either GPS or the UKs MSF radio signal (DSF in Europe WWVB in the USA), time servers from Galleon Systems can keep hundreds of devices on a network accurate to within a few milliseconds of the international timescale UTC (Coordinated Universal Time).

Galleon Systems product range includes a variety of NTP time servers that can receive either GPS or radio referenced signals, dual systems that can receive both, simple radio controlled atomic clock servers, and a range of large network digital and analogue wall clocks.

Manufactured in the UK, Galleon Systems have a wide range of NTP and time synchronisation devices used worldwide by thousands of organizations who need accurate, reliable and precise time. For more information please visit their new website: www.galsys.co.uk

Mechanisms of Time History of Chronological Devices

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Nearly every device seems to have a clock attached to it these days. Computers, mobile phones and all the other gadgets we use are all good sources of time. Ensuring that no matter where you are a clock is never that far away – but it wasn’t always this way.

Clock making, in Europe, started around the fourteenth century when the first simple mechanical clocks were developed. These early devices were not very accurate, losing perhaps up to half an hour a day, but with the development of pendulums these devices became increasingly more accurate.

However, the first mechanic al clocks were not the first mechanical devices that could tell and predict time. Indeed, it seems Europeans were over fifteen hundred years late with their development of gears, cogs and mechanical clocks, as the ancients had long ago got there first.

Early in the twentieth century a brass machine was discovered in a shipwreck (Antikythera wreck) off Greece, which was a device as complex as any clock made in Europe up in the mediaeval period. While the Antikythera mechanism is not strictly a clock – it was designed to predict the orbit of planets and seasons, solar eclipses and even the ancient Olympic Games – but is just as precise and complicated as Swiss clocks manufactured in Europe in the nineteenth century.

While Europeans had to relearn the manufacture of such precise machines, clock making has moved on dramatically since then. In the last hundred or so years we have seen the emergence of electronic clocks, using crystals such as quartz to keep time, to the emergence of atomic clocks that use the resonance of atoms.

Atomic clocks are so accurate they won’t drift by even a second in a hundred thousand years which is phenomenal when you consider that even quartz digital clocks will drift several seconds n a day.

While few people will have ever seen an atomic clock as they are bulky and complicated devices that require teams of people to keep them operational, they still govern our lives.

Much of the technologies we are familiar with such as the internet and mobile phone networks, are all governed by atomic clocks. NTP time servers (Network Time Protocol) are used to receive atomic clock signals often broadcast by large physics laboratories or from the GPS (Global Positioning System) satellite signals.

NTP servers then distribute the time around a computer network adjusting the system clocks on individual machines to ensure they are accurate. Typically, a network of hundreds and even thousands of machines can be kept synchronised together to an atomic clock time source using a single NTP time server, and keep them accurate to within a few milliseconds of each other (few thousandths of a second).