The smoot is a nonstandard unit of length created as part of an MIT fraternity prank. It is named after Oliver R. Smoot, a fraternity pledge to Lambda Chi Alpha, who in October 1958 lay down repeatedly on the Harvard Bridge (between Boston & Cambridge, Mass) so that his fraternity brothers could use his height to measure the length of the bridge.
What does:
"a fraternity pledge to Lambda Chi Alpha"
mean? Is it even English?
Yank, actually.
Nice that Smoot went on to head ANSI, and then ISO.
The one I know is that one inch per second is one attoparsec per microfortnight (near enough).
I like the speed of light as measured to be *about* 1 foot per nanosecond .
And the "smidgen", with its sub-multiple, the "nano-smidgen".
I remember I was working in a chemistry lab in my year off before university in the early 80s. My lab supervisor was tweaking the proportions of a catalyst to find the amount that made a significant difference to a reaction rate, and he said "It just takes a smidgen" and then went on "To poison a pigeon". I must have looked mystified by this because he went on to explain the satirical songs of Tom Lehrer, whose music I came across the following year when one of my friends lent me his TL tape.
Then of course there's the alliterative furlong per fortnight, which is 1/8 mile in 14*24 hours, so 1 f/f is 37 * 10^-6 mph or 23 inches/hour or 16 *
10^-6 m/s. A garden snail travels at about 13 * 10^-6 m/s so roughly 1 f/f ;-)
- in fact, it is 0.9835710564304 ft/ns.
It has not been possible to measure the speed of light since 1986 or earlier; by/in 1986 it was defined in SI as 299 792 458 m/s precisely. The experiment can still be done, but, given that the second is well-defined and accurately-disseminated, the result is a calibration of whatever length standard was used in the work.
Be warned that from May 20th 2019, the definition of the kilogram will no longer be that it is the mass of a Pt-Ir cylinder cherished in Outer Paris. See in
Yeah like I said .
yes it has , it;s been in physics books long before then.
Yes so, but for most it was accurate enough even in the 18th century.
Yes I know I heard all about it. But it's not going to make much differnce to the majority of us is it. I also know the freezing point of water isn't 0C it's 0.01C IIRC.
But you can have stationary/ none moving water that is -4C
You misunderstand him. If the speed of light is precisely defined, i.e. invariable, and the second is precisely defined, also invariable, then the only remaining parameter not precisely defined is distance. Hence if you repeat the Michelson-Morley experiment, for example, you just end up measuring the distance between the apparatus and the distant mirror.
I think that you did not pay enough attention to my "since" above.
A Usenet response is commonly not aimed solely at the author of the preceding article.
Much effort, and time, has been put into achieving that, and having new standards which are independent of any artifacts.
It made little sense. are you saying the egyptians knew the speed of light, I've seen a ytube vid that claims they did. What's 1986 got to do with it, or are yuo saying the speed of light changed in 1986 ?
well I hpe that most realised that it's not going to change their life much. But a few (mostly women) might use it as evidence as to why the scales are wrong, again ;-)
Yeah time and money which for some might be better spent on other things.
He's saying that the speed of light was fixed in 1983 (not 1986) as an explicit constant, by the general conference on weights and measures (Conférence générale des poids et mesures, CGPM).
Quote "Improved experimental techniques that prior to 1983 would have measured the speed of light, no longer affect the known value of the speed of light in SI units, but instead allow a more precise realization of the metre by more accurately measuring the wavelength of Krypton-86 and other light sources"
No, I'm not saying that. But the Egyptians have always been on the fringe of Western scientific culture, so they would have known the speed of light soon after we did.
Which part of that do you want to be answered? s/or/and.
(1) Not a lot; I should have written "1983". The Web page "
(( Before that change, "However, the International Prototype Metre remained the standard until 1960, when the eleventh CGPM defined the metre in the new International System of Units (SI) as equal to 1 650 763.73 wavelengths of the orange-red emission line in the electromagnetic spectrum of the krypton-86 atom in a vacuum." ))
(2) At each of those changes, the speed of light changed, because the definition of speed incorporated the definition of the metre, which changed by an unknown amount as near zero as could be managed on the available information. It is possible, in principle, to measure, with greater precision than available in 1983, the wavelength of that line in terms of the current metre and/or the frequency in terms of the current second, and that would yield the value of the change in the speed of light.
Which 'Egyptians' are you talking about? The time of Tutankhamen? The pyramid builders? Cleopatra and the Greeks? Nasser? The Muslim Brotherhood?
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