View Full Version : Super accurate clock


TWT
12th Mar 2012, 09:09
Single ion clock 100 times more accurate than atomic | Space, Military and Medicine | News.com.au (http://www.news.com.au/technology/sci-tech/nucelar-clock-100-times-more-accurate-than-atomic-clock/story-fn5fsgyc-1226297068083)

There's some very clever people out there !



Sallyann1234
12th Mar 2012, 11:21
The scientists said the nuclear clock’s oscillation rate was almost completely unaffected by any external interference from other forces.
So I can throw away my books on quantum theory.

Cacophonix
12th Mar 2012, 11:44
So I can throw away my books on quantum theory.


Probably not (where is Werner Heisenberg when you need him)? The traditional ion trap uses an indirect mode of RF frequency measurement resulting from the movement of ions between diffent charge states (quanta) in the trap. The ions themselves aren't directly measured with respect to position and velocity so our "measurement" does not disturb the system.

The system noted above is likely to be a derivation of the setup noted in the IEEE document linked below but await a correction with some interest.

http://www.iontrap.umd.edu/publications/archive/IEEETUFFC_44_344_fisk_freq_review.pdf

Caco

G-CPTN
12th Mar 2012, 12:31
What effect on the accuracy of time measurement does events like the Japanese earthquake have?
The earthquake shifted the Earth's axis by estimates of between 10 cm (4 in) and 25 cm (10 in).
This deviation led to a number of small planetary changes, including the length of a day, the tilt of the Earth, and the Chandler wobble.

The speed of the Earth's rotation increased, shortening the day by 1.8 microseconds due to the redistribution of Earth's mass.

The axial shift was caused by the redistribution of mass on the Earth's surface, which changed the planet's moment of inertia.
Because of conservation of angular momentum, such changes of inertia result in small changes to the Earth's rate of rotation.

These are expected changes for an earthquake of this magnitude.From:- 2011 T (http://en.wikipedia.org/wiki/2011_T%C5%8Dhoku_earthquake_and_tsunami#Geophysical_effects)

bnt
12th Mar 2012, 13:59
What effect on the accuracy of time measurement does events like the Japanese earthquake have?
From:- 2011 T (http://en.wikipedia.org/wiki/2011_T%C5%8Dhoku_earthquake_and_tsunami#Geophysical_effects)
I suppose the point is that clocks can be extremely precise, but the Earth ... can't. :8

(I'm using the word "precise" in its scientific meaning, relating to consistency: it is possible to be precise but inaccurate, like a target shooter who puts all his shots in the same place, far from the bullseye. "Accurate" therefore implies a target against which one can measure accuracy, but when it comes to measuring the earth (the original geo-metry), the target is moving ... so how can we decide whether a clock is accurate, or not? This is where astronomers start looking to the stars for a more stable reference point.)

flying lid
12th Mar 2012, 19:31
No ion clocks when George was a lad !!

George Stephenson is reputed to have made this sundial with his son, Robert. One of the few things they built not to run on steam !!

http://upload.wikimedia.org/wikipedia/commons/6/65/George_Stephenson_Sun_Dial.jpg

Lid

Slasher
13th Mar 2012, 05:22
From CPTN's source -

The quake moved portions of northeastern Japan by as much
as 2.4 m (7.9 ft) closer to North America.

...Guess that explains why I landed on NRT's 36L 2.4m to the
left last time I was there. Banged it on too after rounding out
at the normal height so the elevation's probably risen as well.

Least that was the excuse I gave the 400hr FO...!

ShyTorque
13th Mar 2012, 14:12
That's really useful.

In 14 billion years time I'll be able to ensure that I'm never more than 1/20th of a second late for work.

teeteringhead
13th Mar 2012, 15:07
I say I say I say!

Werner Heisenberg was late for work, so was trying to make up time on an empty road. Shame about the speed cop (SC).

The interview goes:

SC: Excuse me Sir, do you know how fast you were going?

WH: No officer, but I knew exactly where I was!

Boom boom!

.... well, it's the only quantum physics joke I know .........

ShyTorque
13th Mar 2012, 19:24
All mine are only O level physics.... ;)