Category: atomic clocks

What Governs our Clocks

  |   By

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).

 

Hackers and Time Servers

  |   By

Computer hacking is a common subject in the news. Some of the biggest companies have fallen victim to hackers, and for a myriad of reasons. Protecting computer networks from invasion from malicious users is an expensive and sophisticated industry as hackers use many methods to invade a system.

Various forms of security exist to defend against unauthorised access to computer networks such as antivirus software and firewalls.

One area often overlooked, however, is where a computer network gets it source of time from, which can often be a vulnerable aspect to a network and a way in for hackers.

Most computer networks use NTP (Network Time Protocol) as a method of keeping synchronised. NTP is excellent at keeping computers at the same time, often to within a few milliseconds, but is dependent on a single source of time.

Because computer networks from different organisations need to communicate together, having the same source of time makes sense, which is the reason most computer networks synchronise to a source of UTC (Coordinated Universal Time).

UTC, the world’s global timescale, is kept true by atomic clocks and various methods of utilising UTC are available.

Quite often, computer networks use an internet time source to obtain UTC but this is often when they run into security issues.

Using internet time sources leave a computer network open to several vulnerabilities. Firstly, to allow access to the internet time source, a port needs keeping open in the system firewall (UDP 123). As with any open port, unauthorised users could take advantage of this, using the open port as a way into the network.

Secondly, if the internet time source itself if tampered with, such as by BGP injection (Border Gateway Protocol) this could lead to all sorts of problems. By telling internet time servers it was a different time or date, major havoc could ensue with data getting lost, system crashes—a type of Y2K effect!

Finally, internet time servers can’t be authenticated by NTP and can also be inaccurate. Vulnerable to latency and affected to distance, errors can also occur; earlier this year some reputable time servers lost several minutes, leading to thousands of computer networks receiving the wrong time.

To ensure complete protection, dedicated and external time servers, such as Galleon’s NTS 6001 are the only secure method of receiving UTC. Using GPS (or a radio transmission) an external NTP time server can’t be manipulated by malicious users, is accurate to a few milliseconds, can’t drift and is not susceptible to timing errors.

 

75 Years of the Speaking Clock

  |   By

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

  |   By

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.

 

 

Clocks that Changed Time

  |   By

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.

 

Leap Second Argument Rumbles On

  |   By

The argument about the use of the Leap Second continues to rumble on with astronomers again calling for the abolition of this chronological ‘fudge.’

Galleon's NTS 6001 GPS

The Leap Second is added to Coordinated Universal Time to ensure the global time, coincides with the movement of the Earth. The problems occur because modern atomic clocks are far more precise than the rotation of the planet, which varies minutely in the length of a day, and is gradually slowing down, albeit minutely.

Because of the differences in time of the Earth’s spin and the true time told by atomic clocks, occasional seconds need adding to the global timescale UTC—Leap Seconds. However, for astronomers, leap seconds are a nuisance as they need to keep track of both the Earth’s spin—astronomical time—to keep their telescopes fixed on studied objects, and UTC, which they need as atomic clock source to work out the true astronomical time.

Next year, however, a group of astronomical scientists and engineers, plan to draw attention to the forced nature of Leap Seconds at the World Radiocommunication Conference. They say that as the drift caused by not including leap seconds would take such a long time—probably over a millennia, to have any visible effect on the day, with noon gradually shifting to afternoon, there is little need for Leap Seconds.

Whether Leap Seconds remain or not, getting an accurate source of UTC time is essential for many modern technologies. With a global economy and so much trade conducted online, over continents, ensuring a single time source prevents the problems different time-zones could cause.

Making sure everybody’s clock reads the same time is also important and with many technologies millisecond accuracy to UTC is vital—such as air traffic control and international stock markets.

NTP time servers such as Galleon’s NTS 6001 GPS, which can provide millisecond accuracy using the highly precise and secure GPS signal, enable technologies and computer networks to function in perfect synchronicity to UTC, securely and without error.

Summer Solstice The Longest Day

  |   By

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

Atomic Clocks now Accurate to a Quintillionth of a Second?

  |   By

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

Differing Perceptions of Time

  |   By

When you tell somebody you’ll be an hour, ten minutes or a day, most people have a good idea how long they need to wait; however, not everybody has the same perception of time, and in fact, some people have no perception of time at all!

Scientists studying a newly discovered Amazonian tribe have found that they have no abstract concept of time, according to news reports.

The Amondawa, first contacted by the outside world in 1986, while recognising events occurring in time, do not recognise time as a separate concept, lacking the linguistic structures relating to time and space.

Not only do the Amondawa have no linguistic ability to describe time, but concepts like working throughout the night, would not be understood as time has no meaning to their lives.

While most of us in the western world tend to live by the clock, we all in fact have continuous different perceptions of time. Ever noticed how time flies when you’re having fun, or goes very slowly during times of boredom? Our time perceptions can vary greatly depending on the activities that we are undertaking.

Fighter pilots, Formula One drivers and other sportsmen often talk of “being in the zone” where time slows down. This is due to the intense concentration they are putting into their endeavours, slowing down their perceptions.

Regardless of out differing time perceptions, time itself can alter as Einstein’s Special Theory of Relativity demonstrated. Einstein suggested that gravity and intense speeds will alter time, with large planetary masses warping space-time slowing it down, while at very high speeds (close to the speed of light) space travellers could partake a journey that to observers would seem several thousands of years, but be just seconds to those travelling at such speeds.

And if Einstein’s theories seem far-fetched, it has been tested using ultra-precise atomic clocks. Atomic clocks on aeroplanes travelling around the Earth, or placed farther away from the Earth’s orbit, have minute differences to those remaining at sea-level or stationary on Earth.

Atomic clocks are useful tools for modern technologies and help to ensure that the global timescale, Universal Coordinated Time (UTC), is kept as accurate and true as possible. And you don’t need to own your own tomake sure your computer network is kept true to UTC and is hooked up to an atomic clock. NTP time servers enable all sorts of technologies to receive an atomic clock signal and keep as accurate as possible. You can even buy atomic clock wall clocks that can provide you the precise time no matter how much the day is “dragging” or “flying”.

 

 

October Launch Date for Europes Version of GPS

  |   By

The launch date for the first Galileo satellites, the European version of the Global Positioning System (GPS), has been scheduled for mid October, say the European Space Agency (ESA).

Two Galileo in-orbit validation (IOV) satellites will be launched using a modified Russian Soyus rocket this October, marking a milestone in the Galileo project’s development.

Originally scheduled for August, the delayed October launch will lift off from ESA’s spaceport in French Guiana, South America, using the latest version of the Soyuz rocket—the world’s most reliable and most used rocket in history(Soyus was the rocket that propelled both Sputnik—the first orbital satellite—and Yuri Gargarin—the first man in orbit—into space).

Galileo, a joint European initiative, is set to rival the American controlled GPS, which is controlled by the United States military. With so many technologies reliant on satellite navigation and timing signals, Europe needs its own system in case the USA decides to switch off their civilian signal during times of emergency (war and terrorist attacks such as 9/11) leaving many technologies without the crucial GPS signal.

Currently GPS not only controls the words transportation syste3ms with shipping, airliners and motorists increasingly becoming reliant on it, but GPS also provides timing signals to technologies such as NTP servers, ensuring accurate and precise time.

And the Galileo system will be good for current GPS users too, as it will be interoperable and, therefore, will increase accuracy of the 30-year-old GPS network, which is in need of upgrade.

Currently, a prototype Galileo satellite, GIOVE-B, is in orbit and has been functioning perfectly for the last three years. Onboard the satellite, as with all global navigation satellite system (GNSS) including GPS, is an atomic clock, which is used to transmit a timing signal that Earth-based navigation systems can use to triangulate accurate positioning (by using multiple satellite signals).

The atomic clock aboard GIOVE-B is currently the most accurate atomic clock in orbit, and with similar technology intended for all Galileo satellite, this is the reason why the European system will be more accurate than GPS.

These atomic clock systems are also used by NTP servers, to receive an accurate and precise form of time, which many technologies are dependent on to ensure synchronicity and accuracy, including most of the world’s computer networks.