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  1. #1
    Markus Ludes's Avatar
    Markus Ludes Guest

    Default Why Human Eye is most sensitive in green ?????



    I hope to find here a expertise answere to this questions, asked to me
    by our neighbour who just started in astronomy.

    we all know that the human eyes are highest senstive at diffrent
    wavelenght on day or night time

    Now can somebody explain why the human eyes are most sensitive at about
    500 to 530 nm and not at 600 to 650 nm or 400 to 450 nanometer ?

    Is it just because God made it that way, or is there any biological or
    physical reason for that ?

    we asked several PHD Physics and Biological People and they all have
    been a bit confused because never somebody asked this question before
    and they even dont know the answere

    so is here somebody who can explain me the reason ?

    thanks

    Markus Ludes


    --
    Posted via Mailgate.ORG Server - http://www.Mailgate.ORG

  2. #2
    Shawn Grant's Avatar
    Shawn Grant Guest

    Default Why Human Eye is most sensitive in green ?????

    > so is here somebody who can explain me the reason ?

    Sure I can. It is because made it that way.



  3. #3
    Shawn Grant's Avatar
    Shawn Grant Guest

    Default Why Human Eye is most sensitive in green ?????

    > Sure I can. It is because made it that way.
    Oops! ^God



  4. #4
    Alan French's Avatar
    Alan French Guest

    Default Why Human Eye is most sensitive in green ?????


    "Markus Ludes" <apm_telescopes@web.de> wrote in message
    news:f3942c358e5e8c9e52487df949a51b3a.30545@mygate .mailgate.org...

    Markus,

    Evolution. The peak of our Sun's radiation is around 500 nm, so our eye
    evolved to make best use of the brightest available color of light reaching
    it. The same thing happened with plants and photosynthesis.

    Clear skies, Alan


  5. #5
    Martin Brown's Avatar
    Martin Brown Guest

    Default Why Human Eye is most sensitive in green ?????

    In message <f3942c358e5e8c9e52487df949a51b3a.30545@mygate.mai lgate.org>,
    Markus Ludes <apm_telescopes@web.de> writes

    There are some fairly obvious constraints, and some less so.

    At a purely chemical level the photosensitive pigments that evolution
    has landed us with happen to absorb mid green light best. Other species
    have a somewhat different wavelength range of optical vision.

    It happens that our sun's surface temperature has peak spectral emission
    around the region we call visible light. Had we evolved on a planet in
    orbit around a red dwarf with 3000K surface the result would probably be
    different.


    But any wavelength where the atmosphere is transparent and the photons
    carry enough energy to activate a molecular transition could in
    principle be used for vision. Pit vipers can see crudely into the
    infra-red and many insects have vision that extends out into the UV.
    Flowers have UV visible markings on them for the benefit of insects.

    For a good compound eye you also need a wavelength where eye lenses can
    be constructed from organic materials that are transparent. And where
    resolution is acceptable for the animal to see detail with an eye that
    fits into its head. We wouldn't get far with eyes sensitive to radio
    waves.

    Regards,
    --
    Martin Brown

  6. #6
    Chris L Peterson's Avatar
    Chris L Peterson Guest

    Default Why Human Eye is most sensitive in green ?????

    On Sun, 11 Jan 2004 13:47:32 +0000 (UTC), "Markus Ludes" <apm_telescopes@web.de>
    wrote:


    The most important factor in the responsivity of the eye is probably the solar
    spectrum. The Sun's peak wavelength at the surface of the Earth is very close to
    the peak sensitivity wavelength of the eye.

    No doubt there are secondary issues involved, such as details of the environment
    that the human eye (and its predecessors) evolved in, the chemistry of the
    retinal dyes, and others. But it seems very clear that the primary driving force
    in the evolution of the eye has been maximizing its sensitivity against the
    characteristics of the light source it uses.

    _________________________________________________

    Chris L Peterson
    Cloudbait Observatory
    http://www.cloudbait.com

  7. #7
    Shawn Grant's Avatar
    Shawn Grant Guest

    Default Why Human Eye is most sensitive in green ?????

    > Evolution. The peak of our Sun's radiation is around 500 nm, so our eye
    reaching

    There is no evolution. All things was created by God in 6 literal 24 hour
    days about 6,000 to 10,000 years ago.



  8. #8
    Chris L Peterson's Avatar
    Chris L Peterson Guest

    Default Why Human Eye is most sensitive in green ?????

    On Sun, 11 Jan 2004 14:35:54 GMT, "Alan French"
    <adfrenchremoveallthis@nycap.rr.com> wrote:


    There are at least three different pigment families involved with
    photosynthesis, with chlorophyll being the most common. Chlorophyll and
    carotenoid based photosynthesis use light at the red and blue ends of the
    spectrum, quite far from the peak solar output. However, because leaves reflect
    away the green light they can't use, the color of ambient light under forest
    canopies is shifted to the green, and this may have played a secondary role in
    the evolution of the peak sensitivity of our own eyes.

    _________________________________________________

    Chris L Peterson
    Cloudbait Observatory
    http://www.cloudbait.com

  9. #9
    Alan French's Avatar
    Alan French Guest

    Default Why Human Eye is most sensitive in green ?????

    "Chris L Peterson" <clp@alumni.caltech.edu> wrote in message
    news:ksr200ptriamujnu5ba337e3k24k5lghea@4ax.com...
    reaching
    reflect
    forest
    role in

    Chris,

    Thanks for the correction regarding photosynthesis. My biology suffers
    after all those years. I should have checked.

    Clear skies, Alan


  10. #10
    Mike Ruskai's Avatar
    Mike Ruskai Guest

    Default Why Human Eye is most sensitive in green ?????

    On Sun, 11 Jan 2004 13:47:32 +0000 (UTC), Markus Ludes wrote:


    I find it incredibly difficult to believe that several people with PhD's
    in physics or biology would be stumped by such a question.

    The sun's peak output radiation is around 500nm. Overall, the vast
    majority of the sun's radiation is in what we call the visible light
    spectrum. That is not a coincidence. It's no mystery why eyes on earth
    would evolve to be sensitive to the type of radiation that the sun emits
    the most of.


    --
    - Mike

    Remove 'spambegone.net' and reverse to send e-mail.



 

 
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