New Atomic Clock 1000 Times More Accurate 313
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."
Accurate distance too? (Score:5, Interesting)
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? (Score:2, Interesting)
upgrade (Score:2, Interesting)
Why go any further (Score:3, Interesting)
Re:Why go any further (Score:3, Interesting)
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 do this? (Score:5, Interesting)
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? (Score:5, Interesting)
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 go any further (Score:2, Interesting)
Accurate clocks causing us problems (Score:1, Interesting)
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:Why do this? (Score:5, Interesting)
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.
Re:Atomic wristwatch? (Score:3, Interesting)
Re:Atomic Clock Radio Accuracy (Score:2, Interesting)
So, can someone please tell me... (Score:3, Interesting)
I know there's an answer, please enlighten.
Cheers,
Dave
Re:Accurate clocks causing us problems (Score:3, Interesting)
Definition of precision? (Score:2, Interesting)
Re:Accurate clocks causing us problems (Score:1, Interesting)
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:Wrist Watch? (Score:3, Interesting)