[rottingroom]

For the purposes of this demonstration, we will define a sunset as it is in the dictionary ("the time in the evening when the sun disappears") but with one important distinction that must fit with an important observation. That is, the manner in which the sun appears to disappear bottom first and become obscured by the horizon.

On a round Earth with a circumference of 24,901 miles, it is possible for a sunset to occur because we "turn" away from the sun. It is easy to see why this happens when we use this model.

On a flat Earth, it isn't so easy.

In this topic, I will perform some simple geometry/trigonometry to show you where the problems lie.

Now, I am aware that a common argument by flat earther's is to simply say that the atmosphere is not transparent and that we cannot see forever through the atmosphere. This is a non-sequitur given the definition above. If we were to dismiss the observation of the sun actually disappearing bottom first then this would be a valid explanation, but I don't think we should do that. The sun does not simply fade away. It is not important that the sun simply disappears, what matters is the manner in which it does so.

I have used the common sun height used by flat earthers of 3000 miles. That height is often cited as the correct height and flat earthers have been so kind to offer diagrams showing how they attained this number. Here is a common one that is thrown around:



For the distance from the observer to the sun, please observe the following image, taken from the flat earth wiki, which depicts the sun's trajectory about the flat earth:



In some detail, the FE Wiki also goes on to explain the following http://www.theflatearthsociety.org/tiki/tiki-index.php?page=Distance+to+the+Sun:

"On March 21-22 the sun is directly overhead at the equator and appears 45 degrees above the horizon at 45 degrees north and south latitude. As the angle of sun above the earth at the equator is 90 degrees while it is 45 degrees at 45 degrees north or south latitude, it follows that the angle at the sun between the vertical from the horizon and the line from the observers at 45 degrees north and south must also be 45 degrees. The result is two right angled triangles with legs of equal length. The distance between the equator and the points at 45 degrees north or south is approximately 3,000 miles. Ergo, the sun would be an equal distance above the equator. "

If the earth is flat then I would have to agree with the quote but despite the image of a flat earth above, which depicts the sun at about the equator, I will exaggerate in favor of FE and "pretend" that the sun follows a path around Antarctic ice ring. If this is the case, then the diameter of the flat earth should be about equal to the round earth circumference of 24,901 miles.

So, now let it be understood that we use the following numbers:

3000 miles for the height of the sun.
24,901 miles for the maximum possible distance between the observer and the sun's location above the earth. (Reminder: This is an extremely gratuitous exaggeration that should only help to support the FE'rs argument.)

With that in mind, consider the following diagram:



If you do not know how to do trigonometry with a scientific calculator then feel free to use this online right triangle calculator.

As you can see from the diagram, if the earth is flat then it is impossible for the sun to dip below the horizon as we all know it does. Therefore, it is safe to say that the earth cannot be flat because we experience sunsets.

[Yamato]

Nicely done, and I support your idea.
But take into account that it is possible to find objects in the universe that are invisible to unaided eyes, but become visible when you use any device with a bit more apperture than your eyes, such as small binoculars or very small telescopes.

But since FE acolytes doesn't seem to have this kind of knowledge, then your demonstration remains as true as the earth is round.

[rottingroom]

Nicely done, and I support your idea.
But take into account that it is possible to find objects in the universe that are invisible to unaided eyes, but become visible when you use any device with a bit more apperture than your eyes, such as small binoculars or very small telescopes.

But since FE acolytes doesn't seem to have this kind of knowledge, then your demonstration remains as true as the earth is round.

Yes but unlike the objects you are mentioning, the sun is very visible without binoculars before sunset. It would have to literally suddenly disappear for fet to be correct. What's important to take away from my post is that even though I used an obscenely large number (24,901 miles) for the maximum distance from the observer to the suns position over the earth, the sun still can't dip below 6°. A more realistic number would only make things worse for fe models.

[james_zombob]

I wonder why I see nothin from the flat earthers here...

[Rushy]

You can no more see the Sun from thousands of miles away in thick air than you can see five feet in front of you in a dense fog.

Nicely done, and I support your idea.
But take into account that it is possible to find objects in the universe that are invisible to unaided eyes, but become visible when you use any device with a bit more apperture than your eyes, such as small binoculars or very small telescopes.

But since FE acolytes doesn't seem to have this kind of knowledge, then your demonstration remains as true as the earth is round.

This assumes the only thing stopping you from noticing the light is that your eyes aren't sensitive enough. This is true in the case of some stars, however, in the case of not seeing the sun,  no light whatsoever penetrates the thick atmolayer. It doesn't matter if you have a 50ft aperture refractive telescope, you will see nothing.

[Gulliver]

You can no more see the Sun from thousands of miles away in thick air than you can see five feet in front of you in a dense fog.

Nicely done, and I support your idea.
But take into account that it is possible to find objects in the universe that are invisible to unaided eyes, but become visible when you use any device with a bit more apperture than your eyes, such as small binoculars or very small telescopes.

But since FE acolytes doesn't seem to have this kind of knowledge, then your demonstration remains as true as the earth is round.

This assumes the only thing stopping you from noticing the light is that your eyes aren't sensitive enough. This is true in the case of some stars, however, in the case of not seeing the sun,  no light whatsoever penetrates the thick atmolayer. It doesn't matter if you have a 50ft aperture refractive telescope, you will see nothing.

Cool. Please post your evidence that "no light whatsoever penetrates the thick atmolayer" as would account for the setting of the sun (and moon, and stars, and planets). I'd love to review it. Thanks in advance. (I'm particularly intrigued that "setting" occurs right at the astronomical horizon regardless of the source's intensity. That is so awesome.)

[Pete Svarrior]

In some detail, the FE Wiki also goes on to explain the following http://www.theflatearthsociety.org/tiki/tiki-index.php?page=Distance+to+the+Sun

While this isn't particularly significant here, I would like to generally advise against using Daniel's outdated version of the wiki (which stalled around 2010 or 2011 if memory serves me right). Please use the current version at http://wiki.tfes.org/ which includes content contributed in the years 2012-2014.

[Wulf]

You can no more see the Sun from thousands of miles away in thick air than you can see five feet in front of you in a dense fog.

Nicely done, and I support your idea.
But take into account that it is possible to find objects in the universe that are invisible to unaided eyes, but become visible when you use any device with a bit more apperture than your eyes, such as small binoculars or very small telescopes.

But since FE acolytes doesn't seem to have this kind of knowledge, then your demonstration remains as true as the earth is round.

This assumes the only thing stopping you from noticing the light is that your eyes aren't sensitive enough. This is true in the case of some stars, however, in the case of not seeing the sun,  no light whatsoever penetrates the thick atmolayer. It doesn't matter if you have a 50ft aperture refractive telescope, you will see nothing.

You are either avoiding or missing the point. The arguement here is not that we should be able to see through the atmosphere. We observes sunsets disappearing bottom first. If the atmosphere was blocking the sun in the manner you suggest than wouldn't the sun disappear gradually as the distance between you and the sun increased? Furthermore the math used above says that even if the sun was orbiting near the edge of the earth than it would never dip below 6 degrees, something we can clearly see with our eyes.

[Rushy]

No, the Sun would not disappear gradually.

[herewegoround]

We can see the sun drop to an angle of elevation of less than 0°. There doesn't seem to be universal agreement amongst flat Earth proponents about exactly how high the sun is above the Earth. Lets suppose the Earth is flat with the sun 3000 miles above it.

The distance across land to the point where the sun is directly overhead when it is at angle of elevation of x° would be given by 3000 ÷ tan x° on a flat Earth.

At an angle of elevation of 10° the distance is 17 000 miles. The furthest apart any two points on the Earth's surface can be is about 12 500 miles.

In this video I would say the centre of the sun is at an angle of elevation of about 5° at most.

If the sun was 3000 miles above a point on a flat Earth the sun would have to be above a point 34 000 miles away, assuming an angle of elevation of 5°.

There is also the problem of the path the sun follows in the sky, it is clearly not moving in a giant circle centred at the North pole.

[Wulf]

No, the Sun would not disappear gradually.

i don't know about you, but in a fog my hand gets gradually obscured as distance increases; could you elaborate? the more important observation, though, might be that the sun doesn't flatten out as the spotlight starts pointing away from you. The shape of the sun is consistent throughout the day so a flat sun spotlight isn't possible. I'd also like to know what flat-earthers think of sunspots and filiments, though more out of curiosity than anything else.

[Sentient Pizza]

In general a model is considered good/elegant when all of the ideas/assumptions build on one another and point toward the same set of conclusions. So I'd like to string some of the ideas in this thread together and then ask some questions.

As far as I understand it, the general FE position is this:
1 - the sun does not set (go below the horizon) or rise like in RE.
2 - The sun remains in the sky above the horizon at all times.
3 - We cant see it sometimes (at night) because of a combination of atmospheric conditions
4 - The atmospheric conditions (noted above) cause the sun to disappear from view quickly, not gradually like expected in a fogy condition.


Why can we ever see stars?
Why do they also go down to the horizon when we see them?
What is the mathematics basis for predicting sunset and sun rise accounting for these atmospheric conditions?
What other light based phenomena could we see the same kind of results/observations?

FE'ers please save this thread the kind of pedantic "we don't all agree on the model" kinds of responses. If you don't subscribe to the "atmospheric conditions are responsible for sun rises and sun sets" model my questions are not for you. Thanks