# Sunset on globe earth versus flat earth

Discussion in 'Flat Earth' started by Amber Robot, May 24, 2017.

1. ### Amber RobotMember

I have seen claims by the proponents of the flat earth model that what looks like a sunset is actually due to perspective from the sun moving farther away in its "orbit" above the flat earth. This can be shown with simple trigonometry to be completely false; in fact, the trigonometry shows you that in the flat earth model, the sun never gets close to the horizon, and thus viewing a sunset at all proves the flat earth claim false.

I have read debunks of the claim, but they focus more on the angular size changes of the Sun that would result from the flat earth model, but I've been surprised that I've yet to find a presentation of the actual trigonometry that shows a flat Earth sunset never happens.

I submit the following scenario, with diagram and calculation: Imagine standing on the equator at solar noon on the day of the equinox. In both the globe earth and the flat earth models, the sun will be directly above you. However, this is where the similarity ends. Six hours later, on the globe earth, the sun will have descended to the horizon at a position due West. On the flat earth, the sun will have gone one quarter around its "orbit" and will be seen to be 19.5 degrees above the horizon in a northwest direction.

Even when the sun is 12 hours around its orbit, it won't be lower than about 14 degrees (atan(3000/12000)), though magically it will be unobservable and your surroundings will be dark.

It is disingenuous to present the setting sun as a "perspective effect" when it is so easy to show how high up in the sky the sun should be as a function of time. This perspective effect only works with objects with a very small ratio of height above the ground to distance from the viewer.

I submit this as sufficient to disprove the flat earth model presented above. The setting sun disproves the flat earth model.

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2. ### ChewSenior Member

Yep. I've asked several FEers why if the Sun appears to set while it is still XX° above the horizon how come nothing else appears to set when it is within XX° of the horizon like ships and distant skyscrapers and mountains. Replies to my question went from I don't understand perspective to the man who invented trigonometry was a Freemason.

3. ### Z.W. WolfSenior Member

The flat earth sunset is based on intuition not on analysis. Things appear lower in the sky, and closer to the horizon, the farther away they are. So far so good. But this is where they get into trouble. They intuitively assume that this process will continue indefinitely and as a simple additive process. In other words, if an object drops toward the horizon so much when it travels one mile away, it will be exactly twice that amount closer when it is two miles away. And three times closer when it is three miles away. And this will never stop. Therefore, an object will continue its downward path until it goes below the horizon.

Just putting this intuitive concept into words does it some damage, because putting it into words puts it into the realm of analytical thought. A purely intuitive thought is without language.

Your analytical argument will literally make no sense. The math will not be understood and will be rejected as nonsense which is refuted by simple observation.
See my argument here:https://www.metabunk.org/review-fla...ous-idea-christine-garwood.t7950/#post-205390

Last edited: May 24, 2017
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4. ### deirdreModeratorStaff Member

That's only because you don't understand FE perspective.

PS. without FE perspective, you don't need to show any trigonometry to see the sun never gets close to the horizon.

5. ### Z.W. WolfSenior Member

The arguments put forward by analytical people are often far too technical to help. The people who can understand them already do understand. The hard core FE believer is not the target audience, but as we've seen here on this MB there are people who are fence sitters and people who know there is something wrong with FE arguments but can't put into words exactly what.

For those people I've been trying to assemble a list of non-technical arguments which will clarify the problem. If they want to go onto the more technical arguments they can pursue an education in the matter. Most won't, but at least it's a start.

Here's my non-technical argument on this issue; with which I've gotten some measure of success:

Build a model of the FE disk world. If the earth is reckoned to be 20,000 miles in diameter and the sun is 3,000 miles above, simply cut out a cardboard disk 20 inches in diameter and place a marble 3 inches above the cardboard earth to represent the sun. Stretch a string from the marble to any spot on the model earth. The string is light from the sun. Is there anywhere on the model earth where you couldn't stretch the string in a straight line from the marble?

We can quibble about the size of the earth and how high the sun is, so we can go on to the next thought experiment. Put a BB any number of inches above a basketball court, and stretch the string from the BB to any part of the floor. Is there any part of the floor where you couldn't stretch the string in a straight line from the BB? No matter how big the floor, the floor doesn't interfere with the string. For the floor to interfere with the string, you'd have to drill a hole in the floor and go below the surface. Then the edge of the hole would interfere with, or touch, the string.

This is a simple and understandable demonstration. Any reasonable person should be able to clearly see that you can't hide an object from view on a flat surface no matter how far away it gets. There will always be a direct path. The only way you can get something to be hidden from your view is for that object to go behind an edge.

If they actually carried this experiment out physically on a basketball court they would quickly be able to see, with both some intuition and a basic level of analytical thought, that the angle of the string does not increase in a simple additive way when the distance between the BB and the spot on the floor is increased. The rate of change doesn't stay the same.

Last edited: May 24, 2017
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6. ### deirdreModeratorStaff Member

the only problem I see with that experiment is you say " The string is light from the sun", and FEers seem to think the sun is like a goose-neck desk lamp. meaning it only lights up a small area vs. flooding the room.

Visually, we could still SEE a goose-neck lamp 3,000 miles up from anywhere on a flat earth. Unless it diminishes in size as it moves away, but Mick's binocular thread proves the goose-neck lamp doesn't change in size.

7. ### Z.W. WolfSenior Member

That's another example of how using nothing but intuitive thought will get you into trouble. They're mixing two different issues together without realizing it.

If the sun were like a spotlight - the light only travels downward, not in all directions - we would see it disappear while still high above the horizon. The spotlight sun does not solve the angle above the horizon problem. Nor does atmospheric extinction.

Another thought experiment. Put a camera on the floor of a basketball court and move a gooseneck lamp father and farther away. At some point the rim of the lamp will interfere with the direct path of the light of the light bulb. The bulb will disappear. But you can still stretch a string from the head of the lamp to the camera. The spotlight sun would disappear when it was still above the horizon.

(And if there's any dust in the air above the basketball court to scatter the light, the camera would still see a beam of light. In the atmosphere there would always be something to scatter the light on the way down from the spotlight sun, so there would be perpetual twilight on some point of the horizon.)

The only way out is bendy light. If you go back to the scale model of the earth you would have to bend the string in a tight bow shape. Is that really the way light travels?

Edit: And thinking about it, even bendy light would still be scattered by the atmosphere, so there would still be the perpetual twilight problem. Except if the scattered light also bent, and bent in exactly the right way no matter what its new path was.

Last edited: May 24, 2017
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8. ### deirdreModeratorStaff Member

I forgot about the bendy light.

9. ### RorySenior Member

We don't know how light really works. There are many things we don't know. We're still figuring stuff out.

Agree?

10. ### Z.W. WolfSenior Member

If light can bend any which way you want it to on an ad hoc basis, then the whole, "Nobody has seen the curve" argument falls apart. It could bend to make a sphere look flat, or indeed as the hollow earthers affirm, a concave surface look convex.

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11. ### Amber RobotMember

You don't have to do the math to see from the model that the sun will be to the northwest 6 hours after being overhead, and not setting due west. The model just doesn't work.

12. ### omaehamoushindeiruNew Member

Is this sub-forum a place for refuting specific claims or another version of the "What to do about the Flat Earthers" discussion? Saying "x is based on intuition not on analysis" is a non-argument which can be applied to almost any FE claim.

13. ### deirdreModeratorStaff Member

you can probably lose the "almost".

metabunk debunks specific claims OF EVIDENCE. Unfortunately with FE, the vast majority of claims don't come with any evidence. So yea, this particular sub-forum is a lot more lax than other forums. There's just as much "explaining" the real science vs. actual debunking, because so few claims come with evidence attached.

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It's a general observation that illustrates the difficulty of debunking FE topics. It's normal for people to make errors in reasoning about all kinds of topics, but the Flat Earth topic is a bit above and beyond that type of thing.

We have here a demonstration of how under the conventional science of optics the sun would never seem to set on a Flat Earth. The FE answer to this that the sun sets due to perspective. It's hard to argue because it's such an intangible statement - as these statement are only hinting at what they are actually thinking.

Things get even more complex when they try to create models of what is going on. But even here there seems to be an intuition component. Things fall because they are heavier than air. The sun descends towards the horizon because of perspective, and so will continue to fall past the horizon. Rainbows are round because of the dome. There's very little in the way of actual attempts at science.

15. ### Z.W. WolfSenior Member

I'm certainly not going to pick a fight with you on this, and I'm grateful to the OP for taking the time to make a formal explanation, as my math is not only weak it's non-existent. I propose that there be differing levels of explanation; basic, intermediate and advanced. With the target audience once again being people who are willing to learn.

As a matter of fact I'd like to see a formal analysis of a very similar problem: The night sky and how it changes when the observer moves north and south. FE believers say that Polaris is at the top of the dome, just over the north pole, and its angle above the horizon when observed at different latitudes is entirely due to perspective once again. It's obvious that this won't work, but I'd like to see a formal explanation of the math involved in a close Polaris over a plane and an astronomically distant Polaris observed from the surface of a sphere earth.

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16. ### TrailblazerModeratorStaff Member

A good rebuttal to this "perspective" idea would be why it doesn't work in the other direction. A distant house gets "higher and higher" towards the horizon the further you travel away from it, so why doesn't it eventually rise up above the horizon?

17. ### Amber RobotMember

But "perspective" is a specific concept that can be quantified. And as my diagram shows, the quantification shows that perspective can't make it look like the sun is setting, given the parameters of that flat earth model.

So, the FE proponents want to take one scientific result and then extrapolate it outside of its applicability. That's either ignorance or malice. So, if they want to replace the word "perspective" with the word "magic", I'd be happier to entertain their proposition.

Sure, but there's your specific quantification, and their vague quantification.

For most people "perspective" refers to a collection a vague concepts - like things getting smaller as they get further away. It does not, in the average person's mind, refer to the visual size of a dimension perpendicular to the view vector being inversely proportional to the distance.

Unfortunately for a genuine zetetic you'd need to demonstrate that light does not bend significantly over large distance. Otherwise you are asking them to trust science.

19. ### Amber RobotMember

But they assume it doesn't bend over large distances when they say that the lack of curve of the horizon proves the flat earth. They can't eat their cake and have it too.

Just goes to show how intellectually dishonest they are.

"Dishonest" is a rather strong word to apply to a diverse group of people. Many of them are simply mistaken. Sure there's some motivated reasoning, there's also some deliberate ignoring of contradictions, and some trolling. But if you want to say people are being "dishonest" then you need to be a bit more specific.

21. ### Amber RobotMember

"Intellectually dishonest" as a compound term. What that means is that they are not applying their intellect honestly to all their mental endeavors. By presenting a quantifiable hypothesis and then either ignoring or even simply not calculating the observable consequences of that hypothesis they are being intellectually dishonest. They may not know they are being intellectually dishonest, but that doesn't mean they aren't. Hypocrisy is one of the most tenacious forms of intellectual dishonesty, but it isn't the only one. In fact, I'd say that if they simply stated their flat earth model worked because of "magic" they'd be exhibiting more honesty.

22. ### deirdreModeratorStaff Member

I think he means you need to show a specific example. For example look through Dubay's posts and present his claims and evidence, and show how he is being intellectually dishonest.

I think the majority of FEers don't even bother to see if all the pieces of the theory fit together. I actually doubt most modern FEers even know what all the pieces are. As far as the 'bendy light', I don't know how anyone (besides the few who made it up) can even comprehend it enough to know if it applies to one thing and not the other.

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23. ### Amber RobotMember

My OP addresses one. Presenting the setting sun as "perspective" when their model shows it won't get near the horizon and wouldn't even go in the right direction is being intellectually dishonest. He presents a model and then doesn't show how his model addresses real observations, because they would show his model doesn't work. So, is he being deliberately dishonest (i.e., he knows his model doesn't work, but he hopes to dupe the ignorant) or is he an ignorant dupe who has fallen for a sham model himself? I don't know, but to present the model without thinking through the observable consequences is an example of intellectual dishonesty while he simultaneously attacks the globe earth's observables. There are plenty more examples, but those would require threads of their own.

24. ### deirdreModeratorStaff Member

? I don't know what youre talking about. Mostly because your OP didn't link and quote an actual claim. I did let this slide because other threads in this particular forum have also not linked to a specific claim.

Their model isn't the evidence. I'm sure. Their evidence is the real world sun setting in the bendy light. no?

25. ### deirdreModeratorStaff Member

@Amber Robot think of it this way.. your 12 year old nephew, for some reason, absolutely believes Superman is real. He had a super vivid dream or saw (observation) a bird that looked like a man flying or whatever. The government only made the Superman movies (like NASA faking stuff) to cover up the fact of aliens on earth.
You are trying to disprove Superman to your nephew by trying to show that men can't fly.

The flat earth theory and parts like the bendy light, are a made up story to try to explain how their "I see no curvature" (observation) idea that they are absolutely convinced of can be.

Your nephew isn't being intellectually dishonest. imo.

26. ### Amber RobotMember

First of all, my nephew isn't an adult. He hasn't completed a formal education in which he'll be taught the thousands year history of mainstream science. He's not creating youtube videos claiming that thousands of years of mainstream science are wrong and he's the sole purveyor of truth against a global conspiracy. When he goes around spouting his theory and ignoring the consequences of his theory and ignoring obvious glaring holes in his theory that conflict with observables in the real universe then yes I'll start calling him intellectually dishonest.

And the Superman comparison isn't apt because that's trying to prove a negative on my part. But the flat earth theory isn't like that, it isn't something that one can never prove untrue because there just might be a flying man out there somewhere, it's something that makes specific quantifiable claims that are blatantly untrue.

27. ### deirdreModeratorStaff Member

hhhmmm... I was never taught the history of mainstream science in school. You seem to have some frustration issues with people who are not as intelligent/educated as you. You might want to consider just avoiding FEers altogether, lest your blood pressure goes into overdrive.

28. ### Amber RobotMember

You never learned F=ma in a high school physics class? Did you learn the earth wasn't flat? If you've taken a science course at all you have learned the results of thousands of years of mainstream science. Ok, I admit that I may have stated it incorrectly in that I said you'll learn the history. You may not learn the actual "history", but you'll learn the fruits of the labor of that history.

Claiming the earth is flat in the face of obvious evidence that disproves it is not like saying that there's a man who can fly and you have to prove there isn't, it's more like saying that Hillary Clinton is the President of the United States and offering up one piece of evidence (like she won the popular vote) while denying the whole structure that surrounds how the election works. Continuing to keep up the assertion despite its inaccuracy is intellectual dishonesty. Continuing to say Hillary Clinton won the popular vote, one piece of evidence that might suggest that she is President (like saying the horizon shows no curvature), doesn't make her the President.

29. ### deirdreModeratorStaff Member

But they have to see that evidence. They have to see micks thread on how to test that the Sun doesn't get smaller. They don't trust mainstream science.

I agree those who see the debunks and still keep posting their bunk links are intellectually dishonest.

I just don't personally think the majority bother to research the bunk ideas they see on YouTube. They are just intellectually lazy.

30. ### Amber RobotMember

That's why I focused on the sun setting. You don't need any tests, you just go outside and watch a sunset. It's about as unsubtle as I can think of an argument that disproves their model. You don't have to trust mainstream science, you just need to think about the consequences of your own claims. Maybe it won't prove the world a globe to them, but it destroys that particular flat earth model. If you're going to ignore the observable consequences of your own claims you might as well just say "magic".

Below is a photo I took from a Waikiki condo. This simply *cannot happen* if the Sun is 3000 miles up.

31. ### deirdreModeratorStaff Member

it's the Perspective Matrix dude. Wake up!

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32. ### EnricksMember

What is that supposed to be?

The "perspective matrix" is a weird interpretation of perspective which basically applies it twice. It imposes 2D perception (parallel lines seem to converge) on a 3D world, so parallel lines actually DO (kind of ) converge at a fixed distance (the horizon), then continue past it, hence "explaining" how the sun sets.

It makes absolutely no sense.

34. ### EnricksMember

I still don't get it. Is it a "not even wrong" type of explanation or can it be carefully analyzed and point out were it's wrong?

It makes absolutely no sense. It's wrong in that it does not reflect reality. The simplest observation of the sun staying the same size (instead of shrinking to a point) disproves it.

36. ### EnricksMember

Ah, so the "explanation" does not take into account the apparent size of the sun staying almost the same through the day and the sun actually setting like we see and not like a tiny point in the distance. I thought it was more interesting than this.

It is more interesting. That's just the most obvious thing that proves it false.

38. ### EnricksMember

"more interesting" in that I thought it would address those problems. But the double perspective thing is actually something I was yet to come across

39. ### ChewSenior Member

The flat earther's law of perspective somehow only applies to evidence that shows the Earth is a sphere (rising and setting celestial bodies, Sun and Moon never changing size, ships sailing over the horizon, buildings and mountains beyond the horizon, etc). Flat earthers seem to think that perspective is an actual physical object. They say perspective only makes it look like the Sun is setting but if that were true then the Sun should pop back up above the horizon and illuminate your surroundings when you turn your back to the Sun.

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I'm not really sure if the "perspective matrix" is a trolling joke, or a genuine attempt to explain what people are seeing. But some people probably believe it is correct.

What we have here is failure of communication. But it's a topic that's really hampered by its alienness to some people. They just don't really think about straight lines, parallel lines, triangles, point in space, etc.

I've spent more than half my life working with such things. I've been deeply familiar with the practical application of perspective since I wrote my first 3D rendering software as a teenager. I know how a picture is made in a camera, and I know that the "perspective matrix" is nonsense.

But most people just think of perspective as things getting smaller, and converging lines, like:

Then they might also remember seeing this:

They then perform a minor bit of mental gymnastics and get this:

Superficially this resembles the two vanishing points in the previous image. However they have taken something which is a 2D representation of looking down two streets at 90° and applied to the entire world from a side view - as if the lines actually DO converge.

It's interesting. I'd like to talk to someone who actually thinks this is real, and try to figure out what they are actually thinking.

Incidentally if you search for perspective+matrix without "flat earth", you get images of how perspective actually works, especially if you refine it with the word "frustum". It actually kind of looks like the opposite of the FE "perspective" explanation.