human vision is amazing

[lovebelow]

As far as I understand it, the only thing that allows man to observe the world around him is by way of this little invention called "the lens".

 

If it wasn't for this lens to focus photons coming from the same point on the retina than the eye would just get bombarded by a huge load of photons with no idea of where these came from and no means of building up a coherent picture. Am I the only one that finds this mind boggling that nature come up with this neat device that allows us to make sense of the world?

 

And if you follow through on this then we are damned lucky that light changes direction when passing from one medium to another. How would you else go about making a lens?

 

If my reasoning is flawed or you share my amazement, please respond.

[Nashyboyo]

I share your amazment. The retina is what interests me the most. The biochemical events that occur there are phenominal!

[insane_alien]

Meh compared to the rest of nature our eyes suck the big one. we can only see a small part of the spectrum and that in only three colours. we have a very limited range and a relatively narrow field of view. our depth perception is useless after about a mile and our retinas are on backwards.

 

The most amazing thing about our eyes to me is that the even work with all the stuff thats wrong with them.

[Bluenoise]

Meh compared to the rest of nature our eyes suck the big one. we can only see a small part of the spectrum and that in only three colours. we have a very limited range and a relatively narrow field of view. our depth perception is useless after about a mile and our retinas are on backwards.

 

The most amazing thing about our eyes to me is that the even work with all the stuff thats wrong with them.

 

Wow what did you sit on today?

 

Actually there is a very good reason why we can only see a small part of the spectrum.

[Norman Albers]

del

[Norman Albers]

Ultraviolet light is of higher energy than the visible light which was "canned" into carbon bonds. Thus it eats all organic materials left out in the sunlight. Could there be ultraviolet life forms? What molecular bonding regimes could give us some good sci. fi. here? . . . . . . . . . . . . . Try hangin out with a blind friend and talking for five minutes without using the word see! You're gonna feel stupid!

[sunspot]

The visable spectrum is at the right energy level for the needed biochemical changes associated with vision. IR is a little too weak and UV is a little too strong.

 

Once the light goes into the eyes, the optic nerves are like super high tech fiber optical cables that go into the brain. One of the important wiring points, on its journey to the back of the brain, is within the center of the brain, where it crosses itself and reverses the wires. The center of the brain is where memory is created, changing the visual signals into structural cerebral memory. This same wiring allows similar input signals to reinforce existing memory so we can become conscious of the visual stimulus while also allowing associations.

 

Added to this is the affect of the imagination. The optical wires terminate in the back of the brain. While the imagination is located in the front of the brain (more or less). This allows direct visual data to become superimposed with imagination based data. For example, this allows the scientist to see the real data while also using their imagination to analyze the visual data around theories in sort of in a see-saw fashion. The imagination can also directly superimpose onto the reality data to get a combined affect. This allows one to see pattens that overlay the direct sensory data. This is common at night in the woods, where shadows might look like animals. Or during cloud watching, where imaginary patterns appear in the clouds.

 

There is even one addtional piece to the puzzle. This has to do with sensory expectation created by knowledge. For example, if a pet rock is considered important by culture, the reality visual data of just a rock, can induce preprogrammed subjectivity making it more that it really it. This is part imagination, part direct visual, and part emotional/physical feedback.

[Bluenoise]

Ultraviolet light is of higher energy than the visible light which was "canned" into carbon bonds. Thus it eats all organic materials left out in the sunlight. Could there be ultraviolet life forms? What molecular bonding regimes could give us some good sci. fi. here? . . . . . . . . . . . . .

 

Umm none know so far. Carbon seems to be very special in the way it bonds. Silicon being the most simular compound doesn't even come close. It seems life will be carbon based if it's out there. Personally I see this as far more necessary than water. I could imagine life in an organic solvent, but not life without carbon. If there was life without carbon it'd most surley be very drastically different from life as we know it.

 

Oh yeah to continue my last post, the reason why we see the part of the spectrum that we do is that these wave lenghts correspond to those that can cause appropriate energy transitions in organic molecules that allow for vision.

Meaning that all energy of higher intensity (i.e. UV) breaks chemical bonds making it useless to us. And energy of lower intensity (i.e. IR) only causes slight kinetic vibrations. Everything inbetween (the visible spectrum) is able to cause electronic transitions in organic molecules that can be used to see.

 

Now some organisms can see slighly farther than us up and down the energy scale but this is rather limited.

[insane_alien]

i was meaning that there are animals that can see a good part of the IR and UV spectrums as well as our visible spectrum. i really did appear grumpy there didn't i. must be this cold.

[Norman Albers]

Meditate on feeling the infrared sphere around you. We feel it more than we usually realize. Sit in a room whose air is 70 degrees, and change the temperature of different segments of the the surfaces in the entire solid angle surrounding. You, THE BODY, clearly feel the BLACKBODY around you. I find the back of my hand to be sensitive. You may see me walking around seemingly waving at myself. . . . . . . . . . . . . . I like HYDROCARBON OCEAN BEINGS. Can we cook this up and make some money?

[insane_alien]

Meditate on feeling the infrared sphere around you. We feel it more than we usually realize. Sit in a room whose air is 70 degrees, and change the temperature of different segments of the the surfaces in the entire solid angle surrounding. You, THE BODY, clearly feel the BLACKBODY around you. I find the back of my hand to be sensitive. You may see me walking around seemingly waving at myself. . . . . . . . . . . . . . I like HYDROCARBON OCEAN BEINGS. Can we cook this up and make some money?

 

Ummm what drugs were you on when you wrote that? strong ones from the sound of it. it made some sort of sense until the last part after the ......

[Norman Albers]

Reefer to the entry by Bluenoise. . . . . . Eat salsa and JUST SAY NO TO COLDS.

[insane_alien]

Blue noise makes sense and i concur with his statements. yours how ever i cannot comprehend without twisting my brain into all sorts of 19 dimentional shapes.

[Cap'n Refsmmat]

As far as I understand it' date=' the only thing that allows man to observe the world around him is by way of this little invention called "the lens".

 

If it wasn't for this lens to focus photons coming from the same point on the retina than the eye would just get bombarded by a huge load of photons with no idea of where these came from and no means of building up a coherent picture. Am I the only one that finds this mind boggling that nature come up with this neat device that allows us to make sense of the world?

 

And if you follow through on this then we are damned lucky that light changes direction when passing from one medium to another. How would you else go about making a lens?

 

If my reasoning is flawed or you share my amazement, please respond.[/quote']

You could also use a pinhole to focus it, and it would work just as well.

[Norman Albers]

Sorry, we were connecting available frequencies and available chemistries for life forms, yah? . . . . . . . . . . . . Cap'n, did we then need to gather more? Your idea is so nice and simple that one would think this was the first evolutionary development: pinhole, retina, lens? Iris?

[the tree]

Well obviously the retina came before any focusing device. Then the cornea, and so forth.

[Sisyphus]

I don't expect there was an intermediate "pinhole" stage, since we don't really see that anywhere in nature, as far as I know. What we do see is a wide range of complexity in various "eyes," from basic photosensitive nerves that can only tell bright from dark up through several different configurations which are quite a bit more advanced than human eyes. The lens doesn't seem like a difficult evolutionary leap. Photoreceptors would naturally do better if protected by some transparent membrane, which would be directly shaped by evolutionary forces to better focus light. A pinhole configuration, on the other hand, would require an unlikely leap somewhere along the line, and so it isn't surprising that it never happened.

[Norman Albers]

Nice: I'll buy a round of beers on this. Are you saying the first simple eyes were sort of lensing mounds or something? I was hoping someone with the history would pop up here! The closed-down iris is a "pinhole", no? Was it last? Are 'the tree' and I crying in our beers for our theory? . . . . . . . I am intrigued about the comments of vision in other ranges. Infrared would be clearly useful at night in air. Isn't it strongly absorbed in water, so fish would not need it? How about ultraviolet, similarly examined. Is there only such a range that can be lensed?

[nanogrinder]

check out this illusion, stand about 12 feet back and they will switch places

[Norman Albers]

Weird. As soon as I take off my reading glasses the change starts happening about a third of the way. Levels of detail?

[StarBreaker]

Damnit, I dont have 12 feet to back up...Anyone have a link to a good site about the chemical bonds breaking etc. translating into vision. Sunspot perhaps?

[Norman Albers]

In Science News 2/11/6: "The patch of skin above a hawk's beak just looks orange-yellow to us, but to another hawk, it may broadcast UV sex appeal...this bit of skin, called the cere, strongly reflects light in the UV range.......Many bird species can see light in that range." (Scotland)

[DaveC426913]

As far as I understand it' date=' the only thing that allows man to observe the world around him is by way of this little invention called "the lens".

 

If it wasn't for this lens to focus photons coming from the same point on the retina than the eye would just get bombarded by a huge load of photons[/quote']

Actually, it's the cornea that does most of the focussing - the lens does comparatively little. The advantage of the lens is that it's variable.

 

And if you follow through on this then we are damned lucky that light changes direction when passing from one medium to another. How would you else go about making a lens?

Insect eyes have no lenses. They use a completely different principle for seeing. Don't underestimate the power of evolution.

[Cloud]

Eyes are pretty much the most important sensory organs in my opinion.

Without them you wouldn't really have access to the world.

 

Then again - they also are inefficient for the stress of today's competitive society. They weren't really 'designed' to cope with the education which we have to go through these days.

 

I mean - the reason we have eyes in the first place is to look for food (e.g. hunting)

 

Not looking at some book hours on end trying to figure out . . . what to write next.

 

I'm no biologist or anything but will the eyes ever adapt/evolve etc to cope with the stress we put on them by reading thick science books or spending too much time in front of the computer on internet forums???

 

I think this will take millions of years, right?

[[Tycho?]]

How do they not cope now? I can read books just fine, and I can read things on a computer screen just fine.