# How can one prove that the earth is a sphere (or close to it)? **URL:** \ **Category:** Factual Questions\ **Created:** [October 15, 2018, 11:50am UTC](https://boards.straightdope.com/t/how-can-one-prove-that-the-earth-is-a-sphere-or-close-to-it/822973 "2018-10-15T11:50:12Z")\ **Posts on this page:** 20\ **Page:** 5
**Author:** ![eschereal](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/eschereal/32/18939_2.png) [@eschereal](https://boards.straightdope.com/u/eschereal)\ **Post date:** [October 17, 2018, 10:14pm UTC](https://boards.straightdope.com/t/how-can-one-prove-that-the-earth-is-a-sphere-or-close-to-it/822973/81 "2018-10-17T22:14:59Z")
> [@Machine\_Elf](#): > > This would not explain [magnetic dip,](https://en.wikipedia.org/wiki/Magnetic_dip) particularly the fact that dip reaches 90 at the magnetic south pole (see map at link). But the common flat-earther won’t accept any measurements of this that he does not make for himself. More importantly, there is the magnetic declination, described in a link from your link. Explaining how that would make sense on a flat earth is stunningly difficult. The vertical bar magnet idea fails rather spectacularly. ---
**Author:** ![Limmin](https://avatars.discourse-cdn.com/v4/letter/l/f04885/32.png) [@Limmin](https://boards.straightdope.com/u/Limmin)\ **Post date:** [October 18, 2018, 12:45pm UTC](https://boards.straightdope.com/t/how-can-one-prove-that-the-earth-is-a-sphere-or-close-to-it/822973/82 "2018-10-18T12:45:17Z")
I agree that the premise should be flipped: The OP shouldn’t have to prove the Earth is round. This is well documented, our technological society functions well with this assumption. No, the burden of proof is on the flat-Earthers. Let them try to convince you. If they can’t, they’ll have to find a way to do it. Just ask simple questions requiring simple answers… - Where is the center of the earth? - How can you fly from Japan to California without overflying Europe or the Atlantic? - How does GPS work, in your opinion? - If gravity doesn’t exist, then explain how we’re not falling off the Earth? Etc. What is NOT convincing is to come up with more and more complex, convoluted explanations for what should be simple. If that’s the direction they’re heading, you can cut them off, saying “sorry, I don’t buy it, there’s a simpler explanation already.” Let them go into a tizzy, you don’t have to. ---
**Author:** ![scr4](https://avatars.discourse-cdn.com/v4/letter/s/59ef9b/32.png) [@scr4](https://boards.straightdope.com/u/scr4)\ **Post date:** [October 18, 2018, 12:51pm UTC](https://boards.straightdope.com/t/how-can-one-prove-that-the-earth-is-a-sphere-or-close-to-it/822973/83 "2018-10-18T12:51:15Z")
> [@Limmin](#): > > - Where is the center of the earth? The north pole. > [@](#): > > - How can you fly from Japan to California without overflying Europe or the Atlantic? Because the earth looks [like this](https://www.facebook.com/812852995431891/posts/flat-earth-map-with-an-arctic-in-its-center-as-the-true-north-surrounded-by-the-/1123506871033167/). > [@](#): > > - How does GPS work, in your opinion? Like Loran-C. > [@](#): > > - If gravity doesn’t exist, then explain how we’re not falling off the Earth? Gravity does exist. It pulls down. (Just playing devil’s advocate here…) ---
**Author:** ![beowulff](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/beowulff/32/542_2.png) [@beowulff](https://boards.straightdope.com/u/beowulff)\ **Post date:** [October 18, 2018, 1:36pm UTC](https://boards.straightdope.com/t/how-can-one-prove-that-the-earth-is-a-sphere-or-close-to-it/822973/84 "2018-10-18T13:36:29Z")
If the Earth is flat, why are the other planets spherical? Are we special? ---
**Author:** ![CookingWithGas](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/cookingwithgas/32/485_2.png) [@CookingWithGas](https://boards.straightdope.com/u/CookingWithGas)\ **Post date:** [October 18, 2018, 1:46pm UTC](https://boards.straightdope.com/t/how-can-one-prove-that-the-earth-is-a-sphere-or-close-to-it/822973/85 "2018-10-18T13:46:08Z")
> [@scr4](#): > > > [@](#): > > > > - How can you fly from Japan to California without overflying Europe or the Atlantic? > > Because the earth looks [like this](https://www.facebook.com/812852995431891/posts/flat-earth-map-with-an-arctic-in-its-center-as-the-true-north-surrounded-by-the-/1123506871033167/). In the flat earth, a flight from Sydney to Buenes Aires would be optimized to fly over the North Pole, but this doesn’t happen. (Playing Devil’s prosecutor.) Are all the airlines in on the conspiracy? ---
**Author:** ![Patch](https://avatars.discourse-cdn.com/v4/letter/p/a183cd/32.png) [@Patch](https://boards.straightdope.com/u/Patch)\ **Post date:** [October 18, 2018, 1:49pm UTC](https://boards.straightdope.com/t/how-can-one-prove-that-the-earth-is-a-sphere-or-close-to-it/822973/86 "2018-10-18T13:49:09Z")
> [@Saint\_Cad](#): > > Nope. I can get the same results with a flat Earth and a Sun at an altitude of 40722 stadia (around 5000 miles) Then your problem is the sun’s size in relation to an observer’s position. An observer A directly under the sun at noon, say, can measure the width of the sun in degrees with a solar telescope. At the same time, on some other part of the planet, another observer B can also measure the width of the sun in degrees. Their results will differ. It will differ for observers C, D, E, F, et al, as the sun is close enough the angles are easily measurable. In addition, if this particular flat earther asserts that the sun isn’t a sphere, then observer B will not see a round sun, but an ellipse. ---
**Author:** ![Brayne\_Ded](https://avatars.discourse-cdn.com/v4/letter/b/e9bcb4/32.png) [@Brayne\_Ded](https://boards.straightdope.com/u/Brayne_Ded)\ **Post date:** [October 18, 2018, 2:00pm UTC](https://boards.straightdope.com/t/how-can-one-prove-that-the-earth-is-a-sphere-or-close-to-it/822973/87 "2018-10-18T14:00:04Z")
> [@scr4](#): > > If you really want to know what they believe, the _Oh no, Ross and Carrie!_ podcast did interviews of [Mark Sargent](http://ohnopodcast.com/investigations/2017/11/30/ross-and-carrie-traverse-flat-earth-part-5-the-mark-sargent-interview) and [Jeran Campanella](http://ohnopodcast.com/investigations/2018/7/20/ross-and-carrie-traverse-flat-earth-part-7-the-jeran-campanella-interview). They also participated in some meetings and experiments with flat earthers - just search their [web site](http://ohnopodcast.com/) for “flat earth.” > > I think Mark Sargent seemed to imply that the sky is a giant artificial display that can show the stars, Moon, etc in any way they want us to see them. I remember Ross asking if it was like a lenticular display, showing different things depending on view angle, and he basically said yes. With this explanation they can dismiss pretty much any argument based on observing the sky. Oh, so the whole world is just a big version of “The Truman show”? Well, I never knew that, how stupid i must be. ---
**Author:** ![Patch](https://avatars.discourse-cdn.com/v4/letter/p/a183cd/32.png) [@Patch](https://boards.straightdope.com/u/Patch)\ **Post date:** [October 18, 2018, 2:02pm UTC](https://boards.straightdope.com/t/how-can-one-prove-that-the-earth-is-a-sphere-or-close-to-it/822973/88 "2018-10-18T14:02:48Z")
> [@cormac262](#): > > My girlfriend’s brother works with a guy who is a flat-earther. So much so that his daughter caused a stir in school by confronting her teacher who was showing a spherical earth. > This guy has been dying to “discuss” his view with me - with the challenge for me to prove him wrong. I mentioned him before, but check out [CoolHardLogic’s video series on flattards](https://www.youtube.com/user/CoolHardLogic/videos?disable_polymer=1). He very simply demonstrates the inanity of a flat earth position, and it’s presented in an easy to follow format, and some of the stuff you can do yourself (though it would involve some travel, but hey, no one said proving a global conspiracy wouldn’t involve a road trip). ---
**Author:** ![Machine\_Elf](https://avatars.discourse-cdn.com/v4/letter/m/82dd89/32.png) [@Machine\_Elf](https://boards.straightdope.com/u/Machine_Elf)\ **Post date:** [October 18, 2018, 2:59pm UTC](https://boards.straightdope.com/t/how-can-one-prove-that-the-earth-is-a-sphere-or-close-to-it/822973/89 "2018-10-18T14:59:59Z")
> [@CookingWithGas](#): > > In the flat earth, a flight from Sydney to Buenes Aires would be optimized to fly over the North Pole, but this doesn’t happen. (Playing Devil’s prosecutor.) Are all the airlines in on the conspiracy? If you ask about this, it appears to get ignored. See [discussion at this link](https://www.theflatearthsociety.org/forum/index.php?topic=67967.0), scroll down to reply #20, in which a participant posts screenshots of the Sydney/Johannesburg flight track from [www.flightradar24.com](http://www.flightradar24.com), illustrating a great-circle route (with distance and time) that agrees with what one would expect from a spherical earth. Nobody responds. If a flat-earther were to respond, my guess is that yes, they’d claim conspiracy. See my post upthread: to flat-earthers, flat earth is an incontrovertible universal constant, and all observations that conflict with it are either flawed or fraud. ---
**Author:** ![Limmin](https://avatars.discourse-cdn.com/v4/letter/l/f04885/32.png) [@Limmin](https://boards.straightdope.com/u/Limmin)\ **Post date:** [October 18, 2018, 4:24pm UTC](https://boards.straightdope.com/t/how-can-one-prove-that-the-earth-is-a-sphere-or-close-to-it/822973/90 "2018-10-18T16:24:14Z")
> [@scr4](#): > > The north pole. > Because the earth looks [like this](https://www.facebook.com/812852995431891/posts/flat-earth-map-with-an-arctic-in-its-center-as-the-true-north-surrounded-by-the-/1123506871033167/). > > Like Loran-C. > > Gravity does exist. It pulls down. > > (Just playing devil’s advocate here…) Exactly! And you can point out a counterexample or fallacy with each one, which the flat-earthers need to explain. Again, they need to come up with convincing proof, if they want to be believed “scientifically.” ---
**Author:** ![eschereal](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/eschereal/32/18939_2.png) [@eschereal](https://boards.straightdope.com/u/eschereal)\ **Post date:** [October 18, 2018, 5:08pm UTC](https://boards.straightdope.com/t/how-can-one-prove-that-the-earth-is-a-sphere-or-close-to-it/822973/91 "2018-10-18T17:08:33Z")
I read somewhere that gravity is an illusion, that the pizza/blister Earth is accelerating upward and when you fall, it is just the Earth catching up to you. Into what it is accelerating is unclear, because my impression is that FECTs believe that the pizza Earth and sparkly sky dome is the whole of reality: there is no unthinkably vast universe out there. Which I would find an incredibly depressing notion. The idea that we are an imperceptible mote in the immenseness of reality, amounting to nothing, bothers some people, but the apposite idea seems worse, to me. ---
**Author:** ![scr4](https://avatars.discourse-cdn.com/v4/letter/s/59ef9b/32.png) [@scr4](https://boards.straightdope.com/u/scr4)\ **Post date:** [October 18, 2018, 5:56pm UTC](https://boards.straightdope.com/t/how-can-one-prove-that-the-earth-is-a-sphere-or-close-to-it/822973/92 "2018-10-18T17:56:59Z")
> [@Limmin](#): > > Again, they need to come up with convincing proof, if they want to be believed “scientifically.” Mainly they want to feel important, by convincing themselves that they know something we don’t. They aren’t really looking to convince the rest of us. ---
**Author:** ![scr4](https://avatars.discourse-cdn.com/v4/letter/s/59ef9b/32.png) [@scr4](https://boards.straightdope.com/u/scr4)\ **Post date:** [October 18, 2018, 7:03pm UTC](https://boards.straightdope.com/t/how-can-one-prove-that-the-earth-is-a-sphere-or-close-to-it/822973/93 "2018-10-18T19:03:22Z")
> [@Machine\_Elf](#): > > If you ask about this, it appears to get ignored. See [discussion at this link](https://www.theflatearthsociety.org/forum/index.php?topic=67967.0), scroll down to reply #20, in which a participant posts screenshots of the Sydney/Johannesburg flight track from [www.flightradar24.com](http://www.flightradar24.com), illustrating a great-circle route (with distance and time) that agrees with what one would expect from a spherical earth. > > Nobody responds. > > If a flat-earther were to respond, my guess is that yes, they’d claim conspiracy. See my post upthread: to flat-earthers, flat earth is an incontrovertible universal constant, and all observations that conflict with it are either flawed or fraud. Right, they’d probably just say “I’ve never been on that flight, have you?! How do you know that tracking information is real??” ---
**Author:** ![coffeecat](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/coffeecat/32/3405_2.png) [@coffeecat](https://boards.straightdope.com/u/coffeecat)\ **Post date:** [October 18, 2018, 7:03pm UTC](https://boards.straightdope.com/t/how-can-one-prove-that-the-earth-is-a-sphere-or-close-to-it/822973/94 "2018-10-18T19:03:56Z")
> [@Limmin](#): > > - If gravity doesn’t exist, then explain how we’re not falling off the Earth? Old comedy routine— “Dear Mr. Answer Man: If the world is round, why don’t people on the other side fall off?” “Your question betrays a common misconception. People are falling off all the time.” ---
**Author:** ![Patch](https://avatars.discourse-cdn.com/v4/letter/p/a183cd/32.png) [@Patch](https://boards.straightdope.com/u/Patch)\ **Post date:** [October 18, 2018, 7:52pm UTC](https://boards.straightdope.com/t/how-can-one-prove-that-the-earth-is-a-sphere-or-close-to-it/822973/95 "2018-10-18T19:52:38Z")
> [@coffeecat](#): > > Old comedy routine— > > “Dear Mr. Answer Man: If the world is round, why don’t people on the other side fall off?” > “Your question betrays a common misconception. People are falling off all the time.” One thing I liked about the Discworld books was the adventure at the ocean along the edge of the world (can’t remember the book, one of the early ones with the Traveller?) where the guy built the machine to travel over the edge to see what lay beyond, and the residents on the edge had rope lines across the lip to catch debris for useful items. ---
**Author:** ![Chronos](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chronos/32/134_2.png) [@Chronos](https://boards.straightdope.com/u/Chronos)\ **Post date:** [October 18, 2018, 7:54pm UTC](https://boards.straightdope.com/t/how-can-one-prove-that-the-earth-is-a-sphere-or-close-to-it/822973/96 "2018-10-18T19:54:40Z")
Or if you were on that flight, well, you weren’t the pilot, were you? ---
**Author:** ![Machine\_Elf](https://avatars.discourse-cdn.com/v4/letter/m/82dd89/32.png) [@Machine\_Elf](https://boards.straightdope.com/u/Machine_Elf)\ **Post date:** [October 18, 2018, 8:25pm UTC](https://boards.straightdope.com/t/how-can-one-prove-that-the-earth-is-a-sphere-or-close-to-it/822973/97 "2018-10-18T20:25:09Z")
Relevant to flat earthers’ thought processes and the reason nothing you could ever do will convince them the earth is spherical: > **[Denialism](https://en.wikipedia.org/wiki/Denialism)** > > In the psychology of human behavior, denialism is a person's choice to deny reality as a way to avoid a psychologically uncomfortable truth. Denialism is an essentially irrational action that withholds the validation of a historical experience or event when a person refuses to accept an empirically verifiable reality. > In the sciences, denialism is the rejection of basic facts and concepts that are undisputed, well-supported parts of the scientific consensus on a subject, in favor of ideas that... ---
**Author:** ![DesertDog](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/desertdog/32/11503_2.png) [@DesertDog](https://boards.straightdope.com/u/DesertDog)\ **Post date:** [October 19, 2018, 3:38pm UTC](https://boards.straightdope.com/t/how-can-one-prove-that-the-earth-is-a-sphere-or-close-to-it/822973/98 "2018-10-19T15:38:01Z")
The ability of flat-earthers to hand-wave away those pesky facts is impressive. Just last night I was watching YouTube video where the channel-owner read an e-mail from a guy who claimed to have visited the Antarctic Wall. Of course, all verifiable information had been elided for “privacy reasons.” ---
**Author:** ![eschereal](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/eschereal/32/18939_2.png) [@eschereal](https://boards.straightdope.com/u/eschereal)\ **Post date:** [October 19, 2018, 5:15pm UTC](https://boards.straightdope.com/t/how-can-one-prove-that-the-earth-is-a-sphere-or-close-to-it/822973/99 "2018-10-19T17:15:40Z")
I just watched about two thirds of that video, and it leaves me with an enormous question. The narrative states that the reporter is under threat from foreign governments, so he has to keep a low profile. So, if the world were in fact flat, and all these globalist conspirators are working together (a dubious notion in the first place, based on the inability of large international groups to actually collaborate) to dupe us into believing in a ball Earth, what exactly do the globalists gain by perpetrating the fiction? ---
**Author:** ![x-ray\_vision](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/x-ray_vision/32/351_2.png) [@x-ray\_vision](https://boards.straightdope.com/u/x-ray_vision)\ **Post date:** [October 19, 2018, 6:09pm UTC](https://boards.straightdope.com/t/how-can-one-prove-that-the-earth-is-a-sphere-or-close-to-it/822973/100 "2018-10-19T18:09:48Z")
> [@eschereal](#): > > So, if the world were in fact flat, and all these globalist conspirators are working together (a dubious notion in the first place, based on the inability of large international groups to actually collaborate) to dupe us into believing in a ball Earth, what exactly do the globalists gain by perpetrating the fiction? The reason I’ve heard from various flat-earthers is basically the one given here: > [@](#): > > Perhaps the most ridiculous came from Mark Sargent, a famous flat-earther who came to prominence with a series of YouTube videos in 2015 when he was asked why the scientific community won’t come clean about the Earth being flat. > > Sargent told the man who posed the question that governments and scientists cannot admit the “truth” because society as we know it would collapse. > > “Because by the time they figured it out … the industrialized world — the cement was already cast,” said Sargent, according to the _Edmonton Journal_ piece. > > Sargent continued by stating: “If some scientist revealed it tomorrow on CNN, or whatever, and it was broadcast that the Earth is not (round) — there’s potential for some real shock waves, some real upheaval. The first one is academic — literally in every university in every country, astrophysics and astronomy would have to be shut down overnight. Those would not reopen.” [https://www.brainjet.com/world/2456216/the-real-reason-scientists-are-lying-about-the-earth-being-round-according-to-flat-earthers/](https://www.brainjet.com/world/2456216/the-real-reason-scientists-are-lying-about-the-earth-being-round-according-to-flat-earthers/) [Previous page](https://boards.straightdope.com/t/how-can-one-prove-that-the-earth-is-a-sphere-or-close-to-it/822973.md?page=4) [Next page](https://boards.straightdope.com/t/how-can-one-prove-that-the-earth-is-a-sphere-or-close-to-it/822973.md?page=6)