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Playing With Atomic Clocks At Home 167

Wired is running a profile of the Time Nuts, a small group of people who buy surplus precision time equipment — cesium clocks for example — on eBay and keep really accurate time, because they can. The article quotes Tom Van Baak, who has outfitted a time lab superior to those of many small countries: "If you have one clock... you are peaceful and have no worries. If you have two clocks... you start asking, 'What time is it, really?'"
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Playing With Atomic Clocks At Home

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  • Re:Clearly.... (Score:3, Insightful)

    by sm62704 ( 957197 ) on Tuesday December 11, 2007 @10:04AM (#21654835) Journal
    Funny yet insightful! How to mod, how to mod.

    Some people are way too anal. Jees, my ten dollar alarm clock is accurate enough for me, as are the cheap wall clocks, none of which ever differ by more than a minute.

    I have to set my clocks twice a year anyway. I don't have time to worry about what time it is.

    Next on slashdot: Obsessive Compulsive Disorder: Hallmark of the nerd? []

    -mcgrew []

  • Re:I don't get it. (Score:3, Insightful)

    by Alioth ( 221270 ) <no@spam> on Tuesday December 11, 2007 @10:12AM (#21654919) Journal
    It's a hobby. Some people like to ride, say, horses for a hobby. Not terribly useful now everyone has cars. What's the use? The use is that someone enjoys doing it. Like the horse rider, the time keeping hobbyist enjoys tinkering with highly accurate time pieces.

    If you have to question why people have hobbies you don't find interesting, you're amazingly lacking in imagination.
  • by sg3000 ( 87992 ) * <> on Tuesday December 11, 2007 @11:45AM (#21656099)
    > You do know that they proved this like 60 years ago right

    Yeah, but what made it cool was that the experiment could be repeated by a regular guy with surplus stuff from Ebay.

    "If you have one clock ... you are peaceful and have no worries," says Van Baak... "If you have two clocks ... you start asking, 'What time is it, really?'"

    Well, maybe not a regular guy, but you get the idea.
  • by leapsecond ( 748969 ) on Tuesday December 11, 2007 @06:29PM (#21663675)

    Good question about the 22 ns. Unlike the airplane experiments, because the van traveled slowly (60 mph max) and only for a few hours getting to and from the mountain, the relativistic effect due to velocity alone would be about 0.05 ns, or 50 picoseconds. Too small to worry about.

    The dominate effect for this experiment, since the van and clocks just sat still a mile-high for the weekend, is the gravitational relativistic effect. The GR time dilation rate is approximately gh/cc, which for an elevation gain of 1340 meters and a stay of 42 hours, comes to about 22 nanoseconds.

    More info on the trip is at []

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