/sci/ - Science & Math

Because that's how distance and light works.

This seems like it should be extremely easy to answer and I first thought you were an idiot, but I can't actually answer.

I am now curious as hell.

>>3742250
thats not a real answer and you know it-

It looks small because it only takes up a very small angle of our visual range.

When we look at something, the angle of our visual range can be modelled using trigonometry, as it can be considered with a triangle with our eyes as one corner, one side of the object we're looking at as another corner and the opposite side as a third corner, and the angle we're considering is the one in the corner where our eye is.

Here's a little example of how the triangle analogy can be used to describe what's going on. Say you were looking at an object 0.50 metres wide, and you are 5 metres away from the object. Then the triangle has an opposite side of 0.50 and an adjacent side of 5. To work out the angle, take tan^-1(0.5/5) to give an angle of 5.7 degrees.

Now you move back, to a distance of 20 metres. The object is still 0.50 metres wide, so the opposite side of the triangle is stll 0.50, but this time the adjacent side is now 20 metres. You again calculate the angle using the inverse tangent as before (tan^-1(0.5/20)) and this time you get and angle of 1.4 degrees, a smaller angle, and hence the object looks smaller.

Less photons reach your eyes

>>3742262

Well my first thought was that it is what happens when the light is projected on a curved plane aka the eye...

>>3742270
that answers how it works, but not why it works that way.

>>3742278

bump for answers

>>3742242

kinda hard to explain, but i get it. the back of your eye, where light reflects off of, is curved, so close stuff looks big, whereas far stuff looks small.

its like looking into one of those curved mirrors at the fair, but thats only on two dimensions...

its like looking at urself on a spoon.

A related but also interesting question is why we perceive objects to be further away as they get smaller.

>>3742430

i drew a picture to explain.the light(yellow) reflects off of the tree, and into our eye. our optic nerve(red), perceives this as the light that reflects off the back of our eye. and because the back of our eye is curved, the light reflects off at an angle. this is our field of vision(blue).

so the closer something is, the more of our field of vision it takes up, therefore, it looks bigger.

i hope this makes sense.

So does that mean if you had a flat photosensitive plate take an image, farther away objects on it wouldn't look smaller anymore? They would all suddenly appear to be their relative sizes.

Because that doesn't sound right to me. The amount of space each object would take up on the plate for one thing.

No yeah, curvature thing seems plenty wrong. How about just the further away from a source you are, the less of your field of vision it takes up.
Basically the same reason you can't see anything else if you put a your face right up to a wall, or a piece of paper is the same reason far away things look small.

>>3742448
But that only happens because of the first thing (far away things looking small, so a thing that has a known size getting smaller creates the illusion of getting further).
So only the first question needs answered.

>>3742491

yes, thats exactly what im saying.

i dont think photosensitive plates are flat.

although point taken.

>>3742487

answer lies somewhere between ---> >>3742491 and >>3742504

>>3742487
but a camera obscura works without a lense and a flat surface, and still produces pictures like our eyes.

>>3742625
oh i think i get it.
The hole acts as lense since it only allows photons to pass trough at this point and a specific angle...
Since all photons pass trough the same point you can calculate everything with trigonometry.

The curved surface isnt relevant its that all photons basically have to pass trough one point.

>>3742284
>that answers how it works, but not why it works that way.

So you're asking why the geometry of the universe is Euclidean? That's kind of a roundabout way of asking that question.

>>3742242
They are smaller relative to you because they are farther away from you. The objects are always the same size no matter what. Your reference frame just gives you a different answer. l2relativity

Strong autism ITT.

because your eye measures the angle that the light takes to reach your eyeball and the angle changes with distance

>>3742713
You're stupid and what you said is stupid. Now start pretending that you were trolling.

>>3742713
3/10 because I'm not sure if troll.

>>3742735
prove me wrong

>>3742692
i think the the question was: why can theangle of our visual range be modelled using trigonometry, and it was explained in this post:
>>3742676

>>3742242
>Why do objects that are far away look smaller.
The object-to-lens-distance changes, but the lens-to-retina-distance stays the same.

>>3742676
Your eye doesn't need to calculate trigonometry, it does it automatically.

Let me add a retina to your diagram and you should see.

Wow... a seemingly stupid question that cant be really answered. THIS IS SCIENCE!

it's called scale

>>3742771
wtf are you talking about?
the brain doesnt need to calculate angles or trigonometry.
See the blue line? its higher than the green one because the object is far away --->its perceived as smaller.

>>3742754
Oh shit, he really wasn't trolling.
> prove me wrong
Why? It's not the job of people who are competent to "prove wrong" people who are incompetent. It is the job of the incompetent to learn from the competent, or, to choose not to learn and remain ignorant. It would be a vicious cycle -- if every idiot who jumped in with some random theory "the universe is made of unicorns" had the right to be proven wrong, all of science would halt and every scientist would be completely consumed by falsifying ignorant theories. It's like negotiating with terrorists.

>>3742780
Has it really not been answered? The thread is already tl;dr for me...

The answer is called "projection." You can have an orthogonal projection (objects far away don't look smaller) or a perspective projection (objects far away do look smaller).

In an orthogonal projection, you draw parallel lines from the observer to the thing being observed. In a perspective projection, the lines converge at the observer. Our eyes just happen to use a perspective projection because the lines converge somewhere in the middle of the eyeball.

MSPaint illustration incoming...

>>3742829
thx i think we already figured that out-
So I have a new mission
>You can have an orthogonal projection (objects far away don't look smaller

Is there a way to build a camera taking pictures that way?

How do we know if a star is small and close or large and far away?

>>3742853
its not easy
http://www.talkorigins.org/faqs/astronomy/distance.html

Dudes, I think I have this.
Lets say you have a tree close to you and a tree 1 mile away.
They are both the same size through the magic of plotholes.
The tree 1 mile away will look smaller because as stated by >>3742713
Your eye uses the first tree for reference, judge the distance to the second as create the apparent size.

This can be proven with the moon illusion. When the moon sets below the horizon, it gets HUEEEEEG. This is because you consider the moon to be bigger than the trees on the horizon. Hold up a coin as a reference however, and the eye with auto-adjust, judge the distance and create a normal sized moon.

Ladies and gents, I've been high and rambling. g'night.

The further away an object is from you the smaller it becomes. Eventually if something gets to far away from you it disappears, this is why everything exists on the Earth, to be near you so that its existence can be assured.

>>3742864
too obvious dude.

>>3742849
Yes you fucktard it's called zoom

>>3742758
Here's an easy pinhole camera model.
d1 and d2 is the same object at different object-to-lens-distances. The lens-to-screen-distance (lens-to-retina-distance) stays the same. Therefore the projected size changes.

>>3742882
Then I invoke occams razor

>>3742879
How do you know a cinema screen is 50ft wide and far away from you rather than 50" wide and close to you?

>>3742915
Fucking context clues nigger.

>>3742829
MSPaint Image (over 9000 hours)

>>3742937
uhm no its mainly because you have 2 eyes and you focus the object with both so your brain takes the angle of your eyes and calculates how far the object is away from you.
However context clues will also help you

>>3742915

because our brains are wired to perceive depth, and our eyes accommodate to see objects sharp regardless of distance. They can only do that with a proper frame of reference and with the two of them, so with one eye shut, you will have a much harder time perceiving depth.

>>3742801
What the hell kind of rebuttal is that? How bad is your assburgers bro?

If anyone cares to tell me how the viewers reference frame doesn't play into to said viewer's perception, feel free.