[time-nuts] Measuring speed of light or reproducing a metre
Jim Lux
jimlux at earthlink.net
Mon Jun 24 21:56:37 UTC 2013
On 6/24/13 5:21 AM, Brian Alsop wrote:
> The time issue was effectively eliminated by the Michaelson-Morley
> interferometer. One used a monochromatic light and an array of mirrors
> which split the light in opposite directions around the track. The two
> beams were recombined and an interference pattern resulted. One counted
> the number interference fringes passing by while moving one mirror in
> one path.
>
> Knowing the number of fringes, wavelength of light and the mirror
> movement, one could compute c.
There are easier ways to measure wavelength of an EM wave (Young's
double slit experiment, for instance), or measuring the voltage along a
transmission line carrying a reflected wave.
BUT, then, an interferometer (or melted marshmallows in the microwave
oven) tells you the wavelength of the EM radiation. But you need to
know the frequency of that signal in order to calculate c from that
measurement.
and we're back to the "what can be done simply to measure time/frequency"
(I guess.. it's all really arbitrary.. a meter is so many wavelengths of
the light from a Krypton lamp)
>
> htt
More information about the Time-nuts_lists.febo.com
mailing list