Why do objects look smaller just because the are further away?

Question

I asked this question some time agao and got good answers in terms of the way our eyes work, perspective, angles etc., etc.,...
I was told it was simple trigonometry and also asked "had I got a brain'?.
Well yes I have and the problem here seems to be the way I word my question.
Whilst I understand all your answers about angles etc., they seem to miss the point of my question....
Answers containing reference to things such as angles, field of view and perspective, seem to start at a point where you have already accepted that things appear smaller the further away they are and the human perception of them, but this is the very foundation of my queston, WHY do they appear smaller?
We have all been taught this fact since childhood, but go on to blindly accept it.
All I am asking is why?
My primary (and secondary) school teacher would have realy struggled with this one...
Can anyone offer any other insight?
Anyone really understand the question?

Answer 1

you should change your name to the wonderer or something
the thinker doesnt quite make it.

try to grab this pebble from my hand grashopper
not try to grab the moon ,it would fit in your hand

take it from there and work your way up.

Answer 2

Why does anything look the way we see it? How do we know something is really orange or red just because our eyes tell us it is.. We evolved eyes to find food and escape predators and find shelter etc etc. They work very well as we have obviously thrived.

The reason your brain interprets things as being smaller that are further away is simple. It helps to know how close that lion is thats stalking you out on the african savannah doesnt it? How high up that fruit is on the tree and wether youd need to climb to reach it. We wouldnt have survived this long if our brains and eyes hadnt been able to interpret the world around us.

Things may not look at all like they do to us when seeing from a spiders eyes, or even a cat or a dogs. Life is short and wasting time considering immutable things like this is a shame. Unless theres a problem with it, I would just accept thats how it works!

Answer 3

I think you are confusing the image of the object with the object itself. You have no direct connection to the object. You only have access to the light rays coming from the object. You do not perceive the object directly, you only perceive the light rays coming from the object. So the size you perceive the object to be visually is a combination of how the light comes to you, which is where all the geometry comes in, and the way your mind chooses to organize the information that your eyes provide, which nobody in the world understands fully.

And by the way, the sky is blue due to Rayleigh scattering.

(EDIT) I have been thinking about your question and have come to the conclusion that things DO NOT look smaller when they are farther away. They only subtend smaller angles when they are farther away. Smaller subtended angles can mean farther away, or smaller size, or a combination of the two. It is only you that have decided that smaller subtended angles mean only smaller size and not farther away, or rather that the farther interpretation is somehow less valid than the smaller interpretation of a smaller subtended angle; possibly because the term "smaller subtended angle" has the word "smaller" in it.

Answer 4

We have a field of view covering approximately 120 degrees (without moving your head). If you look at (for example) a 30cm ruler about 10cm away from your eye, the angle from one end of the ruler to your eye to the other end of the ruler is about 120 degrees. If you move away from the ruler by (say) 5 metres, then the same angle (from one end of the ruler to your eye to the other end of the ruler) is greatly reduced, to say 10 degrees. Your brain interprets this smaller angle as meaning either an object is small and near, or is large and a long way away. As the brain also controls the focusing muscles in the eye, it can determine how far away the item may be. The stereoscopic effect of having two eyes also confirms this, and the brain also uses a final method - experience - in its determination.

Answer 5

The light receptors called cones and rods, located in the retina of the eye, are responsible for our color vision and forms of objects

The sensitiveness is due to the chemical pigment they contain.

From the cones and rods signals pass farther into the system, where neurons along the visual path mix and match them until we can see the full world as we know it.

When an object is nearer to our eye, the light rays coming from the objects cover a large portion of the rods and cones in the retina.

If the same object is far away from our eye, the rays coming from the object fall only on a small portion of rods and cones of our eye. Therefore our brain interprets it as a small object.

A distant star which is many times bigger than sun appears as a point to our eye.

This is because, all the rays coming from the distant stars whose diameter is of the order of 10 ^6 kilo meters, after passing through our eye lens fall on very few rods and cones alone. Therefore our brain visualizes that as a small circle.

Even a slight motion of the eye ball, shifts the position of the image to different rods and cones and hence the star appear to twinkle, while there is no variation of brightness in the stars.

Answer 6

We see the light reflected from the object, this image is received on the retina of the eye, which acts as a screen. The eye behaves like a camera, the image is actually inverted on the retina, but our brain turns it back up the "right" way.

So, the size of the image on the retina will be smaller if the object is further away, and larger if it is closer. But really you need a drawing, to show it.

See Wikipaedia Pinhole Camera to see a sketch and explanation.

Answer 7

I have heard that there was once a tribe of rainforest dwelling people, who had never ventured out into open plains before. When they eventually did, the saw some bison on the horizon and thought they were ants as they looked so small.

So maybe it's all about perception and what we have learnt in our environment to survive. They never needed to know that things looked smaller further away as things were alwyas so close to them.

Answer 8

they look smaller because our eyes are made in the kind of fashion that they permit us to work out issues in attitude, so as that we may be able to tell form of ways some distance away issues are. If there became a tremendous monster 3 miles away, it would not be very useful to be watching its ft. so as that we may be able to work out the optimal means of our eyesight, products might want to look smaller or each little thing would look like a tremendous mess!

Answer 9

im guessing you are looking for a psychological answer

its because we use the apparent smallness of an object to 'deduce' that it is further away as a means of quickly assimilating a scene

we need such strategies since our eyes produce a 2D image of a 3D scene and binary vision is only effective over short distances because our eyes are close together

afterthought:
its a survival thing - if i see a tiger coming towards me and it looks big then i would perceive it as being closer - which makes sense since it is either small and close (hence dangerous) or big and further away (hence potentially more dangerous since its size makes it more likely to be able to eat me)

if the tiger looks small its either small and close (less dangerous as i might be able to fight it) or large and far away ( in which case i have time to run)

either way i need psychological strategies to speed up the way i perceive the situation since my life may depend on it

Answer 10

They dont appear smaller, the London Eye looks the size of the London Eye regardless of where it is viewed from, they simply appear further away. 9This may sound a bit of a silly answer but its not. )

Answer 11

I'm really struggling with this question to even consider you're capable of writing what you did.

Grow a few years, save money, and you may be able to fly Burt Rutan's next-generation "spaceship one" to the moon. You'll see it's a lot bigger once you get there, and lay this question to rest.

Thanks,
Buster