How to "see" earth is a sphere

Just look at this video...
#ws" class="bbc_link" target="_blank" rel="noopener noreferrer">Qu8k Rocket Launch Highlights - On-board GoPro HD at 22+ miles above earth

Ok that was not it... I made a drawing to easily explain how perspective works with the aperture of the camera lens and the shape of the earth.
Seeing by how round the earth looks in the video, one can asume its a pretty wide angle lens.

It could be even more than this, im not an expert at cameras, but that is not the point.

This is a representation of a big mass of earth surrounded by water on a flat surface and on a sphere (representing a continent) the red area is the are that is not visible by the camera, in a flat earth, in a high enough altitude it would be impossible to have earth on the horizon, you always see the ocean on the horizon (and the south pole, but almost imperceptible), because you can always see all of the earth.
On the other hand on a round earth it is very easy to see a "earth horizon" given the curvature.

If you watch the hole video, or others related, there are many points at where you can clearly see the earth going all the way to the horizon, you could also use Felix Baumgartner's videos to prove this, if at any point in any video of this kind, you see earth covering all the visible surface, now you know why that it.

We are aware how round-earthers say fields of view work. On a flat earth, the horizion is an illusion created by perspective. I would be interested if you could demonstrate a round-earth for us.

It is not about how you think it works or how I think it works. It is a known fact how it does work, and works the same with small objects as with big objects.



The horizon is just the line where the earth or the sea meets the sky in our field of view.

That field of view doesn't really depend on the shape of the earth, the example i gave takes perspective into account, the effect of perspective depends directly of the angle of view, not anything else, I would like to know how you think field of view works, if you could illustrated it could be better, "horizion is an illusion created by perspective" I don't know what you want to say with that.

It is not about how you think it works or how I think it works. It is a known fact how it does work, and works the same with small objects as with big objects.



The horizon is just the line where the earth or the sea meets the sky in our field of view.

That field of view doesn't really depend on the shape of the earth, the example i gave takes perspective into account, the effect of perspective depends directly of the angle of view, not anything else, I would like to know how you think field of view works, if you could illustrated it could be better, "horizion is an illusion created by perspective" I don't know what you want to say with that.

It's a common theme on this forum for people to claim something is easily provable and then be unable or otherwise unwilling to prove it.

Quote from: robertotrevor on November 10, 2012, 12:30:10 PM

It is not about how you think it works or how I think it works. It is a known fact how it does work, and works the same with small objects as with big objects.



The horizon is just the line where the earth or the sea meets the sky in our field of view.

That field of view doesn't really depend on the shape of the earth, the example i gave takes perspective into account, the effect of perspective depends directly of the angle of view, not anything else, I would like to know how you think field of view works, if you could illustrated it could be better, "horizion is an illusion created by perspective" I don't know what you want to say with that.

It's a common theme on this forum for people to claim something is easily provable and then be unable or otherwise unwilling to prove it.

Are you talking about me or pongo?

Because I just proved something, but according to pongo and apparently you, the perspective distortion doesn't work like architects and artists know it does, and im still waiting for any of you to explain me, not with words, but with a graphic, how you believe it does work.
But he hasn't answers yet and you just came to say i haven't proved anything? when in fact I did, but you haven't told me why i'm wrong, you only stated it.

If you were talking about pongo ignore that.

I was talking about this sentence in particular:

It is not about how you think it works or how I think it works. It is a known fact how it does work

Which you failed to back up

I was talking about this sentence in particular:

It is not about how you think it works or how I think it works. It is a known fact how it does work

Which you failed to back up

Ok, I thought the image i made was clear:
Light hit objects, it bounces and the light reaching the eye is projected as an inverse image which is later rearranged by the brain (or we would see things upside down). The angel of aperture drawn as black lines coming out of the eye (that thing in the center is an eye) depends on the lens curvature (in our vision i think is the cornea), as you can see the farther away the objects are, the smaller the projection, that is what is called "perspective". You can see how it works in the image i drew.

Now tell me how it does not work that way or why do you think my first statement is wrong.

Some shading would really help your diagram.

Not really, what is important in the diagram is the red and black lines, but it seems to me like none understated my point (or what i was talking about), i thought i didn't have to explain how perspective works but for the answers i got, i think i should have done that.

The perspective lines of objects closest to the horizon converge more rapidly than those distant from the eye-line. Using traditional art school perspective with a vanishing point an infinite distance away is ignoring the true nature of perspective.

What do you mean by closer to horizon, objects that are far away? I don't know what you mean by the "eye-line"
Also, i don't know why are you talking about "objects" far away, I'm talking about the whole earth, my point is, If the earth was flat, you could see the end of from anywhere with enough altitude to see over the mountains, if anything, the thing preventing us from seeing the end of it would be haze, not a matter of perspective, but that is not the case.
Also i think i would find easier to understand what you mean if you showed a graphic of what you mean.

I don't know what you mean by the "eye-line"

I'm so glad that you the expert are here to teach me, the novice, about perspective.

http://www.dummies.com/how-to/content/drawing-geometric-perspective.html


The problem with this standard art school perspective, however, is that perspective lines further from the horizon do not converge at the same rate as those closer to the horizon/eye line.

I'm just a fan of good diagrams.

I'm so glad that you the expert are here to teach me, the novice, about perspective.

http://www.dummies.com/how-to/content/drawing-geometric-perspective.html


The problem with this standard art school perspective, however, is that perspective lines further from the horizon do not converge at the same rate as those closer to the horizon/eye line.

Yea, because I called myself an expert, I would have known what you meant, if you said "eye level" which is the correct term i think you were referring to, in that link there is no "eye line" either.

Still, I'm not completely sure you understand my point as you are making emphasis on the vanishing point, (just in case, the second drawing I made is not Illustrating a vanishing point either, it just shows how light reflected from objects interacts with the eye) but of course lines do converge faster closer to the horizon using the graphic i made.

On the left equidistant lines on the floor, on the right lines getting closer as the reach the horizon.
I would accept you saying that's what prevent us from seeing the whole earth if I was using a picture or a video taken at eye level, with a horizon parallel to the floor, but im not, its a video from a rocked looking down, it makes the earth horizon (which in this case would not be the same as the eye level, or camera level) go up farther from where parallel lines converge, and in a flat earth the earth horizon would be even higher (farther from eye level where parallels converge) than in a round earth, where the horizon just stops when the curvature makes the earth go down.

Yea, because I called myself an expert, I would have known what you meant, if you said "eye level" which is the correct term i think you were referring to, in that link there is no "eye line" either.

http://bit.ly/SMYD2h

I'm pretty sure you're beyond civil discourse now (if you ever were at that point, judging by your tone), so I'll stop wasting my time.

Oh no, please come back, ill put a happy face to the end my sentences   
Please enlighten me with you knowledge.
Cheap Good way of getting out of the argument though.

But really if that is "beyond civil" I could have said you were beyond civil discourse when you sarcastically said this

I'm so glad that you the expert are here to teach me, the novice, about perspective.

I didn't know you were that sensitive, but it's ok, at least you tried.

i thought i didn't have to explain how perspective works but for the answers i got, i think i should have done that.

I would have known what you meant, if you said "eye level" which is the correct term

What people have been trying to tell you is that ocean (and land) beyond the closest land masses is effected by perspective, and further that art school perspective is not sufficient to the task. In the distance the expanse of earth is indiscernible due to the angular size. With more altitude one would eventually see more and more of the disc and it's true form -- eventually seeing those oceans (and later the rim-country) appear on the horizon. 

Your argument is nonsensical because your original drawing is not anywhere near to-scale. At the actual scale altitude involved, the angular size of the oceans and rim-country is imperceptible.


The diameter of the known world is 25,000 miles. The questions you should be asking yourself are: How far above the land mass (22 miles) is the observer if your diagram is to scale? At what point to the objects in the distance become too small to discern horizontally due to their angular size? Why would I expect to see/discern ocean (or rim-country) in that incredibly thin slice at the horizon?

Ski, the whole of standard perspective theory is based on angular size.  Angular size is easy to calculate - you just need to take distance and actual size into account.  It has nothing to do with the eye line.  In fact, objects converge on their vanshing point faster the bigger, or further away they are from it.



Notice how the top edge of this vehicle, while farther from the eye-line or camera-line than the bottom edges of the windows, is on a steeper angle.  The top edge of the vehicle, the bottom edge, and the horizontal edges of the windows will all converge on 1 vanishing point, and not several.  Different apparent distances from the horizon do not result in different vanishing points.  Different vanishing point result from different orientations.  If the vehicle were spun slightly, only then would the VP change.

Yea, because I called myself an expert, I would have known what you meant, if you said "eye level" which is the correct term i think you were referring to, in that link there is no "eye line" either.

Still, I'm not completely sure you understand my point as you are making emphasis on the vanishing point, (just in case, the second drawing I made is not Illustrating a vanishing point either, it just shows how light reflected from objects interacts with the eye) but of course lines do converge faster closer to the horizon using the graphic i made.
...
On the left equidistant lines on the floor, on the right lines getting closer as the reach the horizon.
I would accept you saying that's what prevent us from seeing the whole earth if I was using a picture or a video taken at eye level, with a horizon parallel to the floor, but im not, its a video from a rocked looking down, it makes the earth horizon (which in this case would not be the same as the eye level, or camera level) go up farther from where parallel lines converge, and in a flat earth the earth horizon would be even higher (farther from eye level where parallels converge) than in a round earth, where the horizon just stops when the curvature makes the earth go down.

The only problem here is that perspective, horizon, eye level and vanishing points are all subjects of drawing techniques, not of Physics!

You can argue with them all day long but in the end they will still show a drawing technique and spin it as a Physics demonstration of a flat Earth. And they can run circles around you all the time because drawing techniques are not an exact science, so there is a lot of leeway for all sorts of demonstrations.

The only problem here is that perspective, horizon, eye level and vanishing points are all subjects of drawing techniques, not of Physics!

Not drawing techniques - geometry.

Perspective, horizon, eye level, and vanishing points exist in real vision too.  You're right that it isn't really physics though.

What people have been trying to tell you is that ocean (and land) beyond the closest land masses is effected by perspective, and further that art school perspective is not sufficient to the task. In the distance the expanse of earth is indiscernible due to the angular size. With more altitude one would eventually see more and more of the disc and it's true form -- eventually seeing those oceans (and later the rim-country) appear on the horizon. 

Your argument is nonsensical because your original drawing is not anywhere near to-scale. At the actual scale altitude involved, the angular size of the oceans and rim-country is imperceptible.
The diameter of the known world is 25,000 miles. The questions you should be asking yourself are: How far above the land mass (22 miles) is the observer if your diagram is to scale? At what point to the objects in the distance become too small to discern horizontally due to their angular size? Why would I expect to see/discern ocean (or rim-country) in that incredibly thin slice at the horizon?

Now you are talking about scale. The perspective system i illustrated works fine, when something becomes indiscernible, due to distance, to the eye, it also becomes indiscernible in the drawing, which is what would have happened in the third drawings if i kept adding lines. But you are right, at that height sea would still be indiscernible in some directions.

The only problem here is that perspective, horizon, eye level and vanishing points are all subjects of drawing techniques, not of Physics!

You can argue with them all day long but in the end they will still show a drawing technique and spin it as a Physics demonstration of a flat Earth. And they can run circles around you all the time because drawing techniques are not an exact science, so there is a lot of leeway for all sorts of demonstrations.

This topic was never supposed to be about physics, unless you are going to tell me how the way photons travel over a few seconds or much less is irregular enough to distort the vision, based on physic laws, i don't see what physics has to do with this.
But I could still prove the earth is round based on perspective and range on view, just not with any video, as knowing things like the angle of view and direction the camera pointing would help make the calculations more precisely, knowing how they would look if the earth was flat and if it was round. But I don't see that happening.

This topic was never supposed to be about physics, unless you are going to tell me how the way photons travel over a few seconds or much less is irregular enough to distort the vision, based on physic laws, i don't see what physics has to do with this.
But I could still prove the earth is round based on perspective and range on view, just not with any video, as knowing things like the angle of view and direction the camera pointing would help make the calculations more precisely, knowing how they would look if the earth was flat and if it was round. But I don't see that happening.

If only every FE "theorist" agreed with you in the fact that this subject is not Physics but Geometry.

Rowbotham was the one who initiated this brain dead idea that perspective and vanishing points hide the boats that should be clearly seen if Earth was flat. Maybe at that time people were a lot more ignorant and were led to confusion just by talking a lot and using three syllable words, but we know better now.