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.

Clock to Run for 10,000 Years

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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.

 

 

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.

 

Clocks that Changed Time

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If you’ve ever tried to keep track of time without a watch or clock, you’ll realise just how difficult it can be. Over a few hours, you may get to within half an hour of the right time, but precise time is very difficult to measure without some form of chronological device.

Before the use of clocks, keeping time was incredibly difficult, and even losing track of days of the years became easy to do unless you kept as daily tally. But the development of accurate timepieces took a long time, but several key steps in chronology evolved enabling closer and closer time measurements.

Today, with the benefit of atomic clocks, NTP servers and GPS clock systems, time can be monitored to within a billionth of a second (nanosecond), but this sort of accuracy has taken mankind thousands of years to accomplish.

 

Stonehenge–ancient timekeeping

Stonehenge

With no appointments to keep or a need to arrive at work on time, prehistoric man had little need for knowing the time of day. But when agriculture started, knowing when to plant crops became essential for survival. The first chronological devices such as Stonehenge are believed to have been built for such a purpose.

Identifying the longest and shortest days of the year (solstices) enabled early farmers to calculate when to plant their crops, and probably provided a lot of spiritual significance to such events.

Sundials

The provided the first attempts at keeping track of time throughout the day. Early man realised the sun moved across the sky at regular paths so they used it as a method of chronology. Sundials came in all sorts of guises, from obelisks that cast huge shadows to small ornamental sundials.

Mechanical Clock

The first true attempt at using mechanical clocks appeared in the thirteenth century. These used escapement mechanisms and weights to keep time, but the accuracy of these early clocks meant they’d lose over an hour a day.

Pendulum Clock

Clocks first became reliable and accurate when pendulums began appearing in the seventeenth century. While they would still drift, the swinging weight of pendulums meant that these clocks could keep track of first minutes, and then the seconds as engineering developed.

Electronic Clocks

Electronic clocks using quartz or other minerals enabled accuracy to parts of a second and enabled scaling down of accurate clocks to wristwatch size. While mechanical watches existed, they would drift too much and required constant winding. With electronic clocks, for the first time, true hassle free accuracy was achieved.

Atomic Clocks

Keeping time to thousands, millions and even billion parts of a second came when the first atomic clocks arrived in the 1950’s. Atomic clocks were even more accurate than the rotation of the Earth so Leap Seconds needed developing to make sure the global time based on atomic clocks, Coordinated Universal Time (UTC) matched the path of the sun across the sky.

 

Summer Solstice The Longest Day

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June 21 marks the summer solstice for 2011. The summer solstice is when the Earth’s axis is most inclined to the sun, providing the most amount of sunshine for any day of the year. Often known as Midsummer’s day, marking the exact middle of the summer, periods of daylight get shorter following the solstice.

For the ancients, the summer solstice was an important event. Knowing when the shortest and longest days of the year were important to enable early agricultural civilisations to establish when to plant and harvest crops.

Indeed, the ancient monument of Stonehenge, in Salisbury, Great Britain, is thought to have been erected to calculate such events, and is still a major tourist attraction during the solstice when people travel from all over the country to celebrate the event at the ancient site.

Stonehenge is, therefore, one of the oldest forms of timekeeping on Earth, dating back to 3100BC. While nobody knows exactly how the monument was built, the giant stones were thought to have been transported from miles away—a mammoth task considering the wheel hadn’t even been invented back then.

The building of Stonehenge shows that timekeeping was as important to the ancients as it is to us today. The need for acknowledging when the solstice occurred is perhaps the earliest example of synchronisation.

Stonehenge probably used the setting and rising of the sun to tell the time. Sundials also used the sun to tell the time way before the invention of clocks, but we have come a long way from using such primitive methods in our timekeeping now.

Mechanical clocks came first, and then electronic clocks which were many times more accurate; however, when atomic clocks were developed in the 1950’s, timekeeping became so accurate that even the Earth’s rotation couldn’t keep up and an entirely new timescale, UTC (Coordinated Universal Time) was developed that accounted for discrepancies in the Earth’s spin by having leap seconds added.

Today, if you wish to synchronise to an atomic clock, you need to hook up to a NTP server which will receive an UTC time source from GPS or a radio signal and allow you to synchronise computer networks to maintain 100% accuracy and reliability.

Stonehenge–Ancient timekeeping

Cyber Attacks and the Importance Time Server Security

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The media is full of stories of cyber terrorism, state sponsored cyber warfare and internet sabotage. While these stories may seem like they come from a science fiction plot, but the reality is that with so much of the world now dependent on computers and the internet, cyber attacks are a real concern for governments and businesses alike.

Crippling a website, a government server or tampering with systems like air-traffic control can have catastrophic effects—so no wonder people are worried. Cyber attacks come in so many forms too. From computer viruses and trojans, that can infect a computer, disabling it or transferring data to malicious users; distributed denial of service attacks (DDoS) where networks become clogged up preventing normal use; to border gateway protocol (BGP) injections, which hijack server routines causing havoc.

As precise time is so important for many technologies, with synchronisation crucial in global communication, one vulnerability that can be exploited is the online time server.

By sabotaging a NTP server (Network Time Protocol) with BGP injections, servers that rely on them can be told it’s a completely different time than it is; this can cause chaos and result in a myriad of problems as computers rely solely on time to establish if an action has or hasn’t taken place.

Securing a time source, therefore, is essential for internet security and for this reason, dedicated NTP time servers that operate externally to the internet are crucial.

Receiving time from the GPS network, or radio transmissions from NIST (National Institute for Standards and Time) or the European physical laboratories, these NTP servers can’t be tampered with by external forces, and ensure that the network’s time will always accurate.

All essential networks, from stock exchanges to air traffic controllers, utilise external NTP servers for these security reasons; however, despite the risks, many businesses still receive their time code from the internet, leaving them exposed to malicious users and cyber attacks.

Dedicated GPS Time Server--immune to cyber attacks

Atomic Clocks now Accurate to a Quintillionth of a Second?

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Development in clock accuracy seems to increase exponentially. From the early mechanical clocks, there were only accurate to about half an hour a day, to electronic clocks developed at the turn of the century that only drifted by a second. By the 1950’s, atomic clocks were developed that became accurate to thousandths of a second and year on year they have becoming ever more precise.

Currently, the most accurate atomic clock in existence, developed by NIST (National Institute for Standards and Time) loses a second every 3.7 billion years; however, using new calculations researchers suggest they can now come up with a calculation that could lead to an atomic clock that would be so accurate it would lose a second only every 37 billion years (three times longer than the universe has been in existence).

This would make the atomic clock accurate to a quintillionth of a second (1,000,000,000,000,000,000th of a second or 1x 1018). The new calculations that could aid the development of this sort of precision has been developed by studying the effects of temperature on the miniscule atoms and electrons that are used to keep the atomic clocks ‘ticking’. By working out the effects of variables like temperature, the researchers claim to be able to improve the accuracy of atomic clock systems; however, what possible uses does this accuracy have?

Atomic clock accuracy is becoming ever relevant in our high technology world. Not only do technologies like GPS and broadband data streams rely on precise atomic clock timing but studying physics and quantum mechanics requires high levels of accuracy enabling scientists to understand the origins of the universe.

To utilise an atomic clock time source, for precise technologies or computer network synchronisation, the simplest solution is to use a network time server; these devices receive a time stamp direct from an atomic clock source, such as GPS or radio signals broadcast by the likes of NIST or NPL (National Physical Laboratory).

These time servers use NTP (Network Time Protocol) to distribute the time around a network and ensure there is no drift, making it possible for your computer network to be kept accurate to within milliseconds of an atomic clock source.

Network Time Server

Keeping Track of Global Time

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So much business these days is conducted across borders, countries and continents. Global trade and communication is an important aspect for all sorts of industries, trades and businesses.

Of course, communicating across borders often means communicating across time zones too, and this poses problems for both people and computers. When those in United States start work, Europeans are half way through their day, while those in the Far East have gone to bed.

Knowing the time in several countries is, therefore, important for many people, but fortunately, many solutions exist to help.

Modern operating systems like Windows 7 have facilities that allow you to show several time zones on the computer clock, while web pages and apps such as:  https://www.worldtimebuddy.com offer an easy way to work out the different time across time zones.

Many offices use multiple analogue and digital wall clocks to provide staff with easy access to the time in important trade countries, sometimes these use atomic clock receivers to maintain perfect accuracy, but what about computers? How do they deal with different time zones?

The answer lies in the global timescale UTC (Coordinated Universal Time). UTC was developed following the invention of atomic clocks. Kept precise by a constellation of these super-accurate clocks, UTC is the same across the globe enabling computers to communicate effectively without the differences in time zones affecting functionality.

To ensure preciseness in communication, computer networks need an accurate source of UTC as system clocks are nothing more than quartz oscillators, which can drift by several seconds a day—a long time for computer communication.

A software protocol, NTP (Network Time Protocol) ensures that this time source is distributed around the network, maintaining its accuracy.

NTP servers receive the source of UTC, often from sources such as GPS or radio referenced signals broadcast by NPL in the UK (National Physical Laboratory—transits the MSF signal from Cumbria) or NIST in the USA (National Institute of Standards and Time—transmits the WWVB signal from Colorado).

With UTC and NTP time servers, computer networks across the globe can communicate precisely and error-free enabling trouble free computing and truly global communication.

NTP server

Samoa Leaps 24 Hours into the Future

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The Pacific Island of Samoa, once the last place on Earth to see the sunset, is to move the entire nation into the future by 24 hours!

Of course, the Samoans haven’t discovered the secrets to time travel, but are skipping an entire day to make their nation fall on the other side of the International Date Line (IDL).

The International Date Line (IDL) the imaginary longitudinal line on the surface of the Earth where the date changes as a ship or aeroplane travels east or west across it. Since 1892, Samoa has sat on the eastern side of the IDL, but now the country’s Prime Minsister, Tuilaepa Sailele Malielegaoi intends shifting the nation to the western side, in essence skipping a day, making trade with neighbouring Australia and New Zealand easier.

When the change goes ahead at the end of the year, Samoa’s population of 180,000 will lose a day, going from 29 December straight to 31 December (The 30 December was chosen so presumably Samoan’s can still celebrate New Year’s Eve).

Samoa isn’t the only country to jump forward in time. When changing from the Julian calendar to the Gregorian in 1752, the British Empire had to skip 11 days, while Russia, the last European country to adopt the Gregorian calendar, had to skip 13 days (interestingly this makes the anniversary of the October Revolution fall on 7 November).

Difficulties with Time Zones

While Samoa’s difficult with trade has necessitated this change, a global economy means that a universal time system is necessary for communication between countries in different time zones.

UTC-Coordinated Universal Time was set-up for just this purpose. Governed by atomic clocks, the world’s most accurate timepieces, UTC allows the entire world to be synchronised to the exact same time.

UTC is often used by technologies such as computer networks to allow communication across the globe, preventing errors and miscommunication. Most technologies utilise NTP servers (Network Time Protocol) to receive a source of UTC time—either from the internet, GPS signals or radio frequencies—and distributes it around the computer network to ensure every device is synchronised to the same time.

Samoa is to move the other side of the International Date Line

Keeping the World Synchronised A Brief History

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Global time synchronisation may seem like a modern need, we do after all live in a global economy. With the internet, global financial markets and computer networks separated by oceans and continents—keeping everybody running in synchronisation is a crucial aspect of the  modern world.

Yet, a need for global synchronicity began a lot earlier than the computer age. International standardisation of weights and measures began after the French revolution when the decimal system was introduced and a platinum rod and weight representing the metre and the kilogram were installed in the Archives de la République in Paris.

Paris eventually became the central head of the International System of Units, which was fine for weights and measures, as representatives from different countries could visit the vaults to calibrate their own base measurements; however, when it came to standardising time, with the increased use of transatlantic travel following the steamer, and then the aeroplane, things became tricky.

Back then, the only clocks were mechanical and pendulum driven. Not only would the base clock that was situated in Paris drift on a daily basis, but any traveller from the other side of the world wanting to synchronise to it, would have to visit Paris, check the time on the vault’s clock, and then carry their own clock back across the Atlantic—inevitable arriving with a clock that had drifted perhaps several minutes by the time the clock arrived back.

With the invention of the electronic clock, the aeroplane and transatlantic telephones, things became easier; however, even electronic clocks can drift several seconds in a day so the situation wasn’t perfect.

These days, thanks to the invention of the atomic clock, the SI standard of time (UTC: Coordinated Universal Time) has so little drift even a 100,000 years wouldn’t see the clock lose a second. And synchronising to UTC couldn’t be simpler no matter where you are in the world—thanks to NTP (Network Time Protocol) and NTP servers.

Now using GPS signals or transmissions put out by organisations like NIST (National Institute for Standards and Time-WVBB broadcast) and NPL (National Physical Laboratory—MSF broadcast) and using NTP servers, ensuring you are synchronised to UTC is simple.

NTP servers like Galleon’s NTS 6001 GPS receive a atomic clock time signal and distributes it around a network keeping every device to within a few milliseconds of UTC.

 

Galleon's NTS 6001 GPS Time Server