baudrunner's space: More insight on sight
"Philosophy to Science - Quark to Cosmos. Musings on the Fundamental Nature of reality"

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Monday, January 21, 2008

More insight on sight

Some evolutionists make a claim against creation because they maintain that the organisation of the photo receptors and neural apparatus of our retinas is less than perfect. In order for light to reach the photo receptors it must first pass through a network of neural fibres. They say that a perfectly designed eye would have the inverse arrangement, with light waves striking a layer of photo receptors which are then translated into the information compatible with transmission through the optic nerve to the occipital lobe. The "inverted" arrangement is typical among the vertebrates and in the invertebrates only occurs in some mollusks and spiders. In effect, our photo receptors are wired in reverse, with the nerves gathering into a bundle which passes through the opening of the optic nerve, from the outside in.

structure of the retina

It turns out that what we have is actually the ideal arrangement for the very active metabolism of the ten layers which make up the retina. Studies showed that thermal damage related to light intensity occurred more readily in the retinas of dead animals than in the retinas of live animals. There is a very active heat sinking process which dissipates the thermal product produced by the combination of light stimulation and neural processing. In fact, this activity markedly increases with an increase in the incident rays striking the retina. The conclusion was that the arrangement of the retinal layers protects against thermal and erosion damage. Animals who have a "verted" arrangement generally live in dark environments and/or have a short lifespan.

The short and long of photons

Scientists are nowadays more inclined to refer to photon wavelengths than to light frequency. Photons are said to have a wavelength of so many meters or fractions thereof. The best example of this is seen in the interaction of photons with silicon in a CCD, or charge coupled device, in which the term spectral sensitivity refers to the absorption of photon energy in the potential energy well of the device. A paper on the subject will state that photons of wavelengths between 400 and 700 nanometers have the highest probability of generating an electron within the charge well. One would think that one might just as easily correctly state that light with a frequency of 750 to 430 Gigahertz is most effective in electron generation. However, scientists like accuracy and precision and are using the photon to help them establish these. Long live the photon after all! The equation relating wavelength to frequency, where frequency is equal to the velocity of light divided by the wavelength, is not always completely correct because waves of different wavelength can have the same frequency. What we are actually witnessing in light of this fact and others is a paradigm shift of sorts. While scientists are actually conducting experiments to "force photons" to exhibit particle behaviour, the jury is slowly but surely moving in on accepting the true nature of the photon. Eventually, they will agree that the speed of light is not truly constant.

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