in reply to Re^7: I'm not a PhD but...
in thread How many colors does a rainbow have?

I'm sorry, but you aren't exactly making a lot of sense. While theoretically there are a lot of things that could happen for split seconds, depending on which receptors get hit, etc, the odds against them happening are incredibly high. And the odds against them continuing to happen long enough to get noticed are so high that that is effectively impossible.

To a very high degree of precision, a rainbow will cause specific pure frequencies to arrive at specific angles, with a calculable correlation between the angle and the spectrum that arrives. To a reasonable degree of precision, you will perceive a specific frequency of light as a specific colour. Most people will have the similar responses to specific frequencies of light. And there is simply no pure frequency of light that is perceived as pink.

This is pretty basic, and should be pretty simple. I have verified this in the past while looking at real rainbows, pictures of rainbows, and the output of prisms. Philosophical musings on the caprices of point sources, chance photons, and pure frequencies don't change it. Neither do howlers about why the output from cameras on various space missions needs massaging to produce natural looking photographs. (Giant hint, the various cameras used on space missions generally have frequency responses that aren't close to any of the major receptors in our eyes.)

As far as I am concerned this thread is over. Respond if you like, but I see no point in repeating myself.

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Re^9: I'm not a PhD but...
by BrowserUk (Patriarch) on Feb 05, 2009 at 11:16 UTC

    Since you won't take my word for it, and seem incapable of seeing that your schoolboy physics doesn't apply in the real world, trying reading the research by Raymond L. Lee, Jr. in his 1991 paper: “What are ‘all the colors of the rainbow’?”.

    I'll quote one paragraph from the intro that supports everything I've been saying above:

    Some 50 years ago, Humphreys pointedly noted that "the 'explanations' generally given of the rainbow [in textbooks] may well be said to explain beautifully that which does not occur, and to leave unexplained that which does.'

    Many nontextbook factors that affect the color and luminance of the natural rainbow still go largely unconsidered.

    These factors include:

    1. the angular divergence and coherence of sunlight,
    2. the optical path length of rain showers,
    3. the spectrum of raindrop sizes,
    4. aerosol scattering and absorption,
    5. aerodynamic distortion of raindrops, and
    6. illumination of the rainbow's background

    To do full justice to the natural rainbow, we must do much more than uncritically apply a rainbow theory to monodisperse, spherical raindrops that are illuminated by perfectly collimated light and seen against a black background.

    Examine what is said, not who speaks -- Silence betokens consent -- Love the truth but pardon error.
    "Science is about questioning the status quo. Questioning authority".
    In the absence of evidence, opinion is indistinguishable from prejudice.
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Re^9: I'm not a PhD but...
by BrowserUk (Patriarch) on Feb 05, 2009 at 02:06 UTC
    To a very high degree of precision, a rainbow will cause specific pure frequencies to arrive at specific angles,

    You surprise me Tilly. Cos that is utter bollocks.

    Get the equipment: PMOSFET image sensor; an optical collimator lens system; an optical refraction grid; and a spectrum analyser. Source your light from natural sources, and apply an H2O mist between the refraction grid and the detectors. Do the experients. Measure the frequencies. Then come back and claim that you know what you are talking about.

    And there is simply no pure frequency of light that is perceived as pink.

    True. But under natural lighting conditions, within any human measurable period, no pure frequencies of light reach the human eye. They are always a mixture of refracted, reflected and incident light from many origins and filtered through whatever molecules exist on their paths from source to eye.

    Update:Have you never seen pinks and purples in a sunset?

    Examine what is said, not who speaks -- Silence betokens consent -- Love the truth but pardon error.
    "Science is about questioning the status quo. Questioning authority".
    In the absence of evidence, opinion is indistinguishable from prejudice.
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