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New Super-Accurate Atomic Clock Tells Time Like No Other
NBC News ^ | 03 April 2014 | James Eng

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 ...


TOPICS: Science
KEYWORDS: atomicclock; clock; oscillations; physics; time
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1 posted on 04/03/2014 6:09:54 PM PDT by zeestephen
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To: zeestephen
C

To measure lots of time in nanoseconds, get a longer string

2 posted on 04/03/2014 6:13:26 PM PDT by bert ((K.E. N.P. N.C. +12 ..... History is a process, not an event)
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To: zeestephen

Measuring time is at the base of Science.


3 posted on 04/03/2014 6:13:42 PM PDT by Paladin2
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To: zeestephen
“NIST-F2 is now an official source of time for the United States — it has an accuracy that's equivalent to about one second in 300 million years,”

What difference does it make? Mother nature changes the time with each major earthquake. The last few big earthquakes speeded up the rotation of the Earth and knocked seconds off the clock. Which means people still have to adjust clocks - even super-accurate atomic clocks.

4 posted on 04/03/2014 6:17:44 PM PDT by roadcat
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To: zeestephen

Right 3 times a day?


5 posted on 04/03/2014 6:19:26 PM PDT by Scrambler Bob ("The Pen" has a nice ring to it, kind of like "Graybar Hotel")
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To: roadcat
If the rotation of the earth speeds up, a second will still be a second (only difference is in relativity which would be almost immeasurable with such a small increase in rotational sped)

What a clock like this is good for is calibrating scientific equipment, measuring the speed of atomic particles, possibly the expansion of the universe, Doppler effect etc.

6 posted on 04/03/2014 6:21:13 PM PDT by LukeL
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To: zeestephen
From Wikipedia:

"In March 2008, physicists at NIST described a quantum logic clock based on individual ions of beryllium and aluminium. This clock was compared to NIST's mercury ion clock. These were the most accurate clocks that had been constructed, with neither clock gaining nor losing time at a rate that would exceed a second in over a billion years. In February 2010, NIST physicists described a second, enhanced version of the quantum logic clock based on individual ions of magnesium and aluminium. Considered the world's most precise clock, it offers more than twice the precision of the original."

7 posted on 04/03/2014 6:22:17 PM PDT by Steely Tom (How do you feel about robbing Peter's robot?)
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To: zeestephen

Glad I was 0.00000000000000000000000000000001 seconds earlier otherwise I’d have been late fro my hair appointment.


8 posted on 04/03/2014 6:28:49 PM PDT by SkyDancer (I Believe In The Law Until It Intereferes With Justice. And Pay Your Liberty Tax Citizen.)
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To: roadcat
The definition of a second has nothing to do with the rotation of the Earth:

The second is the duration of 9 192 631 770 periods of the radiation corresponding to the transition between the two hyperfine levels of the ground state of the cesium 133 atom.

9 posted on 04/03/2014 6:42:18 PM PDT by DManA
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To: LukeL

I was trying to be humorous. But I differ with you about a second. A 60th of a minute, and a minute is a 60th of an hour, the hour being a 24th of a day in which the Earth rotates once relative to the Sun’s position. So if the rotation of the Earth speeds up, so does a second. Minutely. Earthquakes, tides and wind all constantly alter the Earth’s rotational speed, but only in microseconds. Over long periods of time, it adds up but only as milliseconds. But a second can alter in duration.


10 posted on 04/03/2014 6:45:42 PM PDT by roadcat
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To: zeestephen

I’ve got a clock on the iPad that is down to around 1/1000 of a second!


11 posted on 04/03/2014 6:46:27 PM PDT by Star Traveler (Remember to keep the Messiah of Israel in the One-World Government that we look forward to coming)
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To: zeestephen

I want one.


12 posted on 04/03/2014 6:47:08 PM PDT by BunnySlippers (I LOVE BULL MARKETS . . .)
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To: zeestephen

At last, a clock that can measure my period of mourning for Teddy Kennedy.


13 posted on 04/03/2014 6:49:29 PM PDT by Billthedrill
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To: DManA

During my lifetime, the definition of a second had everything to do with the rotation of the Earth, as it did for millenia. Scientists redefined it in 1967. I’m a traditionalist.


14 posted on 04/03/2014 6:49:42 PM PDT by roadcat
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To: roadcat

You must be many moons old.


15 posted on 04/03/2014 6:52:06 PM PDT by DManA
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To: bert

So when the sun expands into a red giant and the earth is engulfed in a firey corona and turned into a cinder, this thing will be more than a minute off?


16 posted on 04/03/2014 6:52:17 PM PDT by Smedley (It's a sad day for American capitalism when a man can't fly a midget on a kite over Central Park)
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To: Steely Tom
These were the most accurate clocks that had been constructed, with neither clock gaining nor losing time at a rate that would exceed a second in over a billion years.

The clock in the article is a civilian NIST clock. Apparently scientific clocks or ones used by the military are much better.

17 posted on 04/03/2014 6:52:48 PM PDT by Moonman62 (The US has become a government with a country, rather than a country with a government.)
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To: zeestephen

My sister owned an atomic clock and the day she died and we came home from the hospital we saw the hands go around and around really fast for 15 minutes and then reset itself at the exact right time.

Anyone know if this is something an atomic clock can do, because otherwise we assumed it was my sister saying goodbye.?


18 posted on 04/03/2014 6:53:44 PM PDT by Beowulf9
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To: Billthedrill

love it!


19 posted on 04/03/2014 6:57:08 PM PDT by lonestar (It takes a village of idiots to elect a village idiot.)
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To: bert

RADM Hopper!


20 posted on 04/03/2014 6:58:35 PM PDT by rabidralph
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21 posted on 04/03/2014 6:58:49 PM PDT by dsrtsage (One half of all people have below average IQ. In the US the number is 54%)
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To: Billthedrill

awesome. :) actually DID LOL.


22 posted on 04/03/2014 6:59:28 PM PDT by ZinGirl (kids in college....can't afford a tagline right now)
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To: Billthedrill

You got my vote for post of the day!


23 posted on 04/03/2014 6:59:36 PM PDT by CrazyIvan (Obama phones= Bread and circuits.)
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To: zeestephen

Next time, on This Old Clock....


24 posted on 04/03/2014 6:59:52 PM PDT by Secret Agent Man (Gone Galt; Not averse to Going Bronson.)
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To: Billthedrill

I miss ol “Waitress Sandwich” Teddy.

The waitress, does not. ;)


25 posted on 04/03/2014 7:02:13 PM PDT by Secret Agent Man (Gone Galt; Not averse to Going Bronson.)
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To: roadcat
The last few big earthquakes speeded up the rotation of the Earth and knocked seconds off the clock.

Stop Global Speeding!!!

26 posted on 04/03/2014 7:04:00 PM PDT by Arthur McGowan
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To: zeestephen

I am mathematically challenged when it concerns time. I was taught that time is infinite and that infinity divided by anything equals infinity.

So isn’t a nanosecond infinite?


27 posted on 04/03/2014 7:10:19 PM PDT by granite (The heart of the wise inclines to the right, but the heart of the fool to the left - Ecclest 10:2)
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To: Arthur McGowan
Stop Global Speeding!!!

Great something new for the libbies to whine about and blame Conservatives on.

28 posted on 04/03/2014 7:11:03 PM PDT by softwarecreator
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To: bert
a friend of mine still has a nanosecond
29 posted on 04/03/2014 7:16:40 PM PDT by Chode (Stand UP and Be Counted, or line up and be numbered - *DTOM* -vvv- NO Pity for the LAZY - 86-44)
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To: zeestephen

I think this is rather neat, myself. My wall clock gets the time signal from WWVB, which is now apparently tied in to the new NIST-F2. If that’s true, then I also have a very accurate clock in my own home.


30 posted on 04/03/2014 7:19:47 PM PDT by hoagy62 ("Tyranny, like hell, is not easily conquered..."-Thomas Paine. 1776)
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To: DManA

****************************************************

The definition of a second has nothing to do with the rotation of the Earth:
The second is the duration of 9 192 631 770 periods of the radiation corresponding to the transition between the two hyperfine levels of the ground state of the cesium 133 atom.

****************************************************

So we have only been measuring seconds since we were able to figure out the transition in cesium 133 atoms?

I did not know that.


31 posted on 04/03/2014 7:20:25 PM PDT by SolidRedState (I used to think bizarro world was a fiction.)
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To: bert
*** To measure lots of time in nanoseconds, get a longer string ***

Don't you mean, nanoo nanoo seconds?


32 posted on 04/03/2014 7:26:32 PM PDT by SolidRedState (I used to think bizarro world was a fiction.)
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To: roadcat

No, the second is a physical unit, and hours and days are fixed multiples of it. To keep civil time from drifting away from meridian time, “leap seconds” are periodically added to calendar time, as needed.

This is an “intercalation”, neither the day preceding nor the day following is changed in length. The leap second is inserted between them.


33 posted on 04/03/2014 7:27:51 PM PDT by dr_lew
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To: SolidRedState
Before atomic clocks there was no way to keep time more accurately than astronomical standards allowed.

According to the website, Astronomical Time Keeping, it was realized around 1930 that the earth's rotation rate varied somewhat. The earth's solar orbit is more stable, and was made the basis for the second in 1957. This standard was called Ephemeris Time, but it was very difficult to use because its calibration depended on observations of the stars and planets spread over years.

The article also points out that even atomic clocks are affected by the motion and gravitation of the earth, so it's impossible to entirely remove astronomical considerations from a standard time scale.

34 posted on 04/03/2014 7:47:44 PM PDT by dr_lew
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To: dr_lew; roadcat

And does not the theory of relativity tell us that time can be altered from an observer viewpoint but that only the speed of light is a constant (in a vacuum)?


35 posted on 04/03/2014 8:19:32 PM PDT by BipolarBob
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To: roadcat
What difference does it make? Mother nature changes the time with each major earthquake. The last few big earthquakes speeded up the rotation of the Earth and knocked seconds off the clock. Which means people still have to adjust clocks - even super-accurate atomic clocks.

Clocks like this aren't used to keep time. They are used to measure it. The more accurate the clock, the smaller increments that can be measured accurately. Atomic clocks are useful in a number of application where hyper-accurate measures of intervals are required.

 

36 posted on 04/03/2014 8:21:38 PM PDT by zeugma (Is it evil of me to teach my bird to say "here kitty, kitty"?)
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To: zeestephen

I an hardly wait for the Super-Duper Atomic clock.


37 posted on 04/03/2014 8:24:37 PM PDT by MaxMax (Pay Attention and you'll be pissed off too! FIRE BOEHNER, NOW!)
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To: SolidRedState

The definition changed as we were able to isolate phenomena that weren’t affected by gravity etc. It’s called progress.


38 posted on 04/03/2014 8:26:23 PM PDT by DManA
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To: dr_lew
This is an “intercalation”, neither the day preceding nor the day following is changed in length. The leap second is inserted between them.

Speaking of which, if you really want to make your head hurt, read some of the articles published about how to standardize the keeping of time on computers. Adding and removing of leap seconds can be a big deal to processes that need accurate coordinated time across great distances, for logging, control and other purposes. Exactly how you define your Epoch beginning, and how you calculate an exact time from that Epoch date until today is really, really complex.

For instance, unix computers generally define the epoch as having begun at midnight, Jan. 1, 1970 UTC (microsoft uses 1/1/80 I think). Now, there have been a number of leap seconds added (and some subtracted) from that time until today. The time maintained on your computer is a count of the number of seconds since that date. I looked up the current time in seconds since the epoch and it shows it as being 1396582545. OK, now the question is, have the leap seconds been added to that number or not? Since 1972 there have been 25 leap seconds added to the calendar.

So, if I run that integer above through the unix 'date' command to determine what time it represents it shows the following:

$ date --date='@1396582545'
Thu Apr  3 22:35:45 CDT 2014
 

So, the question of whether leap seconds are included in that calculation is actually relevant. If they have not been, then the actual time represented by the number 1396582545 should have been Thu Apr  3 22:36:10 CDT 2014

Is it important? Well, if you're attempting to troubleshoot a network issue and are attempting to correlate logs from multiple systems that may not all implement the same algorythm for calculating that date, it could be relavant. A lot can happen in 25 seconds on a modern computer network.

The method that I'd propose to eliminate the uncertainty would be to implement a lookup table that contains a list of leap seconds similar to the following:

1961 JAN  1 =JD 2437300.5  TAI-UTC=   1.4228180 S + (MJD - 37300.) X 0.001296 S
 1961 AUG  1 =JD 2437512.5  TAI-UTC=   1.3728180 S + (MJD - 37300.) X 0.001296 S
 1962 JAN  1 =JD 2437665.5  TAI-UTC=   1.8458580 S + (MJD - 37665.) X 0.0011232S
 1963 NOV  1 =JD 2438334.5  TAI-UTC=   1.9458580 S + (MJD - 37665.) X 0.0011232S
 1964 JAN  1 =JD 2438395.5  TAI-UTC=   3.2401300 S + (MJD - 38761.) X 0.001296 S
 1964 APR  1 =JD 2438486.5  TAI-UTC=   3.3401300 S + (MJD - 38761.) X 0.001296 S
 1964 SEP  1 =JD 2438639.5  TAI-UTC=   3.4401300 S + (MJD - 38761.) X 0.001296 S
 1965 JAN  1 =JD 2438761.5  TAI-UTC=   3.5401300 S + (MJD - 38761.) X 0.001296 S
 1965 MAR  1 =JD 2438820.5  TAI-UTC=   3.6401300 S + (MJD - 38761.) X 0.001296 S
 1965 JUL  1 =JD 2438942.5  TAI-UTC=   3.7401300 S + (MJD - 38761.) X 0.001296 S
 1965 SEP  1 =JD 2439004.5  TAI-UTC=   3.8401300 S + (MJD - 38761.) X 0.001296 S
 1966 JAN  1 =JD 2439126.5  TAI-UTC=   4.3131700 S + (MJD - 39126.) X 0.002592 S
 1968 FEB  1 =JD 2439887.5  TAI-UTC=   4.2131700 S + (MJD - 39126.) X 0.002592 S
 1972 JAN  1 =JD 2441317.5  TAI-UTC=  10.0       S + (MJD - 41317.) X 0.0      S
 1972 JUL  1 =JD 2441499.5  TAI-UTC=  11.0       S + (MJD - 41317.) X 0.0      S
 1973 JAN  1 =JD 2441683.5  TAI-UTC=  12.0       S + (MJD - 41317.) X 0.0      S
 1974 JAN  1 =JD 2442048.5  TAI-UTC=  13.0       S + (MJD - 41317.) X 0.0      S
 1975 JAN  1 =JD 2442413.5  TAI-UTC=  14.0       S + (MJD - 41317.) X 0.0      S
 1976 JAN  1 =JD 2442778.5  TAI-UTC=  15.0       S + (MJD - 41317.) X 0.0      S
 1977 JAN  1 =JD 2443144.5  TAI-UTC=  16.0       S + (MJD - 41317.) X 0.0      S
 1978 JAN  1 =JD 2443509.5  TAI-UTC=  17.0       S + (MJD - 41317.) X 0.0      S
 1979 JAN  1 =JD 2443874.5  TAI-UTC=  18.0       S + (MJD - 41317.) X 0.0      S
 1980 JAN  1 =JD 2444239.5  TAI-UTC=  19.0       S + (MJD - 41317.) X 0.0      S
 1981 JUL  1 =JD 2444786.5  TAI-UTC=  20.0       S + (MJD - 41317.) X 0.0      S
 1982 JUL  1 =JD 2445151.5  TAI-UTC=  21.0       S + (MJD - 41317.) X 0.0      S
 1983 JUL  1 =JD 2445516.5  TAI-UTC=  22.0       S + (MJD - 41317.) X 0.0      S
 1985 JUL  1 =JD 2446247.5  TAI-UTC=  23.0       S + (MJD - 41317.) X 0.0      S
 1988 JAN  1 =JD 2447161.5  TAI-UTC=  24.0       S + (MJD - 41317.) X 0.0      S
 1990 JAN  1 =JD 2447892.5  TAI-UTC=  25.0       S + (MJD - 41317.) X 0.0      S
 1991 JAN  1 =JD 2448257.5  TAI-UTC=  26.0       S + (MJD - 41317.) X 0.0      S
 1992 JUL  1 =JD 2448804.5  TAI-UTC=  27.0       S + (MJD - 41317.) X 0.0      S
 1993 JUL  1 =JD 2449169.5  TAI-UTC=  28.0       S + (MJD - 41317.) X 0.0      S
 1994 JUL  1 =JD 2449534.5  TAI-UTC=  29.0       S + (MJD - 41317.) X 0.0      S
 1996 JAN  1 =JD 2450083.5  TAI-UTC=  30.0       S + (MJD - 41317.) X 0.0      S
 1997 JUL  1 =JD 2450630.5  TAI-UTC=  31.0       S + (MJD - 41317.) X 0.0      S
 1999 JAN  1 =JD 2451179.5  TAI-UTC=  32.0       S + (MJD - 41317.) X 0.0      S
 2006 JAN  1 =JD 2453736.5  TAI-UTC=  33.0       S + (MJD - 41317.) X 0.0      S
 2009 JAN  1 =JD 2454832.5  TAI-UTC=  34.0       S + (MJD - 41317.) X 0.0      S
 2012 JUL  1 =JD 2456109.5  TAI-UTC=  35.0       S + (MJD - 41317.) X 0.0      S

The date to be displayed can therefore be accurately displayed to the user because it could be calculated accurately on the fly.

Yeah, most people don't care about stuff like this, but it is important for engineers to understand that there are multiple standards of time out there. GPS does NOT use leap seconds. This is very important for GPS recievers to know.

Here's a blurb I pulled from another page...(USNO)

International Atomic Time (TAI)  is a statistical atomic time scale based on a large number of clocks operating at standards laboratories around the world that is maintained by  the Bureau International des Poids et Mesures; its unit interval is exactly one SI second at sea level. The origin of TAI is such that UT1-TAI is approximately 0 (zero) on January 1, 1958. TAI is not adjusted for leap seconds.  It is recommended by the BIPM that systems which cannot handle leapseconds use TAI instead.

Coordinated Universal Time (UTC) is defined by the CCIR Recommendation 460-4 (1986). It differs from TAI by the total number of leap seconds, so that UT1-UTC stays smaller than 0.9s in absolute value.   The decision to introduce a leap second in UTC is the responsibility of the International Earth Rotation Service (IERS). According to the CCIR Recommendation, first preference is given to the opportunities at the end of December and June, and second preference to those at the end of March and September. Since the system was introduced in 1972, only dates in June and December have been used.  TAI is expressed in terms of UTC by the relation TAI = UTC + dAT, where  dAT is the total algebraic sum of leap seconds.

The first leap second was introduced on June 30, 1972. The historical list of leap seconds can be found here.

The Global Positioning System (GPS) epoch is January 6, 1980 and is synchronized to UTC. GPS Time is NOT adjusted for leap seconds.

BEFORE THE 2012 LEAP SECOND: GPS-UTC IS 15 (GPS IS AHEAD OF UTC BY 15 SECONDS)
AFTER THE 2012 LEAP SECOND:  GPS-UTC WILL BE 16 (GPS WILL BE AHEAD OF UTC BY 16 SECONDS)

As of 1 January 2008, and until the leap second of June 30 2012
        TAI is ahead of UTC   by 34 seconds.
        TAI is ahead of GPS   by 19 seconds.
        GPS is ahead of UTC   by 15 seconds.

After June 2012,
        TAI is ahead of UTC   by 35 seconds.
        TAI is ahead of GPS   by 19 seconds.
        GPS is ahead of UTC   by 16 seconds.

I've been facinated by how computers keep time since I was taking a class on DEC Unix systems (longer ago than I care to mention) where it described how they had daemons that could keep an arbitrary number of computers in sync time-wise. It was pretty cool really, and predates NTP (Network Time Protocol). You would assign one system to be the Master. All other systems were Slaves to it. If for some reason the Master were to not be available for a certain interval, the Slaves would hold an 'election' amongst themselves and elect a new Master who would then take over those duties until/unless the original Master regained communication with the Slaves. That's almost exactly the terms used. At the time I thought it was funny.

That's probably more than anyone on this thread really wanted to know, but I'm bored, and this is something that interests me.

39 posted on 04/03/2014 8:59:58 PM PDT by zeugma (Is it evil of me to teach my bird to say "here kitty, kitty"?)
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To: zeugma
That's probably more than anyone on this thread really wanted to know, but I'm bored, and this is something that interests me.

It's certainly more than I knew! So thanks for the update. It's fun to read ... as long as, you know ... no quiz!

40 posted on 04/03/2014 9:09:14 PM PDT by dr_lew
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To: zeugma

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?


41 posted on 04/03/2014 10:44:41 PM PDT by zeestephen
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To: hoagy62
I think this is rather neat, myself. My wall clock gets the time signal from WWVB, which is now apparently tied in to the new NIST-F2. If that’s true, then I also have a very accurate clock in my own home.

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!

42 posted on 04/03/2014 11:06:28 PM PDT by Talisker (One who commands, must obey.)
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To: Beowulf9

“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.


43 posted on 04/03/2014 11:30:05 PM PDT by Nik Naym (It's not my fault... I have compulsive smartass disorder.)
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To: DManA
The definition of a second has nothing to do with the rotation of the Earth:

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.

44 posted on 04/03/2014 11:52:34 PM PDT by cynwoody
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To: Beowulf9
Anyone know if this is something an atomic clock can do, because otherwise we assumed it was my sister saying goodbye.?

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.

45 posted on 04/04/2014 12:23:13 AM PDT by cynwoody
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To: roadcat
Mother nature changes the time with each major earthquake

No, she does not.

46 posted on 04/04/2014 6:23:46 AM PDT by MosesKnows (Love many, trust few, and always paddle your own canoe.)
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To: zeestephen; Revolting cat!; GeronL

Do you still have to adjust it twice a year for Daylight Savings Time?


47 posted on 04/04/2014 7:57:39 AM PDT by a fool in paradise (The Texas judge's decision was to pave the way for same sex divorce for two Massachusetts women.)
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To: Revolting cat!

48 posted on 04/04/2014 7:59:35 AM PDT by a fool in paradise (The Texas judge's decision was to pave the way for same sex divorce for two Massachusetts women.)
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To: Scrambler Bob
Right 3 times a day?


49 posted on 04/04/2014 8:00:42 AM PDT by a fool in paradise (The Texas judge's decision was to pave the way for same sex divorce for two Massachusetts women.)
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To: roadcat

Does anybody really know what time it is?


50 posted on 04/04/2014 8:01:22 AM PDT by dfwgator
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