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Topics - dephelis

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ok, than I have one question for u:

Why your shadow always remains on the groung till sundown?
If earth is round ball, your shadow must lift from the ground??

Because we're not tall enough for that effect to manifest clearly, mountains however ...

I face-palmed when I saw Scepti's description of how an eye works in this thread:

Here is a diagram of the human eye:

Let's work through his post to highlight where he is wrong and maybe help prevent someone else making the same mistake.
Think about the shape of your eye and think about how it views things. Your eye is concave. It's not a flat eye.
The light to your eye is going to differ over distance.

The shape of the eye has no bearing on the distance the light has travelled. It passively collects whatever light is available to it.

Stand on the beach and look out to sea. You may not be conscious of this but you can see the beach even though you're looking at a ship out to sea. Why?
Because your eye is concave. It views from all angles.

While the retina can be described as a concave surface, light is actually collected and focused by the cornea and the lens at the front of the eye. The outward (light source facing surfaces) of these two parts of the eye are both convex. The shape of the cornea is especially responsible for giving us the 170 field of view.

So if you're looking directly ahead the ight is hitting to top of your concave pupil and less so at the bottom of anything you are viewing, especially the further away it gets.

The pupil is not concave, in fact it is not anything at all. The pupil is the hole in the centre of the iris.

So thinking on that, your eye loses the hull of a ship because the bottom is only taking the light in from the reflection so far out. Basically you drop into the sea which becomes your horizon line.
It doesn't change at the sides because your eyes are still wide angled, taking in the light either side. The top part of your concave eye, catches the top of the ship/mast because it still reflects the light.

No the light gathers all light available to it. Eyes do not take in more light on the sides than any other direction.

If you notice with your pupil, it acts like a telescope as well. It widens to take in as much light as possible when the light becomes dull and when it's bright, it shrinks to focus.

Wholly incorrect. The pupil, or rather the iris, contracts or expands to allow more or less light in thereby adjusting exposure (equivalent of a camera's aperture stop), this has no effect on focus whatsoever.

Focus, in the eye, is provided predominantly by the cornea (around 70%) and refined by contraction or expansion of the lens independently of the iris.

Your eyes are just shit telescopes.

This is true.

The Lounge / Happy New Year
« on: December 31, 2014, 05:39:19 PM »
Happy New Year to one and all, even Scepti and AusGeoff. Jroa is still terrible though.  ;D

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