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Dalo

Sunny reflections

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I don't know if this subject belongs here, since it concerns less experiments than some observations I cannot explain using the laws of Optics. 

Only one sun reflected on the surface of a pond

Why is that? Shouldn't we see an infinite number of suns on the surface of the water?

Only one tree on the surface of the water

This is the same problem. We can see the single reflection of the tree. We can even go around it, and it will show us the same tree, seen from another perspective.

Can anybody explain how this is possible?

Edited by Dalo

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1 hour ago, Dalo said:

Why is that? Shouldn't we see an infinite number of suns on the surface of the water?

If the water is moving you ll see multiple reflections of the sun overlapping eachother into a (single) blurry reflection.

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1 hour ago, Strange said:

Nor sure why you think this is odd. You have looked in a mirror, I assume? You only see one of yourself.

See figure 6 on this page, for example: https://cnx.org/contents/YLRye4Ke@4/The-Law-of-Reflection

I have no problem with the laws of reflection, and I certainly understand them. As I understand the laws of optics.

What I do not understand is how they fit together.

 
The laws of optics explain how an infinite number of images can be formed of the same object. The laws of reflection explain how only one image can be formed.
 

34 minutes ago, Roamer said:

If the water is moving you ll see multiple reflections of the sun overlapping eachother into a (single) blurry reflection.

But you can only be blinded by the reflection if you stand at a certain angle of the reflection.

 

Edited by Dalo

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9 minutes ago, Dalo said:

The laws of optics explain how an infinite number of images can be formed of the same object. The laws of reflection explain how only one image can be formed.

I'm not sure what you mean by forming an infinite number of images of the object. When does this occur?

As I don't understand what it is you don't understand (:)) I don't think I can help ...

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Infinite reflections, finite number of eyes. Assuming a reflection off a flat surface, you are limited to seeing two.

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5 hours ago, Strange said:

I'm not sure what you mean by forming an infinite number of images of the object. When does this occur?

The way an image is formed through a lens, a pinhole, or our retina assumes that an infinite number of rays propagates from each point on the object. That is why an object can be seen from an infinite number of positions. That is also the explanation used in Optics to explain why images can be sharp or blurry. 

That is why I have difficulty with linking both groups of laws: the one depending on an infinite number of rays coming from each point, on one hand, and the fact that we are always seeing only one object on the other. The latter being explained by the laws of reflection mentioned in the link above.

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OK. That is exactly why I referred you to the diagram previously. Maybe you need to draw the diagram yourself to see why it works. 

Take the rays from various parts of the object (tree, sun, whatever) and reflect them from the surface. Most of those will, of course, miss your eye. The ones that do reach your eye can be traced back and will create a "virtual image" of the object, which is what you see. It may be probably easier to trace the rays in reverse: from your eye to the object.

You can ignore the "infinite" number of rays reflected because most of them don't each your eye (but some could reach someone else).

mirrorsfigure2.jpg?rev=5BBF

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1 hour ago, Strange said:

OK. That is exactly why I referred you to the diagram previously. Maybe you need to draw the diagram yourself to see why it works. 

Take the rays from various parts of the object (tree, sun, whatever) and reflect them from the surface. Most of those will, of course, miss your eye. The ones that do reach your eye can be traced back and will create a "virtual image" of the object, which is what you see. It may be probably easier to trace the rays in reverse: from your eye to the object.

You can ignore the "infinite" number of rays reflected because most of them don't each your eye (but some could reach someone else).

mirrorsfigure2.jpg?rev=5BBF

The other thing is our brain will filter out what it considers extraneous information. It actually sees two images and merges them into one, for starters.

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40 minutes ago, StringJunky said:

The other thing is our brain will filter out what it considers extraneous information. It actually sees two images and merges them into one, for starters.

Indeed. (See the concurrent thread on "four dimensions" for example.)

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3 hours ago, StringJunky said:

The other thing is our brain will filter out what it considers extraneous information. It actually sees two images and merges them into one, for starters.

This sounds like a homunculus-argument. How would the brain know what is extraneous information or not?

Instead of images, take simply shadows. Sundials are possible because all the sun rays go in one direction. Otherwise, we would have multiple shadows, just like when we have multiple lamps. 

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45 minutes ago, Dalo said:

This sounds like a homunculus-argument. How would the brain know what is extraneous information or not?

It learns what is important worth paying attention to and what isn't.

46 minutes ago, Dalo said:

Instead of images, take simply shadows. Sundials are possible because all the sun rays go in one direction.

Exactly. So why do you have a problem with reflection? Those rays would all be reflected by the same angle.

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1 minute ago, Strange said:

So why do you have a problem with reflection?

Again, I have no problems with reflection, nor with Optics in general. I am just wondering how to make them fit.

If light rays are propagated in all directions, why don't we get multiple shadows and multiple reflections?

 

3 minutes ago, Strange said:

It learns what is important worth paying attention to and what isn't.

https://en.wikipedia.org/wiki/Homunculus

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40 minutes ago, Dalo said:

This sounds like a homunculus-argument. How would the brain know what is extraneous information or not?

Instead of images, take simply shadows. Sundials are possible because all the sun rays go in one direction. Otherwise, we would have multiple shadows, just like when we have multiple lamps. 

It will make 'sense' of the data that comes in based on how it's intrinsically wired and what data it already holds in its memory. It will use the bits of incoming data that are useful to pursuing its objectives. What is 'useful' has been determined by evolutionary processes and experience. What we see is not a perfect mirror  of what's outside. 

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Binocular Fusion.

http://www.oxfordreference.com/view/10.1093/oi/authority.20110803095506642

You have two seperate cameras you are using with some overlap. Something like a Venn Diagram. More apparent if you cross your eyes.

The accepted theory is that the brain learns what is unchanging(nose) and filters that out for you. Not sure I totally agree, but brain definitely filters using some methodology.

I'd recommend thinking in terms of photons instead. There's a metric crap ton, going every which way, but they are not all reaching your retinas.

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2 hours ago, StringJunky said:

It will make 'sense' of the data that comes in based on how it's intrinsically wired and what data it already holds in its memory. It will use the bits of incoming data that are useful to pursuing its objectives. What is 'useful' has been determined by evolutionary processes and experience.

 

19 minutes ago, Endy0816 said:
21 minutes ago, Endy0816 said:

 

The accepted theory is that the brain learns what is unchanging(nose) and filters that out for you. Not sure I totally agree, but brain definitely filters using some methodology.

This is rather strange. It seems like you are basing Physics on Psychology/Physiology. Usually, it is the other way around, Physics being the ultimate science that explains everything.

 

22 minutes ago, Endy0816 said:

You have two seperate cameras you are using with some overlap

Why not simply use cameras and explain the images? You will still see only one reflection, and all shadows projected in the same direction, wouldn't you?

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When I first lost most of the vision in my left eye ( due to PDS glaucoma ), on bright days, I could still see the lane dividers while driving down the highway, and the image from my left eye did not match up with that of my right eye.
After an adjustment period my right eye has become dominant and my brain ignores the image from the left eye ( and all sorts of other things that it chooses to ignore ). Things are now a little less confusing, but unless I keep my eyes/head moving, depth perception is a big problem.


Are you familiar with ray tracing to put specular reflections on 3d digital objects?
They are extremely realistic because they are done backwards; from the viewer, to the object, to the light source.
Same as real life.
What you see, a reflection of light, is determined by the viewer ( eye ), not the object reflecting the light. 

Edited by MigL

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2 hours ago, Dalo said:

If light rays are propagated in all directions, why don't we get multiple shadows and multiple reflections?

Draw the diagram. Or write a ray tracing program. https://en.wikipedia.org/wiki/Ray_tracing_(graphics)

Maybe then it will make sense.

2 hours ago, Dalo said:

Your joking, right?

16 minutes ago, Dalo said:

This is rather strange. It seems like you are basing Physics on Psychology/Physiology. Usually, it is the other way around, Physics being the ultimate science that explains everything.

When it comes to sight, the brain plays a larger role than physics.

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20 minutes ago, Dalo said:

Why not simply use cameras and explain the images? You will still see only one reflection, and all shadows projected in the same direction, wouldn't you?

 

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Your eyes are essentially cameras.
But instead of an image on film, your retina produces a set of electrical impulses which are deciphered by your brain; sometimes even ignored, and sometimes extraneous information is added ( or did you really see everything doubled last time you were drunk ).

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1 minute ago, MigL said:

Your eyes are essentially cameras.
But instead of an image on film, your retina produces a set of electrical impulses which are deciphered by your brain; sometimes even ignored, and sometimes extraneous information is added ( or did you really see everything doubled last time you were drunk ).

Are you saying that even camera pictures should be considered as brain/mind images? That it does not make any difference whether we are registering an event through our naked eyes or through cameras?

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I don't think I said that at all.

A film camera produces an image on the film which cannot be ignored.

The eye produces analog electrical impulses which are deciphered by the brain, and can be ignored by a distracted brain, or added to by a hallucinating brain.

A digital camera produces digital data, which is interpreted by a computer, using Bayer filtering, for example, to produce color; use differing filters, get different colors.

See the differences, and similarities ?

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7 minutes ago, MigL said:

I don't think I said that at all.

A film camera produces an image on the film which cannot be ignored.

The eye produces analog electrical impulses which are deciphered by the brain, and can be ignored by a distracted brain, or added to by a hallucinating brain.

A digital camera produces digital data, which is interpreted by a computer, using Bayer filtering, for example, to produce color; use differing filters, get different colors.

See the differences, and similarities ?

What are you saying then?

We are talking about physics, whether all sun rays have the same direction, as seems to be suggested by the shadows pointing in the same direction. You are entering a discussion about differences and similarities between brain and cameras, which I suppose will help us understand why the sun rays behave this way, or at least why we have the (optical) illusion that they do?

Edited by Dalo

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14 minutes ago, Dalo said:

We are talking about physics, whether all sun rays have the same direction, as seems to be suggested by the shadows pointing in the same direction. You are entering a discussion about differences and similarities between brain and cameras, which I suppose will help us understand why the sun rays behave this way, or at least why we have the (optical) illusion that they do?

The discussion of the way sight works seems completely irrelevant to me. The fact that the rays from an object can be received (by an eye or camera) at any given point and a reflection seen is purely a matter of physics. Or even simple geometry. You can demonstrate it with a ruler and a protractor. I am beginning to wonder if you are really interested in the answer to the question.

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5 minutes ago, Strange said:

The discussion of the way sight works seems completely irrelevant to me. The fact that the rays from an object can be received (by an eye or camera) at any given point and a reflection seen is purely a matter of physics. Or even simple geometry. You can demonstrate it with a ruler and a protractor. I am beginning to wonder if you are really interested in the answer to the question.

But that is an answer I have in no way rejected. It is in fact quite obvious that there is only one reflection of an object on a reflecting surface, and that all shadows point in the same direction. So, when you are trying to prove it you are, as far as I am concerned, proving an evident empirical fact.

The question I am asking is how this obvious fact relates to the idea that light rays, in this case sun rays, are propagated in all directions?

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