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Atomic Clock Turns 50
karvind writes "BBC has an interesting story on the 50th birthday of atomic clocks. The first accurate caesium atomic clock was developed at the NPL in 1955 by Dr Louis Essen. And after 5 decades In September the US National Institute of Standards and Technology (NIST) used computer chip fabrication techniques to make a small atomic clock. The final development should see a battery-operated system about the size of a sugar lump. NIST also has a page on history of atomic clocks"
It's a good thing we had atomic clocks so we could be sure it was really 50 years!
Lump of sugar has to be the oddest comparison ever...
There are exactly 42,935,718 letter sized sheets in a square mile.
I used to be obsessed with accurate clocks, still am for my servers, but after awhile its all relative anyway ;)
The more you know, the less you understand.
The atomic clock turned 49.9999999999999999999999 today!
;)
Congratulations
liqbase
It seems that more and more of everything is sync'd with this. My clock radio at home auto-updates, clock on the wall, the cellphones, my Linux and Mac PC's and cable box.
Only thing left are the clocks with a single AA battery on the wall, and at some point they are going to use the pervasive WWVB time signal that is broadcast from Colorado and operated by the National Institute of Standards and Technology
This technology has really come a long way and is deeply embedded within our lives. Especially if you consider that before the atomic clock, time varied considerably between different locales.
Newsfollow.com
and we still don't have time travel. What a shame.
That article is not precise! The atomic clock is 50.00000100121412235901293409234 years old as I'm writing this.
Four scientists, as they flip the switch on their new invention ...
... ...
#1: Gee, Ed, it looks like it works
#2: Bob, you're right! It's counting! We did it!
#1: It seems to be right on, let's fire up the chronotaph
#3: Already there, Bob, I have a solid register, five-nines. I started the paper before you hit the button.
#1: Good thinking, Stan. This is one for the record books!
#2: This is a clock for your ass, Ed! I guess we should set it now.
#4: Okay guys (looks at watch) what have you got? I'm showing a quarter past two.
There really is no market for atomic clocks. At best you will get devices that sync themselves to an atomic clock, that's located far away. Even people that do have pretty accurate clocks are always late. I find that in general, most people are late, and don't really worry too much about time in the first place. Really gets on my nerves, as i'm always on time, and always have to wait for someone.
Anthropic principle: We see the universe the way it is because if it were different we would not be here to see it.
because without NTP, we might as well be using sundials.
This is a question that must get asked a lot, and I wasn't able to find an answer (casually searching) on the gov website.
How did they figure out how to set the clock initially? Thanks.
Anyone see that article a couple of weeks ago in New Scientist about Strontium atoms held in standing waves generated by 6 lasers? Mental. A 50 time more accurate (or something).
In Latin, the AE is pronouned like an "ai" dipthong and c's are always hard consonants. So Caesar would be pronounced like "Kaiser" and by analogy Caesium would be pronounced "Kaisium."
After all, I am strangely colored.
...the worlds first atomic wristwatch.
Uh huh, that's what it wants us to think....
"This food is problematic."
"I believe time travels slower at the equator than at the polls."
I don't know about that. When I was standing in line at the polls back in November, time seemed to drag on. Now, afterwards, it's dragging on even longer while we here in Washington State are still wondering who our governor is.
What's that? You meant poles? My mistake.
Give me my freedom, and I'll take care of my own security, thank you.
No, because he's essentially correct.
In VoIP protocols, a timestamp *is* placed in every packet along with a sequence number. The timestamp is used to place the incoming audio and video packets in the correct order with regard to time. The sequence number is used to detect packet loss. So basically, sequence numbers don't help you with jitter. The timestamp is use to actually calculate the amount of jitter, so it's rather important for it to be as accurate as possible.
Show me on the doll where his noodly appendage touched you.
The definition of the second is now based on the physical quantity that atomic clocks measure, so the clocks are, when functioning properly, correct by definition. They can therefore just look at how much agreement a bunch of clocks have with each other. That is, they don't have to worry about the issue of all of the clocks being systematically fast or slow, like if they were mechanical watches which could all be consistant, but all tick at a rate different from a second, because the second is defined such that this is not the case.
The Big International Scientific Conference that got together to define a new time scale to replace GMT had no difficulty coming up with the name "Coordinated Universal Time", but deadlocked when it came time to decide between the English acronym (CUT) or the French one (TUC). So they decided to use the symbol UTC, which doesn't stand for anything.
Leap seconds are used to keep UTC in sync with the Earth's rotation. Since the Earth's rotation is steadily slowing down, UTC would drift away from any sensible time if it wasn't adjusted every now and then. So they add the occasional extra second to keep them in sync.
GPS time runs at the same rate as UTC, but has no leap seconds, and is currently 13 seconds different. People who navigate by the stars use UT1. Then there is the Terrestrial Dynamical Time that astronomers use, which is another matter entirely.
...laura