Soundly Proving the Curvature of the Earth

This thread on disproving flat-earthism with a natural experiment is interesting, for several reasons. @PdotdQ (and the other @physicists) , what is your thoughts about how a flat-earther might respond?

I note that this article is increasingly convincing because there isn’t a hint of condescension or frustration. There is just a careful explanation of evidence by Mick West. He is a really good example for us to follow in this regard.


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He uses chess pieces for the checkmate effect :joy:

Thankfully the internet has done the hard thinking for us from the Flat Earth Science and the Bible facebook group:

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Photoshopped! Trick camera angle. Those letters hanging in the air are clearly faked! Atmospheric distortion. It’s just a natural bulge over the back of the elephant.

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You forgot the perennial reply of flat earthers… “perspective”!!!

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Fascinating! In the right classroom context, it would be fun to take students through the “top ten undeniable proofs the earth is flat.” However, I think many would assume that the webpage is a Poe prank.

https://flatearthscienceandbible.com/2016/02/08/top-ten-undeniable-flat-earth-proofs/

It even implies that Captain Cook saw the alleged Antarctica ice wall blocking the edge of the flat earth! (That was before a vast military and naval presence prevented investigation.)

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I know how they will respond. This is a pretty famous picture in their circles. These two are the most often mentioned rebuttals:

  1. There are videos showing the same transmission lines with no curvature:
  2. There are videos showing that the curvature can be replicated in Flat Earth by throwing in atmospheric refractiong. See for example:https://www.youtube.com/watch?v=SDFw1Rw-WWY

The key issue with both claims is atmospheric refraction. In 1), during some strong weather conditions the atmospheric refraction can be strong enough to make the lines appear straight. Further, the strong weather conditions in 1) also made the atmosphere hazy that the sight distance is greatly reduced. In 2), the atmospheric refraction that they throw in is completely made up and does not match the conditions when/where the photograph was taken.

If one gives these answers, one must be ready to explain to them atmospheric refraction from a common ground (i.e. physics that they also agree with), and why it bends light the way it does (also why it bends oppositely during mirages). This is an example of needing to be better equipped than knowing high school physics to debate Flat Earthers. Most people who try to debate Flat Earthers only know high school level physics (often less physics than the Flat Earthers), so they cannot properly answer these objections, which entrench the Flat Earthers even more in their position.

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These, however, are explained in the thread. The didn’t use sufficient zoom or focus, right?

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Yes, typically the issue is not enough line of sight distance and poor focus, especially since these were taken during bad atmospheric conditions.

Here is the easy experiment. Send a fellow Flat Earther on an airplane from the US to the Far East. Call them now and again and ask each other if it sunny or dark. If one person says it is sunny with the Sun high overhead while the other says it is dark you have just disproven a flat earth.

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They have an explanation for this. The sun rotates in a circle that is parallel to the flatness of the earth. Not all the earth is night or day at the same time.

It doesn’t. There are timezones in Flat Earth models too. Their Sun is much smaller than our Sun and its light does not cover most of the Earth. If you say this in a Flat Earth debate, they will immediately dismiss you for being one of those people who try to disprove their model without actually knowing what their model is.

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And on this point they would be right!

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The title of the thread is “Soundly Proving the Curvature of the Earth”. I am aware of the ludicrous and unsound excuses the Flat Earthers have for denying these obvious pieces of evidence, but it is worth pointing out how soundly they have been disproven.

Given that their model can past your test, I don’t think your experiment has soundly disproven their model.

My point is that be careful when you debate; you have to attack their actual positions and not some strawmen that you constructed based on what you think their positions are. This is a huge pet peeve for the Flat Earth community, as these types of objections constitute the vast majority of the arguments unjustly leveled against them.

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It only shows how unsound their model needs to be in order to pass the test. If the Sun were as close as they claim then you would be able to measure a significant change in its diameter from points on the Earth just a few hundred miles away (which isn’t seen, and is another example of an experiment which soundly refutes their arguments). Not only that, but the Sun would have to be so small that fusion could not occur.

Again, I think you should read up on their models if you want to dismantle them. They have answers to all of these, some of them, admittedly, are quite clever. These are some of the most common objections to their models after all. I don’t want to spend my time defending them, so I won’t do it here.

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I have read up on some of them. Disproving them is actually kind of fun because you learn a bit about celestial mechanics.

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I do think it is fun, which is why I did it in the first place. However, please understand that your attitude is not helpful in a debate. You cannot come in with an arrogance that you have a surefire way to defeat their models, but then present an experiment that they have incorporated in their models for years. This just shows that you did not put effort to research their positions and give them their due process. This is a huge pet peeve for them, and will entrench them even more in their positions.

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I don’t think I would have the patience for it, so I will leave it in your very capable hands.

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A guy I went to school with recently became a flat-earther. I find this quite perplexing and I put some thought into how I could help him see the error of his ways. Where I live there is an extinct volcano on the beach, a small island out to sea, and an active volcano further out. I did some calculations showing where the horizon should be for a 40K km globe at various heights. Then I climbed the extinct volcano on the beach measuring my height and photographing how the horizon receded as I climbed from closer than the offshore island to well past it and nearly to the volcano. I even invited him to come and do the climb with me. Sadly this evidence was not sufficient to convince him. I realised if someone really really doesn’t want to believe in something then no evidence will be sufficient.

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