DailyDirt: Calibration Time, Come On!

from the urls-we-dig-up dept

Thu, Dec 15th 2011 5:00pm — Michael Ho

Not all clocks are created equal. Some clocks lose a few seconds every month. Others are connected to cell phone towers and are constantly updating their time displays. We've come a long way from the VCRs that blink 12:00. Here are just a few articles on how we're keeping track of every minute.

Atomic clocks will be sooo "last second" when nuclear clocks start ticking. Instead of using excited electrons from a specified element to measure the passage of time, scientists will zap the nuclei of thorium atoms to create a clock that claims to drift by about 1 second in 200 billion years. [url]
NIST has an interesting website on the history of time keeping. NIST also broadcasts shortwave signals and offers a phone-based service to deliver the current time within an accuracy of a few milliseconds. [url]
[Warning: pdf link] In January 2012, there could be a redefined version of Coordinated Universal Time that eliminates any requirement to keep our time systems synchronized to the Earth's rotation -- and ditching the "leap second" among other artifacts. Computer: "Captain's log, stardate 41153.7. Our destination is planet..." [url]
To discover more interesting science-related stuff, check out what's currently floating around the StumbleUpon universe. [url]

By the way, StumbleUpon can recommend some good Techdirt articles, too.

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Filed Under: clocks, leap seconds, nuclear clock, stardate, time
Companies: nist

10 Comments

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mischab1, 15 Dec 2011 @ 5:24pm

You can't read the full American Scientist article without paying. :(

The content you've requested is available without charge only to active Sigma Xi members and affiliates
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Lawrence D'Oliveiro, 15 Dec 2011 @ 6:00pm

Stardates
I�ve proposed a definition of stardates as a number of days (accurate to tenths of a day) from 00:00:00 1st January 1970 UTC. You can compute it with this command:

bc <<<"scale = 1; ($(date +%s)) / 86400"

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Michael Ho (profile), 15 Dec 2011 @ 6:03pm

Re:
oops. sorry. I'll fix that in a bit..

Try here for a pdf:
http://arxiv.org/pdf/1106.3141v1
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abc gum, 15 Dec 2011 @ 7:56pm

"there could be a redefined version of Coordinated Universal Time that eliminates any requirement to keep our time systems synchronized to the Earth's rotation"

This sort of thinking is rather short sighted and will probably make the pencil neck MBAs happy, it has definitely caused a stir in the scientific fields. For some, the immediate problem will be tracking divergent time systems, others will not have a problem at all for many years. Eventually, Christmas in the northern hemisphere will no longer occur in winter. Not sure how Santa feels about that. There are several suggestions about how this should be addressed - not sure if any make more sense than simply staying with the system presently in place.
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Anonymous Coward, 15 Dec 2011 @ 8:58pm

Re:
Yeah, that is always the problem: "we can have a system without all the artifacts and tweaks needed to calibrate it to the observed day" sounds great and good and swell - right up until you are telling people that noon is now at sunset and the winter solstice is in May. I understand that sciency types would really like a simple time system - I would like a simple time system - but ultimately, timekeeping is about day-to-day concerns, and no one cares that this is Second 1490384512897124956503250325681025863405 since the Adoption of Regular Time and leap seconds/minutes/hours/days are a thing of hte past, if it means they have to go to bed in the middle of the afternoon because that is 0:00 UTC now and work starts in 8 hours in the pitch dark.
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Violated (profile), 15 Dec 2011 @ 9:58pm

I presume their new clock is the caesium fountain clock. Each tick is the time it takes to go up and then down.

Nice but the best time keepers in our Universe are the pulsar stars that make great time keepers through their regular rapid rotations.
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Lawrence D'Oliveiro, 16 Dec 2011 @ 1:09am

Re: ... the best time keepers in our Universe are the pulsar stars that make great time keepers through their regular rapid rotations.
No they�re not. They are all perceptibly slowing down.

Guess how we measure that?
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BentFranklin (profile), 16 Dec 2011 @ 7:51am

The March 2011 earthquake in Japan caused earth's sidereal day to decrease by some milliseconds. Should the time standards be adjusted after every earthquake? How about when the ice caps melt and rotation slows down by a lot?

It's complicated, but I still like noon being the exact time when the sun is highest in the sky.
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Michael Ho (profile), 16 Dec 2011 @ 1:23pm

Re:
I think we ought to try to accelerate the Earth's rotation in order for it to match atomic clocks... :P
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Anonymous Coward, 18 Dec 2011 @ 1:40am

Leap Seconds
Proposals to somehow define leap seconds out of existence are misguided. The earth's rotation is slowing down. That is a physical fact that we humans are powerless to change. So the solar second is gradually getting longer. The UTC second was based on the mean solar second of a past year and is constant. It needs to be constant to avoid yearly revisions of a whole bunch of physical constants. Navigators and astronomers like to use UTC and want it kept close to solar time, not drifting off. Thus leap seconds are inevitable. Weenies who are not coping with leap seconds need to toughen up and cope. Get the software fixed and stop moaning.
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