So you think you know your way around the universe? Don't make me laugh, you don't know distance from doughnuts.
And hey, I found out today I don't either. The point came crashing home for me when for some reason in our philosophical foundations of Law class the teacher decided to explain what a meter is.
I mean, thats just, um... a hundred centimeters or so, right? Or ten decimeters, or a thousand millmeters. Yeah, and a thousand of those thousand gets us a kilometer... but the basic idea of a meter is really still self-referential.
So, let's go look it up in the books, shall we?
And so we see that an early definition is "the length of a pendulum with a period of one half-second".
Hm. So. Well, given that measuring a second is another major headache entirely (not to mention gravity varies at different points on the planet slightly), let's see if we can't quantify it some other way. How about: "one ten-millionth of the length of the Earth's meridian along a quadrant, that is the distance from the equator to the north pole".
Wait. How did they get that measurement in the first place if they couldn't quantify a meter to begin with? A really really REALLY long piece of string?
And...one ten-millionth? How random is that? Not to mention that it was figured out quite a while back that this measurement falls short about a fifth of a millimeter due to miscalculation of the flatness of the earth.
So about a century and a bit ago,in 1889, some bright soul decided to measure out an alloy block of platinum/iridium at the temperature where ice melts. But how did they measure it in the first place? And if you wanted to have your own measure would you have had to keep an alloy at freezing temperature and then let it get to the melting point so you could measure it?
Gah... so in the 1960's, someone really bright decided to measure distance as a function of wavelengths of light. And this is...um... because we know that light is measured in...nanometers. And this measurement of a meter came out to equal 1,650,763.73 wavelengths of the orange-red emission line in the electromagnetic spectrum of the krypton-86 atom in a vacuum.
Yeah, I'm sure we've all got something at home to duplicate this experiment.
And in 1983, we redefined distance as a function of light and time: "The metre is the length of the path travelled by light in vacuum during a time interval of 1/299 792 458 of a second".
But this takes us back a few hundred years where we were trying to figure out what a second was. Is... You know what I mean.
Yuck.
And under the International System of Units, the second is currently defined 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. This definition refers to a caesium atom at rest at a temperature of 0 K.
You know, I think I would have preferred it if someone... say, oh, a King or something, had just decided that the length of a meter was something like the length between his fingertip and the end of his thumb.
It's just as goddamn arbitrary and you avoid all those wasted years and billions of wasted effort.
Oh yeah, and you'd have to call it a "yard" and the Brits would get all insufferable about it because they'd be like "yeah, we thought of that first while you were swinging from pendulums in the stone age, you bloody colonists. See how much more sensible our system is? We can't keep all these milli- centi- deca- kilo- things straight. It's all Greek to us. Why can't you see how much easier it is to think it spans, cubits, fathoms, half-yards, fingers, nails and... I forget that last one... um... hardly ever use it... oh yes, INCHES."
And whoever thought up a decimal system anyway? It's unnatural. Twelve and Sixteen have way more factors and make for easier calculations anyday... blah-blah-God Bless the Queen - blah-blah... Fawlty Towers had it right... etc...etc...
Sorry.
I have an exam in 47 minutes and it's my fifth one in a week, with still one more to go. This was my brain taking a few minutes of holiday.
Thank you for your patience, we now return you to your regularly schedule reality in just a meter. Second. Whatever.
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