| Chronology | Current Month | Current Thread | Current Date |
| [Year List] [Month List (current year)] | [Date Index] [Thread Index] | [Thread Prev] [Thread Next] | [Date Prev] [Date Next] |
>Hugh Haskell wrote:(twinkling)
>>
>> Interesting. And if it should happen that the reflector happened to
>> be in the center of the face of the moon directed toward us (I don't
>> know if this ever happens for the location of Tranquility base),
>> would we be able to see a reflection of the Poisson spot on the moon,
>> due to the constructive interference of the diffraction of the sun's
>> rays around the earth?
>
>Aren't the sun's rays incoherent? Try to create diffraction or
>interference patterns using pinholes or slits with a beam of sunlight
>as the direct illuminant. I'll bet you find that this doesn't work
>nearly as well as it does with the laser in your lab as the light
>source.
>
>Have fun! :-)
>
>--MB
Are you sure? Thomas young didn't have a coherent source when he
first showed the effect in 1825 or thereabouts. And we can do an
awful lot of diffraction effects with an incandescent light at a
source. In fact if sunlight isn't coherent, then starlight isn't
either and we get spectra of stars all the time.