The light is in our eyes...

Discussion in 'Physics & Math' started by Quantum Quack, May 21, 2017.

  1. Quantum Quack Life's a tease... Valued Senior Member

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    If it is as proposed by conventional theory that the light information has traveled from source and is actually in side our eyes then why do objects appear to be at a distance?

    The main purpose of this thread apart from general discussion is to discover what the terminology is used to describe the phenomena of a light source "appearing" at it's location when all we have is light info inside our eyes to deduce this from. (for the purposes of future research)
     
    Last edited: May 21, 2017
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  3. Q-reeus Valued Senior Member

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    Light i.e photons exist inside the eye only for the brief instant required to cross to and be annihilated by absorption at a cone or rod receptor and thereafter become a nerve impulse travelling to the brain. Stereoscopic sense obviously requires a multiple of photons coming from a finite solid angular field. Why not just use the web: https://en.wikipedia.org/wiki/Visual_system
    And ask for this thread to be moved probably best in Human Science or Biology & Genetics.
     
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  5. DaveC426913 Valued Senior Member

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    If you close on eye you cannot judge distance.

    Distance is an interpreted property in the brain, when we collate the information from our stereo vision.
     
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  7. Quantum Quack Life's a tease... Valued Senior Member

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    It is hoped that once the "Biology"is done with we can move onto the physics of photons and how they are being sensed/observed, experienced by the observer.

    An example question:
    Scenario:
    Single light source (light globe) in a darkened room. ( say around 10 feet away)
    One eye closed to avoid confusion.
    One observer

    Question:

    Would you say that the light of that source hits all photoreceptor cell (PRC) or cones on the observer's retina simultaneously? That is to say all PRC's are being effected simultaneously.

    If so, how is it the observer can still see the darkened background and the light as a single point in that room?
    Shouldn't the observer just see the light only (visual white out)?

    Image using an open doorway instead of a light globe.

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    Last edited: May 21, 2017
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  8. Q-reeus Valued Senior Member

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    Temporal delay between any receptors will be exceedingly small and only when sensing motion or flicker/flashing etc. is temporal change relevant at all. What matters in that example is the focal field generated at the back of the retina via the cornea and pupil acting as compound lens. The light bulb presents a small incoming angular field which is reflected in a correspondingly small field of PRC's stimulated. Which then transmits as a small bundle of nerve impulses that in whatever complex manner the brain works by, is interpreted finally as 'light bulb' in our consciousness. If the room is otherwise totally dark and the bulb is opaque i.e. frosted, and we don't know it is a light bulb 10ft away, there will be no visual cues to allow an accurate estimate of depth i.e. distance of source from observer. Just angular field and intensity.
    Open doorway case - well make it extreme - placed inside a completely opaque and uniformly illuminated integrating sphere used in photometry, then we have essentially uniform excitation of all PRC's and 'white out' will indeed be the perception. No sense of depth or direction - just light intensity.
    And I think that linked to article on vision probably does a far better overall job of putting it all together.
     
    Last edited: May 21, 2017
  9. Michael 345 Valued Senior Member

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    Proportion

    You do not "see" the surrounding blackness

    That is the area of the retina not being stimulated by the doorway light

    Question:
    Would you say that the light of that source hits all photoreceptor cell (PRC) or cones on the observer's retina simultaneously? That is to say all PRC's are being effected simultaneously.

    NO

    Light is FOCUSED into a portion of the retina

    Even if only one eye receives such information you might be able to guage distance since you are familiar with door size

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  10. Quantum Quack Life's a tease... Valued Senior Member

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    this is a bit I don't understand... care to explain it more...


    If I was to hold a small flat disc in front of the light globe the whole surface of the disc would be lit up. Why would I expect the retina to be any different to the disc?

    or...

    "The light globe lights up the wall behind the observer yet does not light up the whole retina? Why?
     
    Last edited: May 21, 2017
  11. Seattle Valued Senior Member

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    Because it's focused by the lens. I find it hard to believe that you don't understand this however.
     
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  12. Quantum Quack Life's a tease... Valued Senior Member

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    fair enough... ok so let's take a complete field of view, one with an infinite number of light sources. Each emitting individual photon waves.

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    with out concentrating on any part of the image above, I can see the whole picture including the led monitor it is displayed on and a good part of my room. How do we account for the all the light sources affecting the retina with out causing a "white out" (for lack of a better word)

    and further how do I see (observe) the vacant distance between me and what I am observing?
     
    Last edited: May 21, 2017
  13. Michael 345 Valued Senior Member

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    Again focus and

    the abundance of photoreceptor cells the two main types rods and cones of the retina

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  14. Seattle Valued Senior Member

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    Evolution.
     
  15. Quantum Quack Life's a tease... Valued Senior Member

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    does the eye also have "vacant space receptors?

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  16. Q-reeus Valued Senior Member

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    You've already got a few relevant answers but since I typed up a reply here it is:
    Because unlike that flat disc, your eye is similar to a camera lens. It focuses light. Exactly parallel incoming rays would in a healthy eye be focused to a very small area at the centre of retina. That would correspond to say viewing a star in the night sky - we are able to perceive it as a point source not a blurry blob.
    In the light bulb example, there is a finite angular spread of incoming rays and accordingly the eye will focus that to an extended patch at the retina. Hence there is finally a perception of a spatially extended source - more like watching the moon than say Venus.
    The eye is an incredibly well engineered piece of biological equipment! Unfortunately wear and tear tend to take a toll with age.

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  17. Quantum Quack Life's a tease... Valued Senior Member

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    There is no doubt at all that the human eye is utterly amazing in the way it works...
    The fact that we can see vacant space is staggering...and discern that there is more than one object in view with a separating distance.

    I guess I am trying to understand how multiple photon wave forms can enter the eye simultaneously and still maintain image integrity and how vacant space between objects both across ( perpendicular to line of sight) and towards the observer can still be observed.
     
  18. Michael 345 Valued Senior Member

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    There is the blind spot where the optic nerve exits the eye

    The brain may have a vacant space with no receptors

    Some of the post appear to come from such a region

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  19. Quantum Quack Life's a tease... Valued Senior Member

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    Scotoma
     
  20. Quantum Quack Life's a tease... Valued Senior Member

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    impressive!
     
  21. Quantum Quack Life's a tease... Valued Senior Member

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    so vacant space is observed using the Scotoma? You sure.....?

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  22. Q-reeus Valued Senior Member

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    Well the ability to perceive depth and so on is more than just optics alone. As was mentioned earlier this thread, close one eye and we are still able to perceive depth despite lacking binocular vision. Owing in part to that finite angular spread of incoming light that a single eye can then process to provide visual cues for the brain. But also importantly the outcome of a lengthy process of trial and error learning from toddler days. So info processing - pattern recognition etc. as a training process in the grey matter plays a huge role. Which gets it back to biology.

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  23. Michael 345 Valued Senior Member

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    Nooooo

    The blind spot is a scotoma BUT scotomas on other regions of the retina are not normal

    ***

    A scotoma (Greek σκότος/skótos, darkness; plural: scotomas or scotomata) is an area of partial alteration in the field of vision consisting of a partially diminished or entirely degenerated visual acuity that is surrounded by a field of normal – or relatively well-preserved – vision.

    Every normal mammal eye has a scotoma in its field of vision, usually termed its blind spot. This is a location with no photoreceptor cells, where the retinal ganglion cell axons that compose the optic nerve exit the retina

    https://en.m.wikipedia.org/wiki/Scotoma

    ***

    Really not sure what you mean by observing vacant space

    If you mean something like the black area around the lighted doorway

    Again you do not observe anything you do not receive light from

    Which includes space surrounding astronauts

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