Got a Second?

We’ve all heard it a million times: “This will just take a second.” Or “I’ll call you back in a second.” Or “give me a second, will you?” Usually we answer “yeah, sure” without thinking about it and then, depending on how truthful the second taker is being, start a slow burn process as that second turns into a minute or five minutes or, like, forEVer.

 

 This Is How Long a Second Is

(Approximately one flash per second; US-PD)

But how many of us ever take a second, literally, to think about how long a second is exactly. To find out, we have to break the second down into units, just as we break a minute into sixty seconds and an hour into sixty minutes. (Hmm, now I’m also wondering why we don’t, just to be consistent, have 60 hours in a day and 60 days in a month and 60 months in a year?) But which unit? We have milliseconds, microseconds, nanoseconds, picoseconds, all the way down to the yoctosecond.

Wait! What am I saying? We don’t have to break it down into anything. (Now you see why I avoided math and science as a career choice and chose something incredibly less lucrative.) All we have to do is provide a measurement of how long a second is. Simple, right. Back in the good old days, a second was defined as “the fraction 1/31,556,925.9747 of the tropical year for 1900 January 0 at 12 hours ephemeris time.” (In case you stumbled over the term “ephemeris time,” it’s “a modern relativistic coordinate time scale.” I’m sure that clears it up for you.)

Fortunately, modern science has taken over from that silly fraction of the tropical year 1900 idea. Now a second is measured as “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 caesium-133 atom.”

(Silence as several durations of billions of hyperfine transitions go by.)

You know what? I think I’m happy just to stare at the flashing dot above and say, yeah, that’s how long a second is.

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Visit Kim Pederson’s blog RatBlurt: Mostly Random Short-Attention-Span Musings