Quote:
Originally posted by: Tormod
No, I think Frank refers to something less related to human beins. The SI units are created by people
(ie, meters, grams, seconds). He is asking for true physical contants which are not "invented" by human
beings but rather discovered.
Frank, wouldn't the frequencies of the electromagnetic spectrum be constants? Waves could change,
but the frequencies themselves are always what they are.
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Yes, the SI constants are
created by humans using units (meters, grams, seconds). It is easy to
find a host of mathematical constants as they are invariably dimensionless, like Pi, a ratio.
Frequencies are not constants, the numeric value is dependent upon the definition of the time segment.
The physical length of a wavelength is invariable, but the numeric value we apply to it changes depending
upon what units we are using to describe a length. If I cut an iridium bar to the length of the wavelength
that results from the Larmor precession of neutral hydrogen, it would represent
1 wavelength. If I
want to describe that length in metric it would be 21.1061...+ cm long, or 8.3097...+ inches in English
units.
The frequency would be 1420.4 MHz whether I calculate the frequency using the speed of light in metric
or English units, because the length unit cancels. If I changed the duration of the time unit to something
different than the second the numeric value of frequency would change, but the wavelength represented
by the iridim bar will always be the same, "a constant".
Scientists
discovered the wavelength emission from neutral hydrogen, the length is constant. Why
isn't that wavelength used as a constant?
