New Atomic Clock 1000 Times More Accurate

stevelinton writes "The UK National Physical Laboratory has a new atomic clock potentially 1000 times more accurate than current cesium clocks: to within 1 second in about 30 billion years! This could lead quite soon to a new definition of the second, and in a while to improved resolution in GPS successor systems. More interestingly, there are theories that some of the universe's fundamental dimensionless constants may have changed by a parts in a million over the last 10 billion years or so. These clocks are so accurate that they should be able to detect these changes over a year or two."

Comments

Accurate distance too?

[Ckwop]

Great.. now I can measure measure how late the train is to an accuracy of a few attoseconds. hehe

The great thing about getting more accurate timing is that it should allow you to measure distances with the same accuracy. I think that by shining two different coloured lasers against a mirror and measuring the beats in the interference pattern of the returned beam it should be possible to measure a metre very exactly.

Anyone know if this is garbage or does more accurate time mean more accurate distance.

Simon.

Why do this?

[zerman]

I don't mean to be offensive, but is there any real point to this? How much accurate does the clock really have to be? What is the point of having a clock that is this accurate? We pour millions of dollars into this type of thing. So what? Even if we did need the accuracy (which we don't) we would never have it because the accuracy bottleneck would always be transporting the signal to wherever it's needed. Can anyone think of one good example where this clock serves any real purpose, and the old cesium one wasn't good enough?

Re:Why do this?

[maeka]

The accuracy of the clocks is a small factor in real-time GPS accuracy.

Ionospheric delay plays a much larger role. Survey-grade receivers use both the L1 and the L2 bands in an attempt to better model this delay. Ionospheric delay is frequency-dependent and impacts on the L1 and L2 signals by a differing amounts.

Multipath plays a role also, not as big as the ionosphere, but still larger than the accuracy of the clocks on the GPS satellites.

Re:Why do this?

[Misanthropy]

I was thinking the same thing until I actually read the article.

An answer from the article that affects everyone and not just super geek physicists:

Navigation on earth - based on a cluster of orbiting satellites - is limited by the accuracy of the atomic clock on each satellite. A series of calculations can get millimetre accuracy on the position of a stationary object, but for moving objects like cars and planes the accuracy is no better than a few metres. Only by making faster measurements can this accuracy be improved, something enabled by a more accurate definition of the second.
...
"That is why GPS is not yet good enough to land a passenger aircraft on its own," Prof Gill says.


Pretty cool stuff.

Re:Why do this?

[Tony-A]

Can anyone think of one good example where this clock serves any real purpose

Predicting earthquakes and volcanos.
Finding oil, gas, mineral deposits.
Hardly automatic, but attaining extreme accuracy cheaply can only help.

With a few high precision clocks broadcasting, it is possible to triangulate position precisely and hence the delay time. Precision in timing translates into precision in distance. If stuff is moving inches per decade or century, it would be interesting to know exactly how that movement is accomplished.

upgrade

[Barsema]

I guess this guy will need an upgrade.

Why go any further

[suso]

1 second every 30 billion years? That's more than twice as long as the age of the universe. So why then would atomic clock developers need to go any further?

Re:Why go any further

[metlin]

Because you need precise measurements for things other than needing to know what the time is.

And these clocks are not just used as solar clocks, they are calibrated to be sidereal clocks too - to know the movement of the stars and the like.

Imagine you are conducting a particle collision experiment in a tunnel - the particles are almost travelling at the speed of light, and they'd cover the distance of your tunnel almost instantaneously. You would need to measure this as precisely as you can. The more this measurement is, the more precisely we can calculate how the data from other particle collisions in the Universe (from cosmic rays, for instance) are - letting us know how the Universe has changed/is changing.

There are several applications of it - most of it of interest to physicists only, ofcourse.

Re:Why go any further

[ThJ]

Accuracy and precision are not the same, as outlined in other replies to this article. The less drift you have over time, the more accurate it is. The higher number of ticks you have pr second, the more precise it is. It would be interesting to know the number of ticks/second these things can do, though...

Accurate clocks causing us problems

[caseih]

Getting more and more accurate clocks is causing a very interesting (and potentially deadly) problem. Every year, the earth rotates slower and slower. I believe that currently we add a couple of leap seconds every year. Unfortunately the world has not completely standardized on when and how these leaps seconds are to be inserted. This leads to a problem where applications that require very accurate time (say airplanes) can potentially be different by a number of seconds. If airplane one has already adjusted time, airplane B has not, but the controller has, then the controller may order a plane to move to a certain position at a certain time which could cause an accident. This is not unlike the great train schedule disasters of the 1800s before time zones were standardized. There has already been one near miss that I've heard of because of this leap second problem.

In the past this wasn't a problem because timepieces had to be adjusted regularly. Obviously having accurate clocks is a good idea, so long as we can have a world standard for adjusting them.

Re:Accurate clocks causing us problems

[certsoft]

As the other post has noted, leap second insertion is standardized. In addition, there hasn't been a leap second since December 1998, and there will be none for at least the rest of this year.

Re:Accurate clocks causing us problems

[Anonymous Coward]

There is so much misinformation in the parent post that it should be modded into oblivion. It must be a troll, right?

First of all, as other posts have noted, leap seconds are completely standardized and announced months in advance. There haven't been any since 1998.

Second of all, it does't matter for things like airplane navigation; the GPS timescale, for example, has no leap seconds. There's a timescale called TAI which is an atomic timescale that has no leap seconds and thus always differs from UTC by an integral number of seconds. The GPS timescale is similar.

Third of all -- and now, I'll speak as a licensed pilot and not a researcher who did a PhD in time synchronization -- the thought that two airplanes could collide due to a 1-second time synchronization error is rather silly. I can't think of anything in the air traffic control system that could possibly lead to such an event. Human controllers direct airplanes by watching them on the screen, not planning their exact arrival times down to one second, and in any case nothing is done with a 1-second margin of error!

And, finally, the fact that we had leap seconds didn't indicate that the world was "slowing down" but rather that at some point in the past, it DID slow down and then was turning at a slower (but possibly still constant) rate that was slower than the rate when we first established the atomic timescale. The fact that the leap seconds have stopped for 6 years, if anything, means the earth *accelerated* some time in the past few years.

Re:Atomic wristwatch?

[deglr6328]

This brings up an interesting point dosent it? How can a clock accurate to one in 10^15 or one second in 30 billion years ever be truly useful to that accuracy? Wouldn't simply walking the thing down the hall to the next lab introduce unacceptable error in the clock due to the time dilation involved?

Re:Atomic Clock Radio Accuracy

[anno1602]

No. Radio-controlled clocks are not that accurate. Keep in mind that they are not actually constantly synchronized with the national atomic clock, they are running on a standard quartz and reset themselves every time they successfully receive a time signal. Besides, a factor would also be the results of the signal being reflected all over the place, potentially traveling a much longer path than a straight line - and, due to moving objects such as cars that might be in the way, not always the same paths. Besides, it would be impossible - ntp uses two-way communication to measure the lag, while radio controlled clocks can't phone home to the atomic clock.

So, can someone please tell me...

[WasterDave]

This has been bugging me for years. There's this spurious "atomic clocks are accurate to 1 second within a million years" thing - so how the hell to you measure it? And if you've got a more accurate way of measuring time, why not just use *that* as the clock.

I know there's an answer, please enlighten.

Cheers,
Dave

Definition of precision?

[yodaj007]

If some clock is held to be the standard, how can they say that its off by so many seconds every so many thousand years? By what standard is the standard held to?

Re:Wrist Watch?

[Detritus]

They are nowhere near as accurate as an atomic clock. Even with a lab grade radio clock, large amounts of error are introduced by the propagation delay of the radio signal, which isn't constant. Consumer grade radio clocks are useless for any serious applications. They use cheap quartz crystal oscillators and compensate for errors by resetting the clock once a day.