# Amazing precision

Discussion in 'Physics' started by jpanhalt, Mar 31, 2008.

1. ### jpanhalt Thread Starter Expert

Jan 18, 2008
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I have sort of a passing interest in time measurement and wanted to share a portion of an e-mail from the director of the time division at NIST (Dr. Tom O'brian):

That is an order of magnitude better than than before. It used to be you could tell which floor in a building you were on. Now, you can tell how many steps there are.

John

2. ### Dave Retired Moderator

Nov 17, 2003
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What caught my eye was the fact they they are moving to non-caesium atoms; the last time looked at his was the NIST-F1 a couple of years back and I recall caesium being the atom of choice back then (at least it was the majority atom).

It will be interesting to see where this goes in future, the precision as a function of time is like an "Inverse" Moore's Law with precision as log-time against the year.

Dave

3. ### nomurphy AAC Fanatic!

Aug 8, 2005
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Although the concept of time is easily adopted and wonderfully useful, and very difficult to ignore, it is only an abstraction (like the sqrt -1). It doesn't really exist.

Time only exists in the mind of man (or any other reasonably aware creature or alien out there). Hence, I am really sorry to say, no time-travel but in one's imagination.

Ooops, look at the time, must be going now.

4. ### cumesoftware Senior Member

Apr 27, 2007
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The reason for such precision is that there are no mechanical parts affected by factors such as temperature, humidity, etc. The process of nuclear decaying is not affected by conditions like temperature, pressure, etc. The rate of decaying is a inverse exponential with mathematical precision, literally.

Jan 18, 2008
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May 16, 2005
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7. ### jpanhalt Thread Starter Expert

Jan 18, 2008
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That's looks like the same picture as in Wikipedia. In the US, we have WWV to synchronize to atomic time. Does BBC have that service? John

8. ### Dave Retired Moderator

Nov 17, 2003
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John, the BBC can't even get the clocks going forward and back right! IIRC last autumns roll-back was "missed" by the Beeb!

Dave