Posted on 04/03/2014 6:09:54 PM PDT by zeestephen
"It has an accuracy that's equivalent to about one second in 300 million years." - "If we've learned anything in the last 60 years of building atomic clocks, we've learned that every time we build a better clock, somebody comes up with a use for it that you couldn't have foreseen."
(Excerpt) Read more at nbcnews.com ...
I’ve noticed that the time at “Time.gov” is consistently 15 seconds faster than the clock on my computer.
Is that a network issue or something involving leap seconds?
Well, kind of. Except that NIST-F2 is so accurate that the lag time of the signal going through the servers and pipelines to get to your computer throws the actual timing signal off by orders of magnitude, thereby destroying it's actual accuracy for your particular use.
It's like when they had to cut all of the wires in Fat Man to exactly the same length, so that the detonation signal, traveling at near light-speed, would reach the detonators at the precision level of synchronization that they needed in order to trigger the nuclear warhead.
There's timing, and then there's timing. LOL!
“we saw the hands go around and around really fast for 15 minutes and then reset itself at the exact right time.”
Normal behavior. The “atomic” clocks for home use are actually radio controlled clocks...they get signals from NIST via very low frequency radio. Most of them re-calibrate once a day. I have 2 analog versions that do more or less what you described at about 1:30 am local time every day.
This is true.
But an important use of seconds is to tell human local time. As in when does the sun rise, when is it noon, when is sunset?
Those times all depend on the earth's rotation and its orbital period around the sun. Neither of those take orders from the Cesium atom.
Hence, the leap second, a hack to allow the real Cesium second to be used for measurements that actually need its precision, while still allowing high noon to occur precisely when it should.
My Casio wristwatch does such as that, twice a year. More often if I travel and need to change the timezone offset.
First, the second hand goes to the noon position. Then the minute and hour hands move to the new position in a sweeping motion. Then the second hand moves into place. And then back to normal: tick, tick, tick ...
Of course, the hour, minute, and second hand are all just for display. The actual time is just a number it maintains internally. Every morning, the watch tunes into NIST's atomic clock radio station and sets itself to the time being broadcast, including whether DST is in effect.
So, I don't have to do anything unless I change timezones. Not bad for ~$100 in 2004. Did I mention, it's solar powered? No need to change batteries.
But I'm jealous. I've heard there is a watch that sets itself via GPS. Since it thereby knows not only the exact time but also where it is, there is no need for the wearer to fiddle with timezones. Nice.
No, she does not.
Do you still have to adjust it twice a year for Daylight Savings Time?
Does anybody really know what time it is?
lol
Does anybody really care? ;-P
Thanks for the Grace Hopper memory. I sat in one of her time and technology lectures at the Naval Academy as a midshipmen some 35 years ago. I still use the nano-second = ~12” wire analogy to this day. :)
Is that a network issue or something involving leap seconds?
It might be that whatever your computer is using for a time server is slow.
Or it could be your clock is 15 seconds slow.
there are several good NTP programs that will keep your time in sync using a standard network protocol. I think they have links for some reliable ones at the Directorate of Time. (yes, there really is such a place). Would that not be the coolest job to have? I'd love to be able to hand out business cards and say, "yes, I am the Directorate of Time".
Meh. Call me when it is available in wristwatch form.
It has never done that again in 7 years.
The hands both moved continuously as fast as they could for fifteen minutes without stopping. The clock only did this twice. Once the day she died the other when the women from the funeral parlor came over to discuss the plans for the funeral.
I you are already convinced it was a ghost, why did you ask?
I am not convinced but that other post says it does that for her twice a year. Ours did not. It has never done it again.
trying to see if anyone knows of this way it can do this, but realistically. It hasn’t done it all the time or twice a year. That is what was so puzzling.
I was injecting a little humor, but others take time-keeping way too serious. After I retired, I stopped using clocks to run my life. I really don't know what time it is, nor do I care with most daily matters. I watch the seasons for maintaining my gardens. Seconds, minutes, heck even days of the week matter little to me. A few things come up like doctor appointments or parking meters, but most time-keeping is ignored. After watching the clock all my working life and being stressed, I've come to enjoy not caring what time it is!
I have both digital and analog “atomic” clocks. The analog one does what you described twice annually plus any other is time its off. A dead battery is usually cause for the other times.
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