Flat Earth debunks - The Earth

{{pseudoastronomy}}
{{ArticleSeries|Flat Earth|the Flat Earth}}

[[Flat_Earth|Flat-Earthers]] have made several incorrect observations to claim the Earth is flat. This article refutes claims made by flat-Earthers about our planet itself.
== The Curve ==
==="But roads are flat!"===
[[File:Overlooking the Bonneville Salt Flats from Wendover, NV.jpg|thumb|Interstate 80 traverses the {{wpl|Bonneville Salt Flats}}, Utah. Despite being a "flat" surface the highway is curved following Earth’s curvature.<ref>Pilling, Michelle (Feb. 24, 2012). [https://www.flickr.com/photos/gopher21479/6780533836/in/photostream/ "Overlooking the Bonneville Salt Flats from Wendover, NV. Very noisy, no tripod"]. Via flickr.com</ref>]]

A common trope in flat-earther literature is that roads, canals, etc. are built flat &mdash; not taking into account the curvature of the Earth.<ref>[http://www.atlanteanconspiracy.com/2015/05/architects-engineers-for-flat-earth.html Architects & Engineers for Flat Earth Truth]. atlanteanconspiracy.com, 13 July 2016.</ref> There are a number of issues with this:

Firstly, {{wpl|Surveying|surveyors}} ignore curvature when surveying a project with relatively short baselines because the error from ignoring curvature is minuscule. They do, however, consider curvature in creating small-scale maps. Some construction projects actually do take into account the curvature of the Earth, such as [[Japan]]'s Proton Accelerator Complex<ref>K. Mishima, N. Tani, and M. Sirakata, [http://www.slac.stanford.edu/econf/C06092511/presents/TU004_PPT.PDF Survey and Alignment of J-PARC]. slac.stanford.edu, 2006.</ref><ref>Kenji Mishima and Norio Tani, [http://www.slac.stanford.edu/econf/C04100411/papers/010.PDF Geodetic Survey Work on High Intensity Proton Accelerator Facility]. IWAA2004, CERN, Geneva, 4-7 October 2004.</ref> and the [[Large Hadron Collider]] (LHC).<ref>Peter Kenyon, [https://www.tunneltalk.com/CERN-10Dec2014-Future-Circular-Collider-preliminary-alignment-studies.php Designing a 100km collider tunnel for CERN]. tunneltalk.com, 10 December 2014.</ref> Some roads can be seen curving around the Earth surface, for example {{wpl|Lake Pontchartrain Causeway}}<ref>{{Cite AV media |url=https://www.youtube.com/watch?si=kCpT2koF96dLTXvD&v=5yk6aTrjYmg&feature=youtu.be |title=What We Saw Through Soundly's Telescope From My 15th Floor Window At 5pm On Dec 10, 2017 |date=2022-06-17 |last=Jesse Kozlowski |access-date=2025-02-02 |via=YouTube}}</ref> and the interstate 80 of the {{wpl|Bonneville Salt Flats}}<ref>{{Cite web|title=The Curvature of the Earth - Bonneville Salt Flats (from West Wendover) |url=https://www.youtube.com/watch?v=-EiOrBd_rog |access-date=2023-08-24 |language=en}}</ref> (how [[ironic]]).<ref group=note>Of course, those useless projects are all just designed by people in on the conspiracy. [[Pigeon chess|Checkmate, losers!]]</ref>

Secondly, for a mile-long baseline, the drop will only be 8 inches. The length of the hypotenuse of a right triangle with one leg of 5280 feet and the other leg of 8 inches is 5280.00004209 feet. The error in length is 0.013 millimeters. This error is so small that if you built a road going all the way around the Earth, using one mile long baselines, the total error in length would amount to 1.05 feet. See the table below to get a grasp about at which distances the curve starts to matter:

{{collapse|Curvature drop calculus|width=500}}
Using the exact equation for curvature drop from [https://walter.bislins.ch/bloge/index.asp?page=Advanced+Earth+Curvature+Calculator Advanced Earth Curvature Calculator]

[[File:Exact curvature drop formula.svg|220px]]
<!-- <math>\text{drop} = R^{'} \cdot \left [  1-cos \left( \frac{d}{R^{'}}\right )  \right ]</math> -->

with

[[File:Exact curvature drop formula r.svg|100px]]
<!-- <math>R^{'} = \frac{R}{1-k}</math> -->

where

* '''d''' = distance, 
* '''R'''' = the refracted radius of the Earth, 
* '''R''' = the radius of Earth without refraction (6,371,000m), and
* '''k''' = refraction coefficient (0)

we get the following table:

{| class="wikitable"
|+ Curvature drop table
|-
! Distance !! Drop !! Drop is roughly the size of
|-
| 1,000 km || 78.320 km || Drive from Washington to Baltimore
|-
| 100 km || 784.790 m || Burj Khalifa
|-
| 10 km ||  7.848 m || A stretch limousine
|-
| 1 mi || 8.003 in || A pencil
|-
| 1 km || 7.848 cm || A hamster
|-
| 100 m || 784.806 μm || A dust mite
|-
| 10 m || 7.848 μm || Red blood cell
|-
| 1 m || 78.513 nm || Transistor size in CPU
|-
| 10 cm || 707.323 pm || A {{wpl|Benzene|benzene}} molecule
|-
| 59 mm || 273.191 pm || The width of water molecule (270pm)
|-
| 1 cm || 7.848 pm || The charge radius of proton
|}
{{collapse end}}

Finally, surveyors can measure Earth's curvature on roads using reciprocal vertical/zenith angles,<ref>{{Cite journal |last=Johnson |first=A. L. |year=2008 |title=Do reciprocal vertical angles have a role in Geomatics? |url=https://www.researchgate.net/publication/233674994_Do_Reciprocal_Vertical_Angles_have_a_role_in_Geomatics |journal=Survey Review |language=en |volume=40 |issue=309 |pages=285–293 |doi=10.1179/003962608X325358 |issn=0039-6265}}</ref><ref>{{Cite web |title=Determining the Shape of the Earth with Zenith Angle Measurements |url=https://walter.bislins.ch/bloge/index.asp?page=Determining+the+Shape+of+the+Earth+with+Zenith+Angle+Measurements |website=Walter Bislin's Blog-En}}</ref><ref>{{Cite web |last=Kozlowski |first=Jesse |date=2020-06-09 |title=Reciprocal Zenith Angle Projects |url=https://jessekozlowski.wordpress.com/2020/06/09/reciprocal-zenith-angle-projects/ |access-date=2024-08-26 |website=Jesse Kozlowski, Surveyor |language=en}}</ref> i.e., measure the zenith angles between two points. If the Earth is flat, the sum of the zenith angles will be 180°. But all measurements show then sum of angles is more than 180°, proving the Earth a globe. In fact, the distance between the two points can even be used to calculate the radius of the Earth.<ref>{{Cite web |date=2019-10-14 |title=Confirming the Earth is spherical using reciprocal zenith angles |url=https://mctoon.net/radius-reciprocal-angles/ |access-date=2024-08-26 |website=MCToon |language=en}}</ref>

==="But water is always level!"===

[[File:Lake Pontchartrain Causeway From Three Lakeway Center2.jpg|thumb|This photo of the {{wpl|Lake Pontchartrain Causeway}} demonstrates the Earth's curvature by showing the bridge curving along the lake and going under the horizon, thus proving that "level" isn't the same as flat. Flerfs like [https://youtu.be/J7RwAcL4Iq0?si=MdgptNoWkCIPMfPC&t=10071 Dubay] have claimed there's too little curvature near the camera, and too much curvature at the end, proving he doesn't understand what the '''²''' in the '''8 in / mi²''' formula means: Exponential growth.]]

Same point from above. Flat-earthers wrongly assume that a "level" surface is the same as a "flat" surface and they often [[argumentum ad dictionarium|use a dictionary entry]] as evidence for it. But of course, just like [[creationist]]s (which they often are) misusing the word "[[just a theory|theory]]", flat-earthers ignore the context in which they are talking (basically [[physics]], topology and surveying). 
* [https://www.merriam-webster.com/dictionary/level Merriam-Webster] defines "level" as: "''conforming to the curvature of the liquid parts of the earth's surface''". 
* [https://www.thefreedictionary.com/Level+surface The Free Dictionary] defines a "level surface" as: "''(Physics) an equipotential surface at right angles at every point to the lines of force''". 
* As in [https://civilengineeringx.com/surveying/terms-used-in-levelling/ civilengineeringx.com] is explained: "''a surface parallel to the mean spheroid of the Earth is called a level surface and the line drawn on the level surface is known as a level line. Hence all points lying on a level surface are equidistant from the centre of Earth.''" So yeah, water is indeed level, not flat.
* This point has been understood for centuries and ''Universal Cyclopaedia'' from 1894 put it this way:

{{cquote|'''A level surface''' is ordinarily conceived as a plane, but it really represents a certain equilibrium of attractive and rotational forces, and '''is always curved'''.<ref name=":Cyclopaedia">{{Cite book |url=https://books.google.es/books?id=01cc5UXxhocC&pg=PA886#v=onepage&q&f=false |title=Johnson's Universal Cyclopaedia: A New Edition |date=1894 |publisher=A. J. Johnson Company |pages=887 |language=en}}</ref>}}

* The 1806 edition of the book ''A Treatise of Practical Surveying'' by Robert Gibson states on [https://archive.org/details/atreatisepracti02gibsgoog/page/n283/mode/2up?q=level page 283]: "''The true level is a curve conforming to the surface of the earth;''". As it precedes the OG flat earther {{wpl|Samuel_Rowbotham|Samuel Rowbotham}} by a decade, every flat-earther has had ample opportunity to familiarize themselves with what the field of surveying considers the word ''level'' to mean.

Furthermore, if we were to assume that water is always "level" (that is, as flat, never curving and always at the same altitude) then on a flat Earth the ocean tides would be impossible. In all parts of the world, they should rise and lower equally. This is obviously not the case. So, even on Discworld, water would still be not "level". See also the following experiments:

* [[Alfred_Russel_Wallace|Alfred Russell Wallace's]] improved [[Bedford_Level_experiment#Alfred_Russel_Wallace.27s_Reproduction_.281870.29|replication]] of Rowbotham's [[Bedford_Level_experiment#Samuel_Rowbotham.27s_Experiment_.281838.29|Bedford Level Experiment]].
*[[Lake_Minnewanka_curve_experiment|Dan Olson's Lake Minnewanka Curve Experiment]].
*[[Flat_Earth#Jesse_Kozlowski.27s_Cooper_River_Lake_Curve_Experiment_.282016.29|Jesse Kozlowski's Cooper River Lake Curve Experiment]].

<u>'''''TLDR:'''''
</u>
{{collapse|True level only exists in cartoons|width=500}}
<center>{{#ev:youtube|https://youtu.be/o8ym0HBvpFA|||||start=21}}
{{collapse end}}

A common [[escape hatch]] that flat-earthers do, is claim that ''"water can't bend or stick to a sphere"''. More on that [[Flat_Earth_debunks_-_The_Earth#.22So_how_can_water_stick_to_a_spinning_ball.3F.22|here]].

=== "But Kansas is flatter than a pancake!" ===
[[File:Pancake-640869 1920.jpg|thumb|right|200px|There's a visible curvature on those flat pancakes!]]
Often cited (e.g. Eric Dubay [https://youtu.be/ymdtjsu7HiM?si=HwtT6y_qbJ2nE8zg&t=213 here]) is a topographical paper where a geodetic survey (which is “a survey of a large land area in which corrections are made for the curvature of the earth’s surface” by the way...)<ref>{{Cite web |title=Definition of GEODETIC SURVEY |url=https://www.merriam-webster.com/dictionary/geodetic+survey |access-date=2023-04-29 |website=www.merriam-webster.com |language=en}}</ref> was done on Kansas and established it has a flatness ratio of 0.9997 while a pancake comes in at 0.957.<ref>{{Cite web |title=Zero Gravity: The Lighter Side of Science |url=http://www.aps.org/publications/apsnews/200310/pancake-kansas.cfm |access-date=2023-04-29 |website=www.aps.org |language=en}}</ref>

Once again, flat-earthers don't think big nor understand scales. [[Kansas]] is 410 miles wide, which is 1.65% of Earth's circumference, or just 5.93º of arc. Yeah... There can be pancakes less flat than that... In any case, what geologists mean by “flat” is often “smooth”, as the opposite of {{wpl|Terrain|relief|.}}<ref>{{Cite web |title=Relief. Project.geo.msu.edu |url=https://project.geo.msu.edu/geogmich/Relief.html |access-date=2023-04-29 |website=project.geo.msu.edu}}</ref> To compare on a bigger scale, if Earth were shrunk to bowling-ball size, Mount Everest would be about half the size of a grain of salt (0.15 mm).<ref name=":billiard">{{Cite web |last=Nevres |first=M. Özgür |date=2017-08-17 |title=No, Earth is not as smooth as a billiard ball! [Here’s why] |url=https://ourplnt.com/earth-smooth-billiard-ball/ |access-date=2023-04-29 |website=Our Planet |language=en-us}}</ref>

==="But ''"table experiments"'' prove it just looks like there's curvature!"===

[[File:Lego curvature.jpg|thumb|right|A screenshot from the lego video shows the purported "curvature".]]

Flat-earthers try to prove their beliefs with videos a simple "experiment" involving a flat table, a camera "eye level" to the table (more on that later...) and objects on the table, like a coin. The gist is that when the coin is close to the camera it's visible but then the coin appears to disappear by going under the table when they move it further away from it; thus proving the "curvature" is an illusion. 

Dave McKeegan [https://www.youtube.com/watch?v=1cZgGOPUEDs&t refuted] these flat-earthers' "experiments" by proving that on their videos the camera is slightly below and not "level" to the table, thus being physically obstructed by the table, which on the real world is equivalent to be underground. Flatties might as well cheat while playing solitaire. Once we put the camera level to the table or on top of it (which is more realistic since we don't live lying down on the ground) this "experiment" becomes ''busted''!

A [https://youtu.be/PqFN-_xwyF8?si=Jq1B8KPflZmTeqwp&t=438 variant] of the "experiment" from above that Eric Dubay [https://youtu.be/J7RwAcL4Iq0?si=WiZJWfLR3o3M-OYm&t=10113 co-signed] shows lego bricks on a table displaying curvature on a flat surface. It's immediately clear, that the filmer is extremely careful to not show the table from high altitude to avoid revealing the game. Also, [https://youtu.be/PqFN-_xwyF8?si=VJu4kLJutPstkLaC&t=477 some frames of the video] show horizontal bright lines on the table's surface. These lines can not be explained away as specular reflections because the light would have to originate from the matte chair behind the table. The conclusion, which's shared by [https://flatearthdelusion-blogspot-com.translate.goog/2017/07/la-curvatura-terrestre-ed-il-lago.html?_x_tr_sl=it&_x_tr_tl=en this debunk], is that the table consists of three segments that bend, and introduce slight curve. Thus, the bright horizontal line in the table comes from light being reflected from the middle segment's edge. It's also evident from the original video's green bottom highlight [https://youtu.be/PqFN-_xwyF8?si=nyz-6m7VjCE6HCV3&t=504 at this point] that looks like a lazy approximation, but is actually pretty much exactly the curvature a three-part table creates.

When the experiment was [https://www.youtube.com/watch?v=WJavyIWROcc reproduced] without hiding the shape of the table, the curve suddenly disappeared. Flerfs are of course free to show this again, this time without poor camera work, and with surfaces that are shown to be flat, with brick towers that are 1) proven to be equally tall, and 2) aligned to not create sideways curvature. We globers won't be holding our breaths.

==="But football fields prove it just looks like there's curvature!"===

There is [https://www.reddit.com/r/flatearth/comments/iws90u/haters_will_say_the_football_field_is_curved_it/ another widespread video used in flat Earth groups] of a guy recording himself on an American football field walking across it. The video starts with the guy putting the camera on the football field ground and he goes away from the camera he appears to go underground. This is evidence for them of "perspective" hiding objects under the horizon. 

In reality, American football fields are not flat so water can be drained more easily. This is even clearer when the field is flooded (see [https://www.foxnews.com/us/california-football-field-flooded-water-tropical-storm-hilary-pours-rain-region here], [https://www.diehardsport.com/college-football/michigan/michigan-utah-game-gets-suspended-michigan-stadium-field-floods/ here] or [https://www.ncaa.com/news/football/article/2017-10-14/western-michigan-footballs-homecoming-game-against-akron-postponed here]). So, in actuality, flat-earthers have {{wpl|own goal|own goaled}}themselves here (pun intended).

This recommendation for the amount of slope in the field can also be found in the literature. E.g., the book ''Sports Fields: A Manual for Design, Construction and Maintenance'' by Puhalla et al. [https://books.google.com/books?id=szBM9Xi9vdMC&lpg=PA81&pg=PA103#v=onepage&q&f=false states] on page 131, "''The typical percentage of slope for a sports field runs between 1% and 1.75%.''" The same goes for soccer, where the ''NFHS soccer rules book'' [https://ihsaa-static.s3.amazonaws.com/soccer/2012-13%20Soccer%20Rules.pdf#page=9 states] that "''An engineered natural turf soccer field should have a minimum of one-and-one-half percent (1.5%) slope for fields which are surface drained. For natural turf fields with a sub-surface drain system the slope should be no less than one (1.0%) percent. For synthetic turf fields with a sub-surface drain system the slope should be no less than one half of one (0.5%) percent.''"

The fact is perspective can't make you disappear bottom up and you can test that by recording yourself walking away from a big corridor.

==="But the horizon is always at eye level!"===

[[File:Boeing747-400 clock, RMI, PFD, ND.jpg|thumb|200px|Pilots need attitude indicators or "artificial horizons" (the blue display) to account the relationship of the aircraft relative to the actual horizon.]]
Rather, it ''looks'' like it is. Ignoring for a moment the fact that an eye-level horizon would have to ''rise'' two meters over the distance between itself and the observer, the thing about Earth is it's actually quite big (no, seriously!).

[[File:Horizons.svg|thumb|350px|center|Names of different horizons.]]

There are two kinds of the horizon: 
* '''Astronomical horizon''' (90° from the plumb line) AKA eye-level, and 
* '''True horizon''' (the line where sky meets Earth or the ocean). 

Because the Earth is a sphere, the true horizon always lies below the astronomical horizon. The angle between them is the '''dip of the horizon'''. The higher the observer, the larger the dip of the horizon.

Actually, if you're ever out at sea, you can quite easily notice the dip. Fix a long object to point toward the horizon, and then look along it the other way. You'll notice the object points slightly above the opposite horizon, demonstrating that it really is slightly below eye level.

Indeed, from a height of 3 metres above sea level, assuming an Earth radius of 6371 km, the horizon is about 0° 3′ 20″ (0.0556° if you don't speak arcminutes) below eye level.

If we are at a significant altitude from the surface (like on top of a mountain or on an airplane) we can observe the dip of the horizon with a precise instrument like a theodolite<ref group=note>Flerfs agree [https://youtu.be/lD-uBaoiNE8?si=k5Ma7EV7JePC6EfQ&t=35 agree] theodolites are accurate.</ref> (or even a bottle of water for crying out loud!).<ref>[https://flatearth.ws/c/horizon-dip Dip of the Horizon] ''FlatEarth.ws''.</ref>

{{collapse|Videos showing horizon drop|width=500}}

Perspective lines show the horizon's dip:
{{video|youtube|aisuqNIzXCs}}

Flat-earthers like [https://youtu.be/cAr7yWnTBDY?si=5r0PPdt_lXAmJgNH&t=613 Eric Dubay] like to share drawings where a hose level shows its surface at the level of true horizon. Let's see how well that plays out in real life:
{{video|youtube|NqOQ_BCtqUI}}

Theodolites also clearly show the dip, both the instruments…
{{video|youtube|IqAZuqSSmfw}}
{{video|youtube|sW591rNCF_U}}

…and smartphone apps.
{{video|youtube|Hh6Ryt3-1q8}}
{{video|youtube|F4SwHsv3bdw}}

{{collapse end}}

==="But objects go under the horizon due to perspective!"===

[[File:Curvatura 3.gif|thumb|right|250px|Ship disappearing over the horizon. This happens because the ship is obscured by the curvature of the Earth.]]

Perhaps the best (and oldest) way to prove there is a curvature is the fact we can't see distant objects, since if the Earth were truly flat, a sufficiently advanced telescope ought to be able to see all the way to {{wpl|Madagascar}} from [[Alaska]]. Instead, what actually happens, is we fail to see the lower parts of distant objects like buildings or mountains, and we see ships sailing into the distance disappear hull-first — an observation that first tipped off the ancients themselves. {{wpl|Ptolemy|Ptolemy}} in his {{wpl|Almagest|Almagest|,}} Book 1, Chapter 4:

{{cquote|[If the Earth was cylindrical,] then never would any of the stars be always visible to any of the inhabitants of the curved surface, but either all the stars would both rise and set for observers or the same stars for an equal distance from either of the poles would always be invisible to all observers. Yet the more we advance towards the north pole, the more the southern stars are hidden and the northern stars appear. So it is clear that here the curvature of the earth covering parts uniformly in oblique directions proves its spherical form on every side. Again, whenever we sail towards mountains or any high places from whatever angle and in whatever direction, we see their bulk little by little increasing as if they were arising from the sea, whereas before they seemed submerged because of the curvature of the water's surface.|||[https://bertie.ccsu.edu/naturesci/cosmology/ptolemy.html Almagest by Ptolemy] (c. 150 CE)}}

Dubay has [https://youtu.be/SauZfMS-lZo?feature=shared&t=16118 claimed]: "''If a ship's hull is 10 feet above the water, it will disappear from the innated eye at 6 miles. This has nothing to do with the supposed curvature of the Earth, and everything to do with the common law of perspective.''" This perspective "solution" is a non-starter since, in graphical perspective, everything above the horizon line will converge to the vanishing point but never reach it, let alone go under it (which is the very same phenomenon they are trying to explain in the first place!). It's mathematically impossible. Also, it begs the question, why is the stern/stem edge of the hull, which is closer to the observer than the ship's bridge, disappearing first? Shouldn't the thing that's closest to the observer remain visible the longest? Only on globe Earth model does the hull disappear first, because it's not about the resolvability of distant objects, but about the obstruction imposed by the curve.

Dubay has also [https://youtu.be/SauZfMS-lZo?feature=shared&t=15876 claimed] that flat Earth will also have distant people disappear feet first. So here's some 4K footage from the Bonneville salt flats to show that's not the case:
{{collapse|4K footage from Bonneville Salt Flats |width=500}}

First, two videos with a bunch of people. Regardless of distance, the proportions of humans remain correct, even at long distances. Also, they absolutely aren't disappearing their feet first, as the shoes are distinctively visible on the pale, salt-covered ground.
{{#ev:youtube|https://youtu.be/cLnJ6v6LTrQ|||||start=122}}
{{#ev:youtube|https://www.youtube.com/watch?v=w5p5KpWL378|||||start=41}}

Finally, some cars with trailers with protruding wheels are visible. It's easy to see the wheels never disappear, everything just reduces in size due to perspective.
{{#ev:youtube|https://youtu.be/TnGMaWVTux0|||||start=482}}
{{collapse end}}

Finally, here is a video showing the {{wpl|Walney_Wind_Farm|Walney Wind Farm}} on a day with very low atmospheric refraction. Notice how the blades effortlessly seem to dip into sea as they disappear behind the curve:
{{collapse|Walney Wind Farm|width=500}}
{{#ev:youtube|https://www.youtube.com/watch?v=-1_DFf2Jxxo|||||start=0}}
{{collapse end}}

==== "But you can zoom back the boats in view!" ====

Flat-earthers, like [https://youtu.be/-Ax_YpQsy88?t=4872 Dubay] before, have presented videos of people zooming in towards the horizon and then boats on it become visible again ([https://www.youtube.com/watch?v=ql_TTguKxnE&ab_channel=Zoominginonstuff example]), but this a big misunderstanding. What's really going on is that those boats were already visible but due to their far distance, their angular resolution is so small that it would be less than a pixel wide for the camera frame. Zooming in will increase their angular resolution and that will make it "pop up" in view again.

In order for flatties to hold that claim what they really need to do is to take a video of a boat whose hull is under the horizon, then zoom in and show back its full hull again. But they can't. Surprise?

Turns out, the only possible way to see further and bring back boats in view is by raising the observers' height. This makes sense on the globe since you are accounting for the curvature obstructing the boats, but, not so much on Discworld since, after all, the observers' distance from the boat would still be the same (if not further away).

<gallery>
File:Souter Lighthouse from the East - geograph.org.uk - 162194.jpg|Souter Lighthouse is 25m high and sits on cliffs which are themselves 25m above sea level 
File:Observe the curvature of the Earth from Newbiggin-by-the-Sea 2 - geograph.org.uk - 6808541.jpg|It is visible about 16 miles across the sea from Newbiggin.
File:Observe the curvature of the Earth from Newbiggin-by-the-Sea - geograph.org.uk - 6808561.jpg|However, close to sea level, and to the same scale, the 12m high 'hill' of water leaves only the top half of the lighthouse itself visible.
</gallery>

==="But the distance of the horizon is determined on clear weather by the power of our vision!"===

This  [https://youtu.be/SauZfMS-lZo?feature=shared&t=16184 comes from] Eric Dubay.

So, here is some 4K drone footage from a '''very''' clear day in Fiji. Notice that—

# From the ground it can be observed the drone is moving backwards, increasing distance to the horizon.
# The drone is gaining altitude. This also slightly grows the distance to the sea's surface at the horizon.<ref group=note>Think Pythagorean theorem where hypotenuse grows as height leg grows.</ref>
# From the ground it can be seen that more objects appear to left and right of the field of view, thus, the drone is not optically zooming.
# Since the drone is moving backwards, and since it's not optically zooming, there's nothing that would make it see further. 
# Therefore, by Dubay's logic, the horizon should be retreating.

And yet, the video shows, that as the drone gains altitude, the space between the furthest cliffs on left, and the horizon, quadruples.
This is only explained if the drone brings more sea into vision from behind the curve.
{{collapse|8 Hour drone film: "Islands From Above" 4K|width=500}}
{{#ev:youtube|https://youtu.be/b7Cl7S0pLRw|||||start=12847}}
{{collapse end}}

==== "But sunsets are caused by perspective!" ====
[[File:Sunset Beach Eclipse May 20th 2012.jpg|thumb|right|Montage of the Solar eclipse of 2012 taken with a solar filter. As the Sun sets its size never changes.|left]]
The very simple phenomenon of sunset is pain in the ass for flat-earthers suporting a small local sun. Afterall, how could the Sun appeared to be hiding under the horizon if it'd always be literally above us? The flat-earthers' partisan excuse is, once again, "perspective". That is, "the Sun is ''too far away'' to be seen". Usually this is followed by pictures of streetlights on a road converging due to perspective. This same excuse is also used for everything that apears to hide under the horizon. 

If that was the case, then the Sun would change its size along the day, getting smaller as it sets. Flat-earthers bring as proof timelapses of sunsets where the glare of the Sun reduces as it sets. However, this is caused by overexposure.  

<gallery mode="packed">
File:The sun1.jpg|In many pictures the Sun can look huge...
File:Solar eclipse & welding glass 2015-03-20.jpg|...but that's just glare. In reality, it's very small.
</gallery>

Once the camera settings are corrected and solar filter is used it can be clearly seen that the Sun disc doesn't decrease its size during the day:<ref>{{Cite web |title=sun-glare |url=https://flatearth.ws/t/sun-glare |access-date=2025-01-08 |website=FlatEarth.ws |language=en-US}}</ref><ref>{{Cite web |date=2019-05-08 |title=Flat-Earth “Perspective” is not Real-World Perspective |url=https://flatearth.ws/perspective |access-date=2025-01-08 |website=FlatEarth.ws |language=en-US}}</ref>

{{collapse|Sunset with and without the Solar Filter|width=500}}
{{#ev:youtube|https://www.youtube.com/watch?v=LFTWGdR8SiU|||||start=0}}
{{collapse end}}

===The sunset can be re-experienced by gaining altitude===

The flat Earth model states that the sunset results from the Sun moving away from us. Yet, we can easily bring the Sun back into view by going only higher:

{{collapse|Watching A Sunset Twice From A Drone|width=500}}
{{#ev:youtube|https://www.youtube.com/watch?v=xqAOsI2Ekf0|||||start=0}}
{{collapse end}}

Flat-earthers [https://wiki.tfes.org/Viewing_Distance claim] the reason we can see further as we rise higher, is because the change in perspective increases the angular size of the objects on the ground. This completely fails to explain the Sun re-appearing. In the flat Earth model, the Sun is obviously always higher than the drone, thus, increasing altitude would actually reduce the angular size. If you don't believe us, try filming the bottom of your table, and raise the camera slowly: do you see more of that bottom?

===="But you can zoom the set Sun back into view!"====

Same thing as before, but with the Sun. Eric Dubay shared a [https://youtu.be/J7RwAcL4Iq0?si=Vj1S42djduYlGzYh&t=11629 video] that gives the impression that Sun can be zoomed back into view. The extreme amount of bloom in the video is most likely due to high precipitation level. The video fails in its demonstration because it did not use a solar filter to remove the bloom. This is of course objectively false anyway, as demonstrated by Wolfie6020 with — once the flerfs' go-to DSLR — the Nikon P900:

{{collapse|Flat Earth - P900 Maximum zoom does not change the time of Sunset|width=500}}
Below is the side-by-side comparison of the [https://www.youtube.com/watch?v=KuV3roqT7j0 original footage].
<center>{{#ev:youtube|https://www.youtube.com/watch?v=bcKUNLkzmwU|||||start=0}}</center>
{{collapse end}}

==="So where's the curve?"===
[[File:Flat Earther Logic.jpeg|thumb|right|200px|Flat Earth logic against NBA.<ref>https://www.boredpanda.com/flat-earth-basketball-logic-uselesspickles/</ref>]]

A lot of flat-earthers attempt to disprove the globe model by using pictures taken from high above the Earth with a flat horizon, thereby "proving" that the Earth is flat: after all, if the Earth is round you should see the curvature of the earth.

Once again, flatties can't understand that Earth is ''really'' big, at least compared to us tiny human beings. The pictures that flat-earthers tend to provide as evidence are "only" captured from high-altitude balloons that are barely, if at all, even considered to be in "outer space" (and in some cases, possibly even lower than that). Such heights are almost negligible compared to the radius of Earth, which is why the horizon still appears mostly flat.

The problem for them is that we do have pictures of the curvature (even at low altitudes):

{{collapse|Views of Earth's curvature|width=500}}
<gallery>
File:First photo from space.jpg|First photo of Earth from space taken by the V-2 No. 13 rocket in 1946 at 65 miles. Despite the camera narrow field of view, Earth’s curvature is slightly visible.
File:Small Steps Panorama.jpg|First panoramic picture of Earth taken by the V-2 No. 13 rocket in 1947 from altitude greater than 100 miles in space.
File:Flying through the sunrise - Flickr - Lenny K Photography.jpg|Cabin window views of aircraft (roughly between 30,000 and 42,000 feet). A mild curvature is visible.
File:NASA's Global Precipitation Measurement Mission.jpg|Thunderstorms over South Carolina as observed from NASA’s ER-2 aircraft flying at 65,000 feet. A mild curvature can be seen.
File:Earth's Curvature at 29,394 metres.jpg|Panoramic picture of the Earth's curvature combining 18 images taken at 29,3 km (96.128 feet).
File:Picture taken at aprox. 100,000 feet above Oregon by Justin Hamel and Chris Thompson.jpg|Picture taken at approximately 30 km (100,000 feet) above Oregon using a {{wpl|weather balloon}}.
File:File RITCHIE-1 high-altitude balloon, Rochester Institute of Technology (5699591395).png|Photo taken from a high-altitude balloon at 53,5 km (33,2 miles) edited to correct fisheye lens distortion. The centre of the frame is indicated, where there is less distortion.
File:Armadillo Stiga rocket high altitude launch to nearspace (3.14).jpg| Armadillo Aerospace Stiga footage at nearly 140.000 feet (34,7 km) above sea level. 
File:High Altitude Balloon Flight - Over 117K Feet (line) 3.png|High-altitude balloon footage at 117.000 feet (35,6 km). The centre of the frame is indicated, where there is less distortion.
File:Barcelona, Spain - Flickr - NASA Goddard Photo and Video.jpg|Iberian Peninsula viewed at night from the International Space Station (ISS)
File:Aurora Borealis.jpg|Aurora Borealis over Quebec, Canada viewed from the ISS
File:Aurora Australis From ISS.JPG|Aurora Australis viewed from the ISS
File:STS115 Atlantis undock ISS edit2.jpg|Space Shuttle Atlantis viewed from the ISS
File:ISS with the Canadarm2.jpg|ISS viewed from Space Shuttle Endeavour
</gallery>
{{collapse end}}

And videos of it at different altitudes:

{{collapse|Videos showing Earth's curvature|width=500}}

All these are non-NASA, non-fish eye videos where the curvature is visible (and some are even from flat-earthers...):

* [https://www.youtube.com/watch?v=ZOsxgGeABGM Show me the Curvature... Here it is and don't blame the window - read comments before posting.] (13 km / 8 miles)  
* [https://www.youtube.com/watch?v=9DDwx18JT9Y The Horizon is not at Eye Level. Flying West over water with clear skies.] (14 km / 9 miles) 
* [https://www.youtube.com/watch?v=8OnJCqtTxsA James May Witnesses Curvature of Earth | James May: On The Moon | Earth Lab] (21 km / 13 miles) 
* [https://www.youtube.com/watch?v=ZUsBmlJI2f8&t=3700s Sending The Rock to Space! | Full Footage] (27 km / 17 miles) 
* [https://www.youtube.com/watch?v=dBBxMKe8yGg&t=6600s TestingTheGlobe's Second High-Altitude Balloon Launch] (30 km / 19 miles) 
* [https://www.youtube.com/watch?v=fvjFpZvG3U0&t=304s HIGH ALTITUDE BALLOON PROJECT] (31 km / 19 miles) 
* [https://youtu.be/tKC3kKpYZS0?t=171 Alpina AlpinerX Sent Into Space] (33 km / 20 miles)
* [https://www.youtube.com/watch?v=edsUrLXrlLg&ab_channel=FloPlus 100% proof of flat earth? Or is it? Dogcam high altitude balloon flight put to the test] (33 km / 20 miles)
* [https://youtu.be/MSksXKwGyjM?t=81 Sunrise high altitude balloon to the edge of space over Texas] (34 km / 21 miles)
* [https://www.youtube.com/watch?v=umAgH-0TOz4&t=5149s High Altitude Balloon 15 (Infrared Camera)] (35 km / 22 miles)
* [https://www.youtube.com/watch?v=G5kRyQStPhU&t=6721s High Altitude Balloon 18 (Infrared Camera)] (35 km / 22 miles)
* [https://www.youtube.com/watch?v=rvDqoxMUroA&t=178s Qu8k - BALLS 20 - Carmack Prize Attempt - High Altitude Rocket On-board Video] (37 km / 23 miles)
* [https://www.youtube.com/watch?v=y75lwIYc-CM High-altitude balloon flight to 38.5 km msl with a 2-axis gimbal] (38 km / 23 miles)
* [https://www.youtube.com/watch?v=hgSeDb-NbTw&t=7494s MAGE: Full uncut 127,000 feet / 38km high altitude balloon flight] (38 km / 24 miles) (38 km / 23 miles)
* [https://www.youtube.com/watch?v=dVOLj1je0lk&t=1200s MAGE II - What shape is the Earth?] (38 km / 24 miles)
* [https://www.youtube.com/watch?v=4QsEPEhq5yk&t=495s Above Earth - Successful Amateur Rocket Launch] (90 km / 56 miles)
* [https://www.youtube.com/watch?v=001IXnp0ogc GoFast Rocket Proves the Earth is Round?!] (117 km / 73 miles)
* [https://www.youtube.com/watch?v=o6r-Yf9J10o THE EARTH - FROM 76 MILES UP] (122 km / 76 miles) 
* [https://www.youtube.com/watch?v=y_RaS7P308k&t Watch Virgin Galactic VSS Unity's Full Flight! (Mission Recap)] 
* [https://www.youtube.com/watch?v=LTUeE9Y8EiY Watch Virgin Galactic soar to suborbital space for 5th time in amazing views] 
{{collapse end}}

Moreover, you don't always need to be at a high altitude to get footage showing the curve:

{{collapse|Earth's curvature view from Earth|width=500}}
Flat Earth debunker Bobby Shafto was able to photograph and measure the curvature of the horizon using a flat plank as a reference as Eric Dubay suggested.<ref>See his "proof" number 60.</ref> By magnifying the results vertically Shafto exaggerated the actual tiny curve present on the horizon in contrast with the planks, which remained flat. Since the horizon was in the center frame, the curve can't be the product of lens distortion.<ref>{{Cite web |date=2020-01-31 |title=Magnifying Images Vertically to Reveal Earth’s Curvature |url=https://flatearth.ws/vertical-magnification |access-date=2025-02-02 |website=FlatEarth.ws |language=en-US}}</ref>

{{video|youtube|KWUAuAvzxyc}}

Here's another example from [[https://www.metabunk.org/threads/how-to-take-a-photo-of-the-curve-of-the-horizon.8859/ Metabunk]]:

<gallery mode="packed">
File:How to Take a Photo of the Curve of the Horizon.JPG
File:How to Take a Photo of the Curve of the Horizon1.jpg
</gallery>

This same effect can be done even in commercial aeroplanes.

<gallery mode="packed">
File:HudsonBay3k.jpg
File:HudsonBay3-g.jpg
</gallery>

More examples [https://imgur.com/a/psWVVC1 here].

{{collapse end}}

However when ''we'' provide pictures of a ''curved'' horizon, they [[Special pleading|make unfounded claims like that the gear used to take the picture warps the horizon, causing it to look curved]]. And since space agencies take most pictures from space they can't be trusted. Throwing their logic right back in their face by claiming that ''their'' pictures are the faked ones typically results in — as when this is done to any conspiracy theorist — [https://www.youtube.com/watch?v=mKkLjJHwRec| the old Windows error ding] emanating from their cranium.

==="But fish eye lenses curve the horizon!"===

Wide-angle or "fish eye" lens cameras (like GoPros) allow to capture a large field of view footage but suffer from huge {{wpl|barrel distortion}}. This distortion can and does bend straight edges and flat surfaces, which would give the illusion of the Earth’s horizon on high altitude videos appearing “curved”, thus making the perfect flat Earth excuse. What flatties conveniently ignore is that these distortions are particularly noticeable near the edges of the frame but the centre of the frame generally remains the least distorted. This means that the horizon at the centre frame would appear straight if the Earth were flat. ''Spoiler alert!'' It doesn't...<ref>[https://flatearth.ws/high-altitude-balloon Curvature of the Horizon in High-Altitude Balloon Footage] Flatearth.ws</ref>

<gallery>
File:RITCHIE-1 high-altitude balloon, Rochester Institute of Technology (5699593195).jpg|Horizon above centre frame.
File:RITCHIE-1 high-altitude balloon, Rochester Institute of Technology (5699594535).jpg|Horizon below centre frame.
File RITCHIE-1 high-altitude balloon, Rochester Institute of Technology (5699591395).png|Horizon at centre frame (where no distortion is present).
</gallery>


[[File:ExplorerII-Stevens-Anderson-Balloon-image.jpg|thumbnail|right|300px]]

The first photograph that shows the curve (see the image on the right), was taken by {{wpl|Albert_William_Stevens|Albert William Stevens}} and {{wpl|Orvil_A._Anderson|Orvil A. Anderson}} from the {{wpl|Explorer_II|Explorer II|}} high altitude balloon, at the altitude of 72,395 ft (22.066 km), on November 11, 1935. The film magazine cover in the [https://airandspace.si.edu/multimedia-gallery/explorer-II-panojpg panorama photo] from Explorer II matches that of the [https://www.asprs.org/wp-content/uploads/1944_sep_136-159.pdf#page=2 Fairchild K-3A aerial camera] , which [https://airandspace.si.edu/collection-objects/camera-aerial-fairchild-k-3a-us-navy/nasm_A19710957000 has] an Eastman Kodak Aerostigmat 12" (305mm) f-5.0 lens. As per [https://opg.optica.org/josa/abstract.cfm?uri=josa-37-1-1 this] paper, the lens is a {{wpl|Tessar|Tessar}} lens which is an {{wpl|Anastigmat#Later_development|anastigmatic lens|,}} which means, like Wikipedia states, that it is completely corrected in the three main main {{wpl|Optical_aberration|optical aberrations}}: {{wpl|Spherical_aberration|spherical aberration|,}} {{wpl|Coma_(optics)|coma|,}} and {{wpl|Astigmatism_(optical_systems)|astigmatism|.}} In other words it has no distortion. Michael Toon has a high resolution scan of the photo [https://mctoon.net/wp-content/uploads/2022/12/1935-sdakota.pdf here] and an article [https://mctoon.net/first-curve/ here]. As can be seen from the black horizontal line, the curve is obviously there.

=== "So why is distant object X visible when it shouldn't be?" ===

[[File:Toronto skyline.jpg|right|thumb|The skyline of Toronto...
[[File:Comparison of Chicago being hidden by Earth's curvature2.gif||295px|center]]
...and the skyline of Chicago are often cited by flat-earthers because, apparently, they can be seen from miles away. The fact that half of the cities are underwater is, apparently, lost on them.<ref>[https://flatearth.ws/toronto Toronto] ''FlatEarth.ws''.</ref>]]

According to Flat-earthers, there are distant objects (like buildings or mountains) that shouldn't be visible because they would be hidden under the horizon due to the curvature,<ref>Of course, on a flat Earth even Mount Everest should be visible from any location (needless to say, it isn't).</ref> yet they are (some of them party visible, like half of it under the horizon... We wonder why). 

Perhaps this might be the best shot flat-earthers have used to disprove a globe.  Unfortunately, since these are verifiable claims, they can be examined and always fall apart because they often either fail to use the correct formula or miss important factors in their "calculations".

{{collapse|Curvature drop formulas|width=900}}
[[File:Measurement of Horizon Drop comparing use of Pythagorean Theorem to 8 in per mile squared "rule".jpg|200px|thumb|right|Comparison of the horizon's drop between the Pythagorean Theorem and the 8" per mile squared "rule" shows the latter is off by 21% at 3,960 miles, and thus, inherently inaccurate.]]
[[File:Hidden height and curvature drop.jpg|thumb|right|200px|Flat-earther M. Kahnke's 2015 "proof" of curvature for a ball with a radius of 3,959 miles. This chart, while technically not entirely inaccurate, is often abused by flat-earthers to calculate the expected amount of obstruction when it is unsuitable for such purposes. It does not take into account the observer's height, or the atmospheric refraction.<ref>{{Cite web |date=2018-10-18 |title=Earth’s Curvature Calculation |url=https://flatearth.ws/curvature-calculation |access-date=2023-01-06 |website=FlatEarth.ws |language=en-US}}</ref> It also fails to show the effect of an object's hidden height, i.e. how tall it should be to be visible at '''L=0'''. Objects in color have been added to illustrate the point.]]

'''Approximated curvature drop formula (8" per mile squared)'''

This is the most common formula flat-earthers use. Eric Dubay has [https://youtu.be/WmqE2cRFbPU?si=5zFEobl5iM_oujRO&t=386 lied] this formula has been provided by globe earthers as something that "''represents reality''". In the actual reality, this formula is copy-pasted from Rowbotham's ''Zetetic Astronomy'' [https://archive.org/details/1865RowbothamZeteticAstronomy/page/8/mode/2up page 8, lines 7-10].

The formula is [https://www.youtube.com/watch?v=6SuPLe7j9Ys derived] from the Pythagorean approximation of

::[[File:Approximated curvature drop formula.svg|100px]], where
<!-- <math>\text{drop} \approx \frac{d^2}{2 \cdot R}</math> -->

* '''d''' is the distance from observer and
* '''R''' is the radius of Earth,

by taking a tangent line of 1 mile on a circle of radius 3963 miles. The drop would be about 0.000126 miles or 7.98 inches.<ref>https://mathcentral.uregina.ca/qq/database/qq.09.97/dyck2.html</ref>

'''Why it's wrong:''' Rowbotham's formula describes a parabola, not a circular surface. Thus, it has an error of less than 1% only up until 800 miles.<ref>[https://www.online-python.com/bWDGRL2XYQ "Comparison of Rowbotham's formula and the correct formula"]. Via online-python.com</ref> 

<br>

'''The true curvature drop formula''' 

This formula, used e.g. by  [https://earthcurvature.com Eldøy Projects' Earth Curvature Calculator], is


::[[File:True curvature drop formula.svg|175px]], where 
<!-- <math>\text{drop} = r \cdot (1 - \cos \theta)</math> -->

* '''θ''' is the arc angle of the distance (0.009° * (d)) and 
* '''r''' is Earth's radius. 

'''Why it's wrong:''' First, because it's often misused. It only describes how much the Earth's surface shifts relative to the direction a plumb line points at the observation point. Due to Earth's curvature, vertical objects tilt away more as distance to the object increases. An object pointing e.g. 45° away from us, would need to be '''√2 ≈ 1.42''' times taller than the value this formula provides, to be visible. This part that's not visible, is called the '''hidden height'''. And second, more importantly, it ignores the '''observer's height'''.


'''Simple hidden height formula''' 

A simple hidden height formula used in [https://www.omnicalculator.com/physics/earth-curvature omnicalculator.com] that takes into account the observer's height is:

::[[File:Simple hidden height formula.svg|180px]], where 
<!-- <math>\text{drop} = \sqrt{(r+h)^2 - r^2}</math> -->

* '''h''' is the observer's height at sea level, and 
* '''r''' is Earth's radius. 

'''Why it's wrong:''' It doesn't take into account {{wpl|Atmospheric_refraction|atmospheric refraction|.}}


'''Comparison'''

With this in mind, let's do a comparison of these three formulas. At a literal altitude of sea level (that is literally 0 feet) we should have at 10 miles:

{| class="wikitable"
! Formula !! Hidden Height (mi) !! Hidden Height (ft)
|-
| 8" per mile squared || 0.01262 || 66.67
|-
| Eldøy Projects || 0.01263 || 66.690
|-
| omnicalculator.com || 0.0126302 || 66.688
|}

As you can see, these formulas get very similar results. However, we don't live lying down on the ground at the beach. So we need to assume some observer's height—higher than 0 at least. If we take into account 100 feet for the observer's altitude, then, according to "omnicalculator.com," the hidden height is now 0 because anything at 10 miles is visible since the horizon should be 12.25 miles away.

{{collapse end}}

The most crucial factor that flat-earthers often ignore is the '''observer's height''', which makes a huge difference. The higher you are the further you see. This is the reason why ancient sailors climbed the masts of a ship to see boats and lighthouses in the distance, or why the Sun sets later the higher you are (two phenomena that flat-earthers can't explain). 

Sometimes flat-earthers do take the observer's height into account and still use this point. This is, of course, a form of a desperate "[[black swan]]" case argument, "an exception to the rule" (the fact that this is exception and not the rule pretty much suggests a flat Earth is non-sense), which ultimately fails because ''*surprise surprise*'' there is another big factor they missed... (*drumroll*): '''{{wpl|Atmospheric refraction}}''', which can make light rays curve with a radius seven times the Earth's surface. This happens when light hits a pocket of cold air or a hot draft of rising air, bending the light from the object that would usually hit the ground, going around the Earth's surface and reaching to the observer's eye.<ref>{{Cite web |title=Distance to the Horizon |url=https://aty.sdsu.edu/explain/atmos_refr/horizon.html |access-date=2023-05-10 |website=aty.sdsu.edu}}</ref> These cases can be easily distinguished because they look incredibly distorted.<ref>{{Cite web |date=2020-03-11 |title=Distance to the Horizon & the Black Swan Observation |url=https://flatearth.ws/horizon-distance |access-date=2023-01-07 |website=FlatEarth.ws |language=en-US}}</ref><ref>{{Cite web |title=Simulation of Atmospheric Refraction |url=http://walter.bislins.ch/bloge/index.asp?page=Simulation+of+Atmospheric+Refraction |access-date=2023-05-10 |website=walter.bislins.ch |language=de}}</ref> 

[[File:Distance record2.jpg|thumb|right|One example flat-earthers use is the current [https://www.guinnessworldrecords.com/world-records/66661-longest-line-of-sight-on-earth longest line of sight photograph record]. The photo of Pic Gaspard by Mark Bret from July 16, 2016.<ref>Bret, Mark (August 3, 2016). [https://beyondrange.wordpress.com/2016/08/03/pic-de-finestrelles-pic-gaspard-ecrins-443-km/ "443 KM | Finestrelles, Pyrenees – Pic Gaspard, Alps"] Via beyondrange.wordpress.com</ref> Flat-earthers like [https://youtu.be/a7pd-TH-grI?si=pKp4e3jD3nHH3Qtf&t=2007 Eric Dubay] have claimed this distance is not possible, because the Earth's curvature comes in the way. While technically true, what they don't disclose, is the author specializes in photography that intentionally waits for perfect refractive conditions to make such photos possible.<ref>Bret, Mark. [https://beyondrange.wordpress.com/visibility-facts/refraction/ "Visibility facts - Refraction"] Via beyondrange.wordpress.com.</ref>]]

{{collapse|Flat Earth "Black Swan" example |width=900}}
<gallery mode="packed" heights="200">
File:Blackswan1.webp ‎ | (Picture 1) Flat Earth "Black Swam" meme.
File:Blackswan2.webp ‎ | (Picture 2) Same oil rigs on a clearer day.
</gallery>

The photo of the oil platforms (Picture 1) is the most popular example of the "[[black swan]]" argument that flat-earthers use.<ref>{{Cite web |date=2020-03-11 |title=Distance to the Horizon & the Black Swan Observation |url=https://flatearth.ws/horizon-distance |access-date=2025-01-19 |website=FlatEarth.ws |language=en-US}}</ref> In a nutshell: There are two oil rigs at 9.41 miles and 6.21 miles away ([https://earth.google.com/web/search/platform+habitat/@34.36414025,-119.57707901,-2.8653719a,18228.96903339d,35y,-179.368111h,57.97820129t,0.00000084r/data=CiwiJgokCV4A4eu8JkFAER-YzUO2IkFAGbax_F_R413AIYJ3TQYJ6F3AQgIIAUICCABKDQj___________8BEAA map]), but the horizon appears behind both rigs. This picture was taken at an altitude of 1 feet. According to the calculations from above, the distance to the horizon should have been 2.72 miles, and the oil platforms shouldn't be completely visible. ''Conclusion: Earth ain't ball. Checkmate globers!''

First, two glaring problems that even [[Answers in Genesis]] have noticed (yeah... AiG... we kid you not)<ref name=":blackswan">[[Answers in Genesis]]. (February 5, 2021) [https://answersingenesis.org/blogs/danny-faulkner/2021/02/05/black-swan-evidence-earth-flat/?srsltid=AfmBOoqjYo1_zS5b85qRmk0ugjLdrnKpQEGnZ79_yNszY6DE52MKECWV The Black Swan: Evidence the Earth Is Flat?]</ref> are that: 

# If we took the flat Earth mantra of "trusting our senses" then we can see that oil rig on the left looks... to put it bluntly... ''VERY FUCKED UP!'' Just look at those ''incredibly distorted'' and ''crooked cranes'' on the platform! Not to mention how blurry the picture is in general. On a clearer day, we can see how these oil rigs actually look like (Picture 2). Unsurprisingly, is what the spherical Earth predicts.
# The existence of "black swans", no matter how many they are, doesn't disprove the overwhelming majority of "white swans". As noticed before, this "black swan" phenomenon on a flat Earth wouldn't be the exception but the rule. The fact that even the original flat-Earther who took both pictures admitted<ref name=":blackswan"/> that (Picture 2) is more common than (Picture 1) doesn't help their case.

Now, getting more technical. The photo (Picture 1) is clearly an extreme example of atmospheric refraction. Contrary to flat Earth opinion, this is nothing but a "black swan" in modern physics but a well-understood phenomenon since the times of Gauss and beyond. As mentioned above, air refraction can bend the light of distant objects, making them go around the horizon and reach further than normal conditions. Mick West<ref>{{Cite web |date=2020-03-08 |title=Flat Earth and Refraction with Oil Platforms Hillhouse and Habitat |url=https://www.metabunk.org/threads/flat-earth-and-refraction-with-oil-platforms-hillhouse-and-habitat.11137/ |access-date=2025-01-19 |website=Metabunk |language=en-US}}</ref> and Walter Bislin<ref>{{Cite web |title=Strong Refraction Simulation and Reality for 2 Oil Platforms |url=https://walter.bislins.ch/bloge/index.asp?page=Strong+Refraction+Simulation+and+Reality+for+2+Oil+Platforms |archive-url=http://web.archive.org/web/20240518040443/https://walter.bislins.ch/bloge/index.asp?page=Strong+Refraction+Simulation+and+Reality+for+2+Oil+Platforms |archive-date=2024-05-18 |access-date=2025-01-19 |website=walter.bislins.ch |language=de}}</ref> have taken this important factor into account in more sophisticated calculations for their simulations. In this case, as Walter explains, in (Picture 1) there is "temperature inversion", a layer of cool air between warmer air which increases the refraction coefficient (k). "This is the cause of the different strechings and compressions and the waves in straight structures like the cranes. A positive temperature gradient above the ground (cool ground, warm air above) causes additional {{wpl|looming}}. This is the reason why no distinct horizon is visible".

In a spectacular Shyamalan's plot twist style, some flat-Earthers have claimed that it is actually (Picture 2) the refracted picture! Why? ''Because the oil rigs are under the horizon! And we can't trust our senses for that''... Ignoring this ''brilliant'' excuse, flat-Earthers have tried to invent new fancy physics to explain that picture (like "atmospheric magnification") but never test it. However, Mick and Walter have tested and shown in their simulations that for (Picture 2) to happen on a flat Earth due to refraction there must be a negative temperature gradient of "−15°C per 100 m throughout the whole atmosphere", which "is physically impossible" (especially on a sunny day like in the picture).

One final nail in this black swan coffin: Bob the Science Guy has also shown that even in (Picture 1) about 15 feet are missing for the left oil rig and 5.5 feet for the right oil rig, which is expected on a spherical Earth.<ref>{{Cite AV media |url=https://www.youtube.com/watch?v=n6jFUBBMYi4&ab_channel=BobtheScienceGuy |title=Final Analysis of the Black Swan   Still a GLOBE |date=2022-03-02 |last=Bob the Science Guy |access-date=2025-01-19 |via=YouTube}}</ref><ref>See also BlueMarbleScience. [https://www.youtube.com/watch?v=WArmXPb8HwI&ab_channel=BlueMarbleScience Sleeping Warrior Still Can't Science!]</ref>

''RIP flat Earth "Black Swan"''
{{collapse end}}
<u>'''''TLDR;'''''</u> most flat-earthers' examples:
* Use '''wrong distances''',
* Forget the '''observer's height''',
* Ignore the effects of '''atmospheric refraction''',
* [[Cherry_picking|Cherry-pick]] footage,
* Confuse the distant objects for others (like mountains for clouds... seriously),<ref>https://www.youtube.com/watch?v=AAQd9DVfoSQ&ab_channel=SciManDan</ref> or
* Have no way to verify the information for their picture evidence (and sometimes there isn't even a picture, just a ''trust me bro'').

In the end, debunking every example flatties can throw at you can feel like a ''whack a mole'' game. When one "calculation" is disproven, two more appear (see [[Gish Gallop]]). This process can be very exhausting. So, if you happen to be arguing with some flattie right now, we highly recommend you [http://walter.bislins.ch/bloge/index.asp?page=Finding+the+curvature+of+the+Earth Walter Bislin's online curvature simulator], which accounts for all these factors (eg. target inclination, observer's height and atmospheric refraction). See below for the formula it uses:

{{collapse|The correct hidden height formula|width=900}}

'''The correct hidden height formula'''

The last thing that's missing from the formulas above is, as we already said, the atmospheric refraction. According to [https://flatearth.ws/hidden-formula#more-5946 FlatEarth.ws], this is accounted for in the following Walter Bislin's formulas:

If the distance along Earth's surface is known:

::[[File:Correct hidden height formula known distance along earths surface.svg|280px]]
<!-- <math>h_h = \frac{R}{\cos[\frac{s}{R}-\arccos(\frac{R}{R+h_o})]}-R</math> -->

If the line of sight distance is known:

::[[File:Correct hidden height formula known los distance.svg|350px]]
<!-- <math>h_h = \sqrt{ \left[d-\sqrt{(R+h_o)^2-R^2} \right]^2 + R^2-R }</math> -->

where 
* '''hₕ''' = is hidden height
* '''d''' = line of sight distance between observer and object
* '''s''' = distance between observer and object along Earth's surface
* '''hₒ''' = height of the object from Earth's surface
* [[File:Correct hidden height formula r.svg|260px]]

<!-- <math>R = \frac{\text{Earth's radius without refraction}}{\text{Refraction coefficient*}}</math> -->

\*The {{wpl|Refractive index|refraction coefficient}} depends on the atmospheric condition, which commonly is around between 0.13 and 0.17.

{{collapse end}}
''Use this weapon wisely''.

=== "So why isn't distant object X leaning away from us?" ===
The further a distant object, like a building, is away from us, the more it leans due to Earth's curvature. However, as it has been mentioned before, the Earth is REALLY BIG and flat-earthers can't understand scales. That's why many of them think any distant building should look like the Leaning Tower of Pisa. In reality, for any object to be tilted just ONE DEGREE by the curvature of Earth, it should be around 69 MILES away ([[Sex|*''nice''*]]). For an example of the math, see Dan Olson [https://youtu.be/JTfhYyTuT44?feature=shared&t=822 debunk Alaska's leaning Mt. McKinley].

==="So why did Neil deGrasse Tyson say ''"stuff is flat"'' regarding Red Bull Stratos?"===
Yes, [[Neil deGrasse Tyson]] said in regards to {{wpl|Felix Baumgartner}}'s {{wpl|Red Bull Stratos}} jump that: "''At that height, you don't see, you don't see the curvature of the Earth [...]. You just don't. That stuff is flat!''". He pointed to a 20" inflatable beach ball that Felix Baumgartner would have been about 2mm above the surface of this globe.

In reality, Tyson was wrong. A curvature would still be visible at 38.9694 kilometres (24.2145 mi). To be fair, the curve wouldn't be very big, but it would still be there. And there are even pictures of it, and Felix himself has gone on record declaring he saw Earth's curvature.<ref>{{Cite AV media |url=https://www.youtube.com/watch?v=fWjweUbR99U&list=PLWBhBecDGXhkH6qPbVQkjUftpGEMkVvXS&index=133&ab_channel=Wade%E2%80%99sUnderworld |title=Felix says he saw the CURVATURE of the EARTH during red bull space jump |date=2021-05-08 |last=Wade’s Underworld |access-date=2025-02-02 |via=YouTube}}</ref><ref>{{Cite news |last=Baumgartner |first=Felix |date=2012-12-23 |title=Felix Baumgartner on falling from space |url=https://www.theguardian.com/sport/2012/dec/23/felix-baumgartner-falling-from-space |access-date=2025-02-02 |work=The Guardian |language=en-GB |issn=0261-3077 |quote=How many people have had the opportunity to see the curvature of the Earth below and a completely black sky above?}}</ref> In other words, the fact that Neil was wrong doesn't help your case flatties. It's ironic that they now trust Neil's words and not Felix's, right?

The most common reply from flat-earthers like [[Eric Dubay]] is that in the Red Bull Stratos jump GoPro cameras with fish eye lenses were used, thus distorting the horizon. Instead, we should look at the camera inside the cabin, where moments before Felix jumped the horizon was visibly flat when he opened the shuttle door. Firstly, while it is true Red Bull used GoPro cameras, flat-earthers forget this footage can be easily corrected with editing software. According to [https://www.metabunk.org/threads/debunked-neil-degrasse-tyson-that-stuff-is-flat.10723/ this] metabunk article, the camera was the Canon 5D Mark II or Mark III, and the lens was a Canon 15mm f/2.8 fisheye. They applied the correction and guess what, the curvature is still there. Granted, it is very very very small, but it's still there. Flat-earthers sometimes try to cheat by [[Circular reasoning|"correcting" the footage until the horizon looks flat]] instead of adjusting for the camera settings. The problem for them is that now everything but the horizon is distorted.<ref>https://flatearth.ws/felix-baumgartner#more-3668</ref>
<gallery>
File:Gopro-released-new-hd-footage-of-felix-baumgartners-space-jump-its-insane.webp|Red Bull's picture of Felix Baumgartner's before the jump.
File:Baumgartner real jump corrected.jpg|Red Bull's picture corrected (defished).
File:Metabunk 2019-05-15 14-58-18.jpg|Close up of the mild curvature.
</gallery>
Secondly, Dubay is basically cheating, again, expecting to see the Earth's curvature in the shuttle door because it is literally cropped by it. Unfortunately for Dubay, there was also a window next to the door shuttle and if we look the horizon in both the window and the shuttle, a tiny curve is visible. A tiny one, but a curve anyway.
<gallery>
File:Felix Baumgartners sonic boom captured from the ground.jpg|Red Bull's picture of Felix Baumgartner's opening the door shuttle.
File:Felix says he saw the CURVATURE of the EARTH during red bull space jump.jpg|Hightlights of the horizon in the window and door. It's not flat.
</gallery>

==="But ''globers'' claim you both can and can't see the curvature!"===

A typical flerf "[[gotcha argument]]" is claiming that it is contradictory to hold both:
#Earth is '''too big''' for us '''to see''' the ''curvature'', but
#We '''can see ships''' go over the ''curvature''. 
Of course, there's no contradiction between these two statements, just an [[equivocation]] fallacy<ref group=note>In the first statement the word "curvature" refers to the curvature '''of the horizon''' due to Earth's spherical shape, while the second refers to an effect of Earth's curve surface (no matter how much ad hoc explanations flerfs have for it). These claims can be easily restated to avoid misunderstandings as follows:
#Earth is '''too big''' for us '''to see''' its ''curvature'' '''''on the horizon''''', but
#We can '''can see ships''' go over the horizon due to ''curvature'' '''''of Earth's surface'''''.</ref> and a misunderstanding between direct and indirect observations<ref group=note>Just like we can confirm the presence of bears in a forest just by either directly observing them or noticing trails pointing to them (like footprints), we can also prove the curved surface of Earth by directly observing it or watching its effects on the ground that can only be reasonable be explained by it (like ships going under the horizon). Of course, flat-earthers have ''ad hoc'' explanations to fit those observations just as much those footprints actually fit to [[Bigfoot]] instead.</ref> (see also the creationist ''[[How do you know? Were you there?]]'' argument).

Really, the fact that there even '''is''' a horizon to begin with should prove the Earth to be round by itself, since on a flat Earth there wouldn't be a distinct line of sight dividing the sky from the ground (or sea for that matter).

==="But the radio waves can travel too far!"===

[[File:Chatgpt2.jpg|thumb|right|Free version of ChatGPT has zero issues pointing out methods for communicating behind horizon, when prompted.]]

In his Feb. 5, 2025 [https://youtu.be/NFDevyQrfg8?feature=shared&t=204 crank video] Eric Dubay discussed {{wpl|Guglielmo_Marconi|Guglielmo Marconi's}} Sept. 1930 radio transmission from {{wpl|Poldhu|Poldhu, UK|,}} to Sydney, Australia. Dubay claimed high transmission power and sophisticated antennas alone, allowed radio signals to travel the 12,000 mile distance.<ref group=note>Dubay doesn't check his facts, it's actually 10,800 miles.</ref> Dubay then turned his crankery to 11 and spouted this insanity: 

{{cquote|Using the official Earth curve calculator, the calculation determined that based on a spherical Earth model, the receiving antenna in Australia would have to be approximately 7,893 miles below the horizon. This prompted me to investigate the feasibility of such an extremely distant radio transmission scenario using an AI Chatbot, based on a spherical Earth model.

'''Question:''' Can you envision a scenario where radio signal could be transmitted and received successfully, despite being 7,893 miles below the spherical Earth's horizon?
'''Answer:''' The concept of a radio signal traveling 7,893 miles below the horizon of the spherical Earth, is far beyond the capabilities of radio signal transmission for this distance. The curvature of the Earth poses a physical limitation on the direct line of sight for radio signals. As the Earth curves, objects or signals beyond the horizon are not visible or receivable due to the obstructed view. While techniques like antenna height, signal amplification, and atmospheric conditions can extend the range of radio signals to some extent, they can not overcome the fundamental limitation imposed by the Earth's curvature, especially at distances this remote.|||Eric Dubay<ref>Dubay, Eric (Feb. 5, 2025). [https://youtu.be/NFDevyQrfg8?feature=shared&t=270 "5 Real-World Flat-Earth Proofs"]. Via youtube.com.</ref>}}

Dubay provided no evidence his language model had even produced the answer. However, as explained by page 15 of [https://www.researchgate.net/publication/371503465_MARCONI'S_FIRST_TRANSATLANTIC_WIRELESS_TRANSMISSION_Figure_1_George_Kemp_with_a_Baden-Powell_kite this paper],

{{cquote|In 1923, the state of the art Marconi super-station in Australia broadcast on ultra long wavelength, from 20 steel masts, each 244 metres (800ft) high, and 1000kW power output. A year later, Marconi sent transatlantic transmissions from Poldhu to New York using a short wave of 37 metres and just 17kW of power. '''Short waves, it turns out, are reflected remarkably well by the ionosphere.'''}}

Dubay is basically lying his ass off, and at the same time, shifting blame to a language model for getting it wrong, if he even used one. This is why academics never rely on language models when checking facts.

The technique of bouncing radio signals off the ionosphere is called a {{wpl|Skywave|skywave (or, skip)|,}} and it's been used since the 1920s. Also, having reserached Marconi, Dubay should have learned, that {{wpl|Skywave#Marconi|Marconi was the first to show radios could communicate beyond the curve|.}}

===Mountains cast shadows to clouds only on a globe===

[[File:Mt rainier.jpg|thumb|right|Rising Sun casts Mt. Rainier's shadow to clouds, proving the Earth a globe.]]

A photo taken by Reddit user PCloadletter26, shows a sunrise, that casts {{wpl|Mount_Rainier|Mount Rainier's}} shadow to the clouds. If the Earth was flat, the Sun would never be below the tip of the mountain.

In his [https://youtu.be/J7RwAcL4Iq0?si=HKiRIp0uwP2yJYE5&t=9814 rant], Eric Dubay tries to claim the that the sunlight was reflected from the Earth's surface to clouds. The photo is taken from [https://earth.google.com/web/search/47%c2%b014%2751%22N+122%c2%b026%2707%22W/@47.24509464,-122.43103586,24.61433156a,500.2240021d,35y,132.32887408h,86.49080502t,0r/data=CmAaMhIsGUfhehSun0dAITDrapfbm17AKhg0N8KwMTQnNTEiTiAxMjLCsDI2JzA3IlcYASABIiYKJAlxlJLL459HQBEUSxmDY59HQBlXmk6go5tewCGuoYtOAJxewEICCAFCAggASg0I____________ARAA 47°14'51"N 122°26'07"W]. This begs the question, what is causing the specular reflections? The nearest body of water due East, is Lake Michigan at 1700 miles (2,700 km).

In [https://youtu.be/J7RwAcL4Iq0?si=R3I1OCmS4LyQTDtU&t=9937 one illustration (bottom left)] Dubay tried to claim that the shadow could be drawn to the clouds by a Sun that's above the mountaintop. This makes no sense, as in that case the Sun would just light the cloud. The shadow would only be cast to the ground. The light behind the mountain does not hit the mountain before it transits through the cloud so there won't be a shadow in those clouds either. Dubay then constructed a massive strawman about sunrise casting a growing upside down shadow that doesn't break shape as the Sun gets higher. This is bullshit of course, as seen in the video below:

{{collapse|Mount Rainier sunrise|width=500}}
<center>{{#ev:youtube|https://www.youtube.com/watch?v=0q4luTQyiSk|||||start=0}}</center>
{{collapse end}}

==Shape==

==="So why did Neil deGrasse Tyson say the Earth was ''pear shaped''?"===
[[File:Himawari 8 True Colour 2016-02-10 0320Z (cropped).jpg|thumb|right|200px|Earth photo from {{wpl|Himawari 8}} (2016-02-10). Although it looks like a perfect circle it's actually nine pixels wider.]]

[[File:Geoid undulation 10k scale.jpg|thumb|right|200px|Computer representation of Earth's geoid shape with vertical exaggeration (10000 scale factor). This is what Tyson refered with [https://en.wikipedia.org/wiki/Figure_of_the_Earth#Pear_shape "pear shaped"].]]
This [[argument from authority]] is used often by flat-earthers to claim that the scientific community is lying. [[Neil deGrasse Tyson]] has been [[Quote mining|quoted]] saying, "''Earth is not only oblate — wider at the equator than pole-to-pole, but pear shaped — slightly wider just south of the equator.''"<ref>"[https://twitter.com/neiltyson/status/512994844801638400?lang=en Neil deGrasse Tyson on Twitter]". ''Twitter''.</ref>

But in reality, Tyson was describing the fact that just as the Earth is technically not an exact sphere, it is also not technically an exact oblate spheroid either. As the ''Universal Cyclopaedia'' (1894) put it:
{{cquote|As the surface of the Earth is rugose, and as the bodies of rock immediately beneath the surface vary in density, and therefore in attraction, the level surface has local irregularities, undulating gently in every part. When account is taken of these undulations the level surface is called a '''geoid''', to distinguish it from the '''ideal terrestrial spheroid''' to which it approximates.<ref name=":Cyclopaedia"/>}}

The '''figure of the Earth theory''' has considered the Earth to be globular since antiquity. Over time, as surveying equipment has developed, more accurate models have been introduced.
* The '''{{wpl|Spherical Earth}}''', i.e., perfect sphere model, has existed since the time of Pythagoras, 600 BCE. It's useful for most purposes, as it allows making rough estimates with simple calculations. Even today, it is suitable for school-level physics, and for explaining e.g. the concepts of latitude and longitude, without boring into unnecessary detail.
* The '''{{wpl|Oblate_spheroid|Oblate spheroid}}''' model, i.e. squashed sphere, has been around since Isaac Newton's 1687 {{wpl|Philosophiæ_Naturalis_Principia_Mathematica|Principia|.}} It accounts for Earth's spin having caused a 0.33%<ref>"[https://www.quora.com/If-the-Earth-is-a-oblate-spheroid-why-isnt-this-evident-in-NASA-images-from-space If the Earth is a oblate spheroid why isn't this evident in NASA images from space?]". ''Quora''.</ref> bulge at the equator during the {{wpl|Hadean|Hadean era|.}} Since the difference is extremely small, it's no wonder Earth appears as perfectly spherical in most photos.<ref>Charles Q. Choi (12 April 2007). "[https://www.scientificamerican.com/article/earth-is-not-round/ Strange but True: Earth Is Not Round]". ''[[Scientific American]]''.</ref> Just for scaling, if we could grab the entire Earth with our hand it'd be as ''round'' as a billiard ball (although not a good one).<ref>Abrahams, Marc (April 3. 2012). [https://improbable.com/2012/04/03/billiard-balls-versus-the-earth/ Billiard balls versus the earth]. Via improbable.com</ref> Oblate spheroid is a generic term, however. The one representing the Earth is called the {{wpl|Earth_ellipsoid#Reference_ellipsoid|reference ellipsoid|.}} The reference ellipsoid is used in {{wpl|Geodesy|geodesy|,}} and {{wpl|Cartography|cartography|.}} Even the reference ellipsoid has improved over time. In fact, there have been at least {{wpl|Earth_ellipsoid#Historical_Earth_ellipsoids|24 different reference ellipsoids|}} between 1738 and 2003.
* The '''{{wpl|Geoid|Geoid}}''' model was first introduced in 1828,<ref>National Geodetic Survey. [https://www.ngs.noaa.gov/GEOID/geoid_def.html "What is the geoid? Early history"] Via noaa.gov.</ref> and by 1957, The Columbus geoid<ref>[https://www.researchgate.net/figure/The-Columbus-geoid-Heiskanen-1957_fig2_332461814 "The Columbus geoid (Heiskanen, 1957)"]</ref> was already pretty close to the modern {{wpl|Earth_Gravitational_Model#EGM2008|EGM2008}} model. The geoid model also includes the hills, mountains, and the shape of the seabed, and it is used, e.g., for modern GPS<ref>Global GPS Systems [https://globalgpssystems.com/gnss/geoids-ellipsoids-and-undulation-height-understanding-the-basics/ "Geoids, Ellipsoids, and Undulation Height: Understanding the Basics"]. Via globalgpssystems.com</ref> and when searching for oil deposits, as it doesn't ignore gravitational anomalies.<ref>[http://www.ogj.com/articles/print/vol-110/issue-11/special-report-applied-geophysics/detailed-gravity-magnetics-successful.html Detailed gravity, magnetics successful in exploring Azerbaijan onshore areas. ''Oil and Gas Journal'']</ref>
:'''The pear shape:''' As {{wpl|Figure_of_the_Earth#Pear_shape|Wikipedia}} explains, "''The theory of a slightly pear-shaped Earth arose when data was received from the U.S.'s artificial satellite Vanguard 1 in 1958. It was found to vary in its long periodic orbit, with the Southern Hemisphere exhibiting higher gravitational attraction than the Northern Hemisphere.''" As the original paper<ref>{{cite journal |last1= O’Keefe |first1=J. A. |last2=Eckeis |first2=J.A. |last3=Squires |first3=R.K. | |date=1959 |title=Vanguard Measurements Give Pear-Shaped Component of Earth’s Figure |journal=Science |volume=129 |issue=3348 |pages=565-566 |doi=10.1126/science.129.3348.565}}</ref> on Vanguard 1's findings states: "''Our calculations indicate that the periodic changes in eccentricity can be explained by the presence of a third zonal harmonic in the earth's gravitational field. The third zonal harmonic '''modifies the geoid toward the shape of a pear. In the present case, the stem of the pear is up-that is, at the North Pole.'''''"

So, again, the '''figure of the Earth theory''' has ruled out flat Earth as a model more than 2,500 years ago. Since then, the globular model has slowly improved to account for more specialized use cases. Again, all models are wrong, but some models are useful. Simpler models are more wrong, but still useful for some basic tasks, and for young learners who are building their knowledge from scratch.

By describing Earth as having a pear-like shape, Tyson communicated the almost imperceptible nuances of the shape, compared to oblate spheroid, with a relatable concept. He also accurately used the same example as the original scientific paper. He could have said "''Its shape is described by EGM2008, a gravitational model complete to spherical harmonic degree and order 2159, with additional coefficients extending to degree 2190 and order 2159.''" and alienated half of his readers, but as a {{wpl|Science_communication|science communicator|,}} his job is the opposite of that.

==Gravity==

==="Gravity does not exist!"===
Yes, flat-earthers are gravity deniers, and for a good reason: it would make their world collapse into a sphere and the trajectory of falling objects would become increasingly tilted inwards in the "Southern latitudes" (i.e. if we keep travelling to the edge). Hence, they ''must'' attribute falling to [[Intelligent falling|other causes]].

====Density and buoyancy====

The most wrong explanation they have come to is that things fall due to density and buoyancy, which is as good as saying that they fall due to colour. 

Flerfs often use examples of "density-buoyancy towers" of different liquids (eg. water and oil) to prove that relative density is enough to explain the effects of gravity. However, density is just the amount of mass within a volume, so it's not even a force and thus cannot cause acceleration as a result; on the other hand, buoyancy is indeed a force, but it also requires another force in its very formula, which on Earth (''surpise surprise'') is GRAVITY! The force of gravity can be countered by another force, like the centrifugal force of an aeroplane jet (thus allowing pilots to literally drink a glass of water upside down; see below) or on a free fall (in which density towers stop to exist; see below again). Without any force, buoyancy stops working. So, this is a non-starter.

{{collapse|Water falling "up"|width=500}}
A fighter jet pilot can drink water while flying upside down because of the effects of acceleration and how gravity interacts with the body and fluids. The jet’s rotating force and lift counteract gravity in stable, inverted flight, thus allowing water to fall "up" and pilots to pour it upside down.
{{video|youtube|g99ho_ExApU}}
{{collapse end}}
{{collapse|Free falling experiments with density towers|width=500}}
On Earth, density towers of different liquids exist because gravity pulls more strongly on the denser substances, and the less dense ones float on top due to buoyancy. By taking gravity of the equation under microgravity conditions, such as experiments conducted in free-fall/microgravity environments, a density tower ceases to exist and the liquids mix homogenously (this is the reason why bartenders need to shake cocktails) or float around as blobs, rather than separating into layers.

'''Experiment 1''': Video of a density tower with a Ping pong ball attached to two 55g Pb in a free-fall.

{{video|youtube|ACiy61TkdI8}}

* RESULT: The liquids mixed, and the balls attracted to each other.

'''Experiment 2''': Video of two density towers with water and oil in a free-fall.

{{video|youtube|umtG_zMYTok}}

* RESULT: The liquids mixed and formed separated blobs. Inverse layers were formed following the direction of the falling force.

'''Experiment 3''': Video of a density tower with different liquids in a free-falling airplane performing a parabolic flight. 

{{video|youtube|-Jk5zxuTvJA}}

* RESULT: The liquids mixed homogenously.

'''Experiment 4''': Video of Ping pong balls on a glass of water in a free-falling airplane performing a parabolic flight. 

{{video|youtube|rzytpxtbCzQ}}

* RESULT: The balls sank in the water and remained there.

'''Experiment 5''': Video of a Ping pong ball on a glass of water in the Chinese Shenzhou 13.

{{video|youtube|0qEzdxLls5k}}

* RESULT: Same results as before (tho you might hear flatties screaming "CGI").

{{collapse end}}

Alternatively, considering that acceleration towards the ground is a ''function of density'' is at odds with empirical evidence: a feather and a bowling ball reach the ground at the same time in the vacuum.<ref>[https://abc11.com/bowling-ball-and-feathers-ifl-sicence-i-love-science-nasa/382792/ Bowling ball and feathers dropped at the same time in a giant vacuum chamber, ABC 11]</ref> Without air resistance, everything experiences the exact same acceleration when it falls. Also notable is the fact that they rarely explain why being denser should make an object move ''at all'', let alone why it should always do so in the same specific direction. 

Eric Dubay's [https://youtu.be/J7RwAcL4Iq0?feature=shared&t=11318 "explanation"] was: "There is {{wpl|Vertical_pressure_variation|vertical pressure gradient|,}} and that defines the direction." This explanation is a non-starter. Due to the pressure gradient, the pressure below the object is slightly higher than above it, and thus the higher pressure actually pushes the object up, not down. This is why objects less dense than air, such as helium balloons, are pushed up: gravity pulls air below the helium balloon. Also, Dubay's explanation was circular. It failed to explain why the air that supposedly pushes objects down, gets itself pushed down to create the pressure gradient (Hint, Eric: the cause starts with a '''g'''). Even worse, his answer failed to explain the one thing it was supposed to explain: '''Why THAT direction in particular?''' 

As for the vacuum, Dubay [https://youtu.be/J7RwAcL4Iq0?feature=shared&t=11252 claimed] the "infinite density difference between an object and vacuum causes the object to fall down", which is weird, because he just said it was the air that was pushing stuff down. How does ''nothing'' push ''stuff''? Or, why is ''stuff'' always running away from ''nothing'' into the direction where dirt lives? Dubay and flerfs fail to acknowledge that density is a property of a physical object, it doesn't create a force that has an inherent direction. Flerfs also fail to realize that if this ''was'' the case, and density ''does'' make things fall, then the [[Sun]], [[Moon]], and stars would all come crashing down to Earth. But don't worry, those objects are held in the sky by [[Magic|'''M A G I C K''']].

====Everything accelerates "up"====

The [[Flat Earth Society]] has [https://wiki.tfes.org/Universal_Acceleration proposed] that gravity is the result of the Earth accelerating at '''~9.81 m·s<sup>-2</sup>''' in the "upwards" direction. However, this fails to account for the variation of gravitational acceleration across the surface of the Earth from the mass distribution within. E.g., during [[The_Final_Experiment|The Final Experiment]], Critical Think's [[The_Final_Experiment#The_secondary_experiments|weight experiment]] showed close to four gram deviation when weighing a 1kg mass first in Brisbane, Australia, and then in Union Glacier, Antarctica. There's also no explanation as to what energy keeps this acceleration going, as said required energy tends towards infinity the longer it goes on. All celestial bodies would have to be comoving as well, to avoid Doppler shift and all the other quirks of relativistic motion.

====Electromagnetism====

Some flat-earthers, such as the [[YouTube]] channel GlobeBusters,<ref>[https://www.youtube.com/watch?v=JDy95_eNPzM Response to Globebusters - The Earth Still Isn't Flat] by Professor Dave Explains (May 22, 2019) ''YouTube''.</ref> have suggested that it is the electromagnetic force that causes people to fall to the Earth. This is quite similar to [[hypotheses]] posited by [[Electric Universe]] cranks. This runs into multiple problems, however. For one, if it was the electromagnetic force pulling objects to the ground, then objects of different charges would react differently to this force – for instance, neutrally charged objects would not be affected by the electromagnetic charge of the Earth. Another fact that casts doubt on this suggestion is the fact that the acceleration due to gravity '''g''' is constant for all objects in a vacuum at sea level, regardless of mass. However, this would not be the case if the electromagnetic force was the force that pulled objects towards the Earth. Let us consider that, the electric force exerted on an object of charge '''q''' that is within an electric field '''E''' is:

<center>'''F = qE'''</center>

It can be shown that the electric field of a uniformly charged flat disk (which is what flatheads think the shape of the Earth is) is dependent solely on the distance from the disk '''z''', the surface charge density '''σ''', and the radius of the disk '''R'''.<ref>[http://hyperphysics.phy-astr.gsu.edu/hbase/electric/elelin.html Electric Field of Line Charge] by C. R. Nave, ''HyperPhysics, Georgia State University''.</ref> The important thing to note here is that the electric field is '''not''' dependent on the mass '''m''' of the object.

Newton's Second Law states that '''a'''='''F'''<sub>'''net'''</sub>/'''m''', where '''a''' is the acceleration of the object, '''m''' is the mass of the object, and '''F''' is the force exerted on the object. Thus, it stands to reason that if the electromagnetic force was the force that pulled objects towards the Earth, the acceleration of an object in free fall would be '''a<sub>e</sub> = F<sub>e</sub> / m'''. Thus, we would get:

<center>'''a = qE / m'''</center>

However, this would mean that that acceleration of an object in free fall would depend on the mass, even in a vacuum. This is blatantly false, as we know from experiments dropping objects in vacuum chambers that the acceleration of all objects in free fall in a vacuum is the same '''regardless''' of the object's mass.<ref>[https://abc11.com/bowling-ball-and-feathers-ifl-sicence-i-love-science-nasa/382792/ Bowling ball and feathers dropped at same time in giant vacuum chamber, ABC 11]</ref> Thus, the electromagnetic force cannot possibly be the force pulling objects to the Earth.

From Newton's law of universal gravitation '''F<sub>g</sub> = Gm<sub>earth</sub>m<sub>obj</sub>/r<sup>2</sup>''' for an object on the Earth. Since '''g = F<sub>g</sub> / m<sub>obj</sub>''', '''m<sub>obj</sub>''' would cancel out in our law of universal gravitation, and thus '''g = Gm<sub>earth</sub> / r<sup>2</sup>''' is a constant at sea level that is not dependent on the mass of the object. Thus, the acceleration due to gravity is the same for all objects at sea level.

'''Gravity exists''', however, and flerfs like [https://youtu.be/SauZfMS-lZo?feature=shared&t=13673 Dubay] claim it hasn't been shown on Earth. This is a lie. In fact, it has been shown in countless repetitions of the [[Cavendish_experiment|Cavendish Experiment]].

==="So why don't people on the Southern Hemisphere fall off?"===
[[File:Water not sticking to ball2.jpg|thumb|right|'''Flerfs' idea of down''': The reason flerfs think water can't stick to Earth, and why they think people on the Southern hemisphere should just fall off, is because instead the void of space in all directions, they think there's an even more massive land mass below the South pole, towards which everything is falling.]]

[[File:Hildegard von Bingen- 'Werk Gottes', 12. Jh..jpg|thumb|left|200px|This illustration is from about 1170. People understood this concept in the fucking ''Middle Ages.'']]

We kid you not, flatheads ''actually'' use this argument enough — [[poe's_law|believe it or not]] — to warrant us mentioning it. An OG-flat-earther {{wpl|Lady Elizabeth Blount}} (1850-1935), returning from a trip to Australia, stated in a sworn affidavit that the people there did ''not'' hang by their heels.  QED: The Earth cannot be a globe.  It truly says a lot about the level of education of flatheads that use this argument, because this is something that most people get taught in freaking ''kindergarten''.

The reason people in the southern hemisphere don't fly off into space in the direction defined by the Earth's south pole is the same reason people in the northern hemisphere don't fly off into space in the direction defined by Earth's north pole. "South" does not equal "down" any more than "north" does. Even in the flerfs' own model, south means "towards the rim of the pizza land", and north means "towards its center". "Down" means "in the direction gravity is pulling," and thus "up" and "down" are meaningless concepts outside of the context of some object's gravity well. What is "down" for someone at the south pole is "up" for someone at the north pole. Most maps and globes are just printed with north always facing the top because it's easier for everyone using them if the four cardinal reference points always go in the same direction, and they just picked north because the trend was started by those egocentric pricks that were historical Europeans.  In other parts of the world, maps are sometimes oriented differently.<ref>https://www.geographyrealm.com/map-orientation/</ref>

Maybe the most stupid and simple way to make them understand the idiocy of their "argument" is to pick up a ball and ask them what part of it is "up" (or "down"). If they do point to any part of it, just turn the ball "upside down" and ask them again. Now what flatties? You have only two options. Either "up" (or "down") is the part you pointed out first, even though it's now inverted (thus admitting "up" or "down" as absolute concepts are arbitrary); or what you pointed out first as "up" is now "down" and vice versa (thus proving "up" or "down" are relative concepts, to the ground in this case). If it is the former, then that begs the question why is that place "up" (or "down") and things must fall towards it. And if it is the latter, then, do you guys imagine there's ground under a spherical Earth? What?

The confusion might result from flerfs' inability to see the world from other peoples' point of view, or, from their limited spatial reasoning skills. One way to think about this, flerfs, is to realize that your experience about being upside down might be strongly associated with say, past playground experiences: 1) you felt the thing you were hanging from with your legs, and you felt your hair and clothes hanging, 2) you felt blood packing to your head, and 3) you saw things around you upside down. None of those are present on southern hemisphere. Earth is pulling you towards itself so you can stand. It is pulling blood away from your head, and everything else is being pulled down too, so they're in the right orientation and don't seem upside down. Try to imagine yourself to the other side of a globe, and think about how everything's being pulled towards Earth and how it's masking your ability to reason about your position in the space's inertial frame of reference.

{{collapse|Ernie and Bert explain upside down|width=500}}
Being upside down depends on your frame of reference.
<center>{{#ev:youtube|https://www.youtube.com/watch?v=nymXRO7C3Lw|||||start=0}}</center>
{{collapse end}}

==="So why don't rivers flow uphill?"===
Yes. Same argument as before. 

Yes, really, they actually say this.<ref>"[https://www.quora.com/If-Earth-is-spherical-Nile-river-has-to-flow-uphill-to-compensate-the-curvature-of-Earth-Is-this-proof-that-the-Earth-cannot-be-spherical/ If Earth is spherical, the Nile River would have to flow uphill to compensate for the curvature of Earth. Is this proof that the Earth cannot be spherical?]". Quora''.</ref>

Yes. Your mind isn't playing tricks on you, we just got done taking the time to explain this to people who, evidentially, don't get it. TWICE. 

Rivers don't flow uphill. All rivers flow downhill. Some rivers like the Nile River flow '''North'''. Some rivers, like the Mississippi, flow South.

'''North and south are horizontal directions.'''

'''In Globe Earth model, North and South are towards one or the other polar cap.'''

'''In Flat Earth model, North is towards the center of the pizza-land, and South is towards its rim.'''

'''In both models, up is AWAY FROM GROUND, and down is TOWARDS THE GROUND.'''

==="How can Earth pull such massive oceans?"===

Earth's gravitational field is not a strongman trying to hold on to everything. Earth's gravitational field is closer to a hole (in fact it's [https://upload.wikimedia.org/wikipedia/commons/3/39/Deepening_gravity_well.png modeled as such]). A hole doesn't have to do a lot of work for stuff to fall into it. What comes too close to it, will fall into the hole. After that, it takes a space rocket to climb out of that hole. Now, all of Earth's water is chilling in that gravity hole, so it's not going anywhere.

Another way to view this is this: Each water molecule is tiny, and weights about 0.0000000000000000000000299158 grams. Thus, each water molecule will experience about 0.0000000000000000000000002935 Newtons of pull due to gravity. There's roughly 46292400000000000000000000000000000000000000000000000000 water molecules on Earth. But again, Earth's gravity is more of a hole than strongman holding on to them. If you want a strongman analogy, Earth has basically infinite tiny tiny hands that never get tired, holding on to one tiny water molecule each.

==="How can Moon override Earth's gravity and create tides?"===

[[File:Orbit3.gif|thumb|right|Earth and Moon rotating around their barycenter (marked with red '+').]]

This question [https://youtu.be/SauZfMS-lZo?feature=shared&t=14146 comes from] none other than Eric Dubay.

The simple answer is, because the Moon has quite a bit of mass too, 1.2% of Earth's mass.<ref>Dobrijevic, Daisy; Sharp, Tim (Feb. 7, 2022). [https://www.space.com/18135-how-big-is-the-moon.html "How big is the moon?"]. Via space.com</ref> Earth may be much heavier, but that doesn't mean Moon and Earth do not exert gravitational force to one another. Moon's gravity is just smaller. 

All pairs of object in space have a shared center of gravity (called {{wpl|Barycenter_(astronomy)|barycenter}}) that can be calculated. As shown by Dr. Becky [https://youtu.be/Mr89IgzsMVk?feature=shared&t=146 here], the Earth-Moon barycenter is so close to Earth, it's actually inside of it — 4,671km from Earth's geocenter towards the Moon (~3/4 way from the center to Earth's crust).

Note that the center of mass does not have to be inside an object. When Jack and Rose spun around holding hands on Titanic, the center of gravity was somewhere between them. The same can happen between two objects in space. In fact, the barycenter of Pluto and its largest moon, Charon, lies in the space between them.  Thus, the barycenter itself does not necessarily pull anything towards itself on its own, but it makes it easier to think about how both the Earth and the Moon affect things they pull.

Because water is a liquid, its molecules can move relatively freely. Because of this, the water molecules find their level around the barycenter. This causes the bulge on the Moon's side, that on open ocean is about [https://manoa.hawaii.edu/exploringourfluidearth/physical/tides/tide-formation-gravitational-pull one meter high]. 
<ref group=note>Tidal forces pushing large amounts of ocean water to narrow passages at the coastline will make the tides locally often much higher than the open ocean bulge.</ref> At the surface of the bulge, the gravitational pull of the Moon and Earth cancel out, and thus a limit is set to bulge height.

Because Earth's own center of mass rotates around the barycenter, it's again like Jack spinning with Rose on the lower decks. This centrifugal force causes the water to bulge on the opposite side of the globe. The height of the bulge is defined by the distance where gravity is cancelled out by the centrifugal force (gravity and tides being different things). The centrifugal force also acts on the Moon's side of Earth, reducing the bulge slightly.

=== "So why do lakes not have tides?" ===

[https://youtu.be/SauZfMS-lZo?feature=shared&t=14178 Asked] Dubay. They do. It's just much less water, so the effect is hard to see. Even the Great Lakes have tides of about 5cm (2 in).<ref>NOAA [https://oceanservice.noaa.gov/facts/gltides.html "Do the Great Lakes have tides? "]. Via noaa.gov.</ref> Since scientists [https://www.youtube.com/watch?v=jSrH7MqNDXQ&t=86s consider] even Great Lakes non-tidal, it's no wonder smaller lakes and ponds, let alone puddles, show no visible tide.

==="But tides are caused by the gentle and gradual rise and fall of the Earth from the bosom of the mighty deep!"===

[https://youtu.be/SauZfMS-lZo?feature=shared&t=14225 Claims] Dubay. So much for the flerfs' stationary ground. Anyway, since there's exactly zero evidence of this, it's up to Dubay to go to the nearest seaside shore, and use an accelerometer or [https://www.youtube.com/watch?v=ZLS8KD_BnYU seismograph] during the tide to show there's an earthquake everywhere that we can't see or feel. If needed, [https://youtu.be/R3LjJeeae68?feature=shared&t=266 here] is Sabine Hossenfelder explaining how a spring can be used to detect the shoreline rocks accelerating up or down with the tides, no matter the frame of reference.

Until then: {{wpl|Hitchens's_razor|Asserted without evidence, dismissed without evidence|.}}

==="How can Earth drag the atmosphere along but birds and bugs can fly? Why can humans jump despite air pressure?"===

We can't believe this needs to be explained but just in case [https://youtu.be/SauZfMS-lZo?feature=shared&t=2351 Dubay is serious] [https://youtu.be/SauZfMS-lZo?feature=shared&t=13815 with] [https://youtu.be/SauZfMS-lZo?feature=shared&t=14071 these], here we go.

Large birds are quite heavy, so gravity affects them more. As can bee seen [https://www.youtube.com/watch?v=lwhmNC4yhvU here], an Albatross will have to work hard to take off. A Common Loon will [https://www.youtube.com/watch?v=DShnJDhPwy0 work even harder]. Some large birds have stronger muscles and wings which makes it easier for them, e.g., the [https://youtu.be/Obdr_GRkUlw?feature=shared&t=10 Andean Condor]. The smaller [https://youtu.be/OSvsxKgecpo?feature=shared&t=175 Peregrine Falcon] is the fastest bird out there.

Large bugs, like the [https://youtu.be/DjgpyDmhVJc?feature=shared&t=4 Goliath Beetle], struggle with taking off. Small bugs, on the other hand, have small muscles and wings, but as they're also very lightweight, gravity doesn't affect them as much. Small bugs can accelerate, and fly at ridiculous speeds, the record holder being the 12mg heavy [https://www.speedofanimals.com/animals/horsefly Horse Fly], that accelerates at about 25G, and that has top speed of 145km/h.

Air moves with the Earth because it has {{wpl|Viscosity#Air|viscosity|.}} If you do not know what that is, see [https://www.youtube.com/watch?v=VvDJyhYSJv8 this] video. The viscosity of air is what causes air resistance, that sets limits to how fast we can ride our bicycle. The viscosity of olive oil is 56.2 mPa·s, that of water is 1.0016 mPa·s, and air's is 0.0000185 mPa·s. 

Earth can't of course get the air to spin up immediately. You can test this with a glass of water. Try rotating a pen in the water one full circle, and you'll see water just circle around the pen. Next, try ten full circles. and witness the small whirlpool. This can also be done by rotating the liquid from its edges. See [https://www.youtube.com/watch?v=8gnhTg_bLVg&t=47s here] for an example. Air which is like liquid, a fluid, will do that too, just, at slower acceleration because of its lower viscosity. 

Because the Earth, its atmosphere, all bugs, and all birds have same angle speed around Earth's geo center, there is no relative movement between them. Thus, Earth's rotation doesn't affect birds or bugs flying. Winds are air currents that result from temperature differences, and those do indeed affect flying things, sometimes [https://www.youtube.com/watch?v=d5QVkgmk6co quite a bit].

Humans can fight off gravity with relative ease for brief moments. This is because the muscles have small amounts of their main fuel, {{wpl|Adenosine_triphosphate|ATP||,}} that enables explosive movements like jumping. When ATP runs out, we make more from our {{wpl|Phosphocreatine|creatine phosphate|}} stores. More energy is fed to this system from the body's glycogen stores. Too strenuous exercise, or running out of glycogen while e.g. [https://youtu.be/sYtAhXDyaxM?feature=shared&t=357 cycling up-hill], will make gravity quite real.

The pressure of air will not affect its viscosity nearly as much as temperature does. Compare e.g. fridge cold honey with the one left on a table overnight. Next, increase the air pressure inside the honey bottle by squeezing it hard from the sides and cap, turn the bottle upside down, and see how much that affects how the honey can move through the air.

As for pressure preventing jumping, the pressure is all around us, so it's not preventing jumping more than air resistance will. An extremely high-pressure air would be really cold, and liquid form. Air is 70% Nitrogen, the -196°C {{wpl|Liquid_nitrogen|liquid form}} of which has 1/30 the viscosity of room temperature water. We can still move in water that's liquid although running in it is difficult. Moving in liquid nitrogen would be 30 times easier than moving in water, if it didn't [https://youtu.be/_OlGH8z-4Qk?feature=shared&t=7 quickly freeze us to death].

In reality, the air around us is '''helping''' us jump, by a little bit: Since humans are roughly as dense as water, a 100kg individual will displace roughly 0.1 m³ of air. Air has density of 1.2kg/m³, so that individual will displace 0.12kg = 120 g of air. The air creates a buoyant force (that's why helium balloons go up), which makes the individual 120g lighter.

==="But how can long jump be longer than the height to which I can jump?"===

Eric Dubay [https://www.youtube.com/watch?v=SauZfMS-lZo&t=14091s wonders]. Gravity does not inhibit your ability to move around Earth's core. The answer is, it only inhibits moving away from the core. You can jump up or up and forward. A long jumper jumps further when they gain momentum for jump by building up speed. At the jump face, the forward directed inertia moves the jumper forward, and the jump motion pushes the athlete forward and up, so it increases two speed components. The long jumper will be in the air exactly as long as determined by the vertical speed component that the jumper has when their feet stop touching the ground. The formula for that airtime is (excluding air resistance) '''t = 2v / g''' where '''v''' is the vertical lift-off speed in meters per second and '''g''' is the acceleration due to gravity ('''9.81m/s²'''). E.g., if the time of flight is say 1.2 seconds, and the long jumper's total horizontal movement speed is '''8 m/s''', then the distance covered during the jump will be '''8 m/s ✕ 1.2s = 9.6''' meters. Dubay could really have benefited from taking high school physics class.

==="But how can a pressurized atmosphere exist next to a vacuum?"===

[[File:Homemade fusion reactor.JPG|right|315px|thumb|Photo of a {{wpl|fusor}} reactor with plasma (ionized gas) inside a vacuum tube. A force holds the plasma next to a vacuum, electromagnetism in this case. No barrier needed. A similar thing happens with the atmosphere and gravity. PS: This is an analogy. Gravity IS NOT electromagnetism (See: [[Electric Universe]]).]]

Flat-earthers, like creationists (which they often are) love to misrepresent the [[second law of thermodynamics]], claiming that Earth's atmosphere violates it if it is not contained by some "dome". What they're asking is basically why the Earth's pressurized atmosphere doesn't equalize with the vacuum of space without a protective barrier. According to [https://flatearth.ws/thermodynamics flatearth.ws], their basis for gas needing a container, is willful misinterpretation of [https://www.youtube.com/watch?v=QrzHB9_kHPE&t=1370s this MIT thermodynamics lecture].

We'll answer this question with another question: where's the barrier between high-pressure sea-level air and low-pressure mountaintop air? As height increases, air pressure and concentration decreases, approaching zero after a certain height. Meaning, even if the Earth was flat, the atmosphere would have to end at some point.

This is due to the scientific illiteracy of flat-earthers who can only imagine the vacuum on space as a literal vacuum cleaner. It does not “suck” the air. Flat-earthers associate the word “suck” with “vacuums” but it’s a misnomer. That’s not what actual vacuums do. That’s what vacuum ''cleaners'' do. What they <i>really</i> do is use a [https://www.youtube.com/watch?v=BaEHVpKc-1Q centrifugal pump to create a pressure differential], and the higher pressure air in the room then expands to fill the empty space through the hose, at very high speed. However, [[gravity]] pulls the air back down, so we can breathe air.<ref>[https://flatearth.ws/thermodynamics Misconception about the Second Law of Thermodynamics]. flatearth.ws.</ref> As the Earth traverses its orbit, the atmospheric particles around the Earth reach a {{wpl|Hydrostatic_equilibrium|hydrostatic equilibrium}} where the compression resistance of air cancels out the compression force of gravity. Gravitation pulls the atmosphere in so the amount of gasses that {{wpl|Atmospheric_escape|escape}} Earth on the trailing side of its orbit remains minimal.

It's odd. Nobody with even a microgram of sanity would deny that things fall, not even flatheads. But all of a sudden, when atmospheric pressure and the vacuum of space are being discussed, that "things fall" aspect of reality suddenly doesn't exist to flatheads.

==="But there are no experiments showing pressure gradients can be created"===

[https://youtu.be/ghWfhMDRIqU?si=e2JhutkMULCtfszz&t=376 Barks] Dubay.
While it is difficult to create a pressure gradient on Earth without it being overpowered by the one produced by Earth's gravity, an even stronger one can be created by means of an ultracentrifuge; this is how {{wpl|Zippe-type_centrifuge|centrifugal isotope separation works}}, for instance. A centripetal acceleration of several hundred thousand times Earth's gravity (needed to magnify the tiny relative buoyancy of the lighter isotope to useable levels) is capable of creating a gradient from close to atmospheric pressure to near vacuum over 10cm. To flerfs: Would it be expensive to buy and possibly modify a commercial ultracentrifuge to conduct the experiment? Possibly, but it's at least possible to do it on Earth, so it's probably safer than trying to see the curve of the Earth using a rocket.

==="But they fake the ISS footage with Zero-G planes!"===

Dubay, who [https://youtu.be/SauZfMS-lZo?feature=shared&t=14596 claimed] this, used a graph by the [https://www.gozerog.com/ Zero-G] company, that shows the zero-G phase of the plane lasts for 25 seconds, during which the plane climbs from 32,000ft to 33,000ft. That's 1000ft of climb for 12.5 seconds and drop for another 12.5 seconds. You can continue to drop as long as you like until you die.

The Zero-G phase happens when Earth's gravity pulls the plane down at exactly the same rate as its passengers, effectively canceling their weight. During this time, the plane continues upward until it hits the peak of its arc. At mid-point of the 25 second experience, the plane will start to fall. At that point its speed is 0m/s. After the fall part of the zero-G, 12.5 seconds later, the plane will be losing altitude at '''12.5s ✕ 9.81m/s² = 122.6m/s'''.
    
According to the graph Dubay showed, the plane is at 32,000 feet, or 9,750 meter altitude at that point.
    
We can do some basic physics and get the ISS footage filming time before everyone dies in a horrible plane crash: 

'''t = 25s + √(2h/g) = 25s + √(2✕9750m / 9.81m/s²) = 25s + 44.5s = 69.5s'''

So just shy of 1 minutes 10 seconds to film the footage. So, [https://youtu.be/XkM_04Ch76E?feature=shared&t=142 here] is a just under '''SIX MINUTES LONG''', continuous shot from the ISS. [https://www.youtube.com/watch?v=AErpXJq67LM Here] is some more if you feel like it.
    
'''"Why not just climb higher with the plane?"''' 

Because the pressure gradient of the atmosphere means the air gets thinner the higher you go. Each plane has a maximum altitude called {{wpl|Ceiling_(aeronautics)|ceiling|,}} where the air can still provide lift. The ceiling of the {{wpl|Boeing_727|Boeing 727}} that Zero-G uses, is 42,000ft (13,000m). But just for the shits and giggles, we can ignore that, and calculate the height of the fall, that would allocate 5 minutes of continuous filming time while falling:
    
'''h = ½gt² = ½ ✕ 9.81m/s² ✕ (300s)² = 441.5 km.'''

441.5 km is… …the flying altitude of the ISS. So. If we could fly a plane that high to fake the footage, why not put a fucking space station there while we're at it?
===The long ISS shots used wire harnesses and green screens!===

Debunking this relies exclusively on analyzing video footage, so we're going to hand it over to Dave McKeegan, who did absolutely fantastic job debunking crank claims about the [https://www.youtube.com/watch?v=y_XB4j4vVXo original] [https://www.youtube.com/watch?v=iV-X0NcG8Lc clips].

{{collapse|ISS Greenscreen debunks by Dave McKeegan|width=500}}
{{#ev:youtube|https://www.youtube.com/watch?v=3M01m3UUgoM|||||start=0}}
{{#ev:youtube|https://www.youtube.com/watch?v=d6PucIgX6Sw|||||start=135}}
{{collapse end}}

==="How is it that gravity can cause planets to revolve elliptical orbits around a single center of attraction?"===

[[File:Solarsystem orbits 300 dpi.png|thumb|right|The elliptical orbits of planets with accurate eccentricity values. See [https://pastebin.com/ggCPmxtG here] for source code.]]

This question [https://youtu.be/SauZfMS-lZo?feature=shared&t=13828 comes from ] Eric Dubay. Dubay continues: "''Ellipses by nature require two foci, and the force of gravitation would have to regularly increase and decrease to keep planets in constant orbit and to prevent pulling them to direct collision courses.''"

The '''r²''' in the [[File:Newtons law of universal gravitation.svg|100px]] <!-- <math>F_g = G \frac{m_1 m_2}{r^2}</math> --> ({{wpl|Newton%27s_law_of_universal_gravitation|Newton's law of universal gravitation|}}), states that gravity increases as the square of distance. So yes the gravitation increases and decreases constantly.

As for the collision courses, the {{wpl|Orbital_eccentricity#Examples|elliptical orbits of solar system's planets}} have very small eccentricity (deviation from perfect circle). See the image on the right for an accurate representation. From the image it's clear the planets are nowhere near a collision course.

==="But if someone digs through the Earth, they will come out the other side with their feet up!"===

This lovely thought experiment [https://youtu.be/ALWFJYF1jm4?si=ZnLgFZld5YfuNZBF&t=202 comes from] Dubay.

Suppose two people start digging at the same time. They dig to the center of Earth, and by the time they reach the geocenter, their feet will still face each other. They shake hands and climb out of the opposing guy's hole. The gravity immediately starts to pull them towards the geocenter. Why would they climb out of the 3,963 miles (6,378 kilometers) deep hole in the ground, feet first? Dubay apparently trusts the reader to have zero spatial reasoning skills to realize, that to climb up, i.e. away from the center of Earth, humans usually orient themselves head towards the direction of travel and feet towards where they're coming from: the geocenter. So again, if you climb down the hole that goes through the Earth, at the center you'll feel like you're in space or Zero-G. You then grab onto the ladders. Initially, it feels like you don't weigh anything, and slowly as you walk up, gravity gets stronger as more of Earth is behind you pulling you down, and less of Earth is in front of you, pulling you up.

If you'd dig a hole through the Earth and jump in, you would, as seen in the video below, just be oscillating through the Earth until air resistance would slow you down and you'd be stuck hovering in the middle.

{{collapse|Falling through the Earth|width=500}}
{{video|youtube|McpJCBD5RTY}}
{{collapse end}}

==Magnetism==

===If the Earth was flat, compasses in Antarctica would have their needle point North, through the Earth.===

[[File:Magnetic Dip.svg|thumb|200px|right|{{wpl|Magnetic dip}} causes the compass to tilt up or down depending on latitude.]]

[https://youtu.be/a7pd-TH-grI?si=XpWN5PKQkXfvU5mT&t=1284 Claims] Dubay clearly doesn't know how magnets or the Earth's magnetic fields work. As the image on the right shows, the magnetic field protrudes almost vertically at the poles. This means that in the southern hemisphere, it would be the south-pointing needle that points down. Which, as [https://www.youtube.com/watch?v=XJZ9fcsyNcw&t=93s this video] shows, it does. See {{wpl|Magnetic dip|Magnetic dip|.}}

==Rotation==

==="So how can water stick to a spinning ball?"===
[[File:Flying through the water! (Unsplash).jpg|thumb|left|200px|Flatearthers often use examples of a spinning wet ball throwing water away to “disprove” spherical Earth. In reality, that tennis spins a thousand times faster than Earth.]]
[[File:Bottrop - Kirchplatz - Kugelbrunnen 02 (0) ies.ogv|thumb|right|200px|{{wpl|Kugel fountain|Kugel fountain}} in Bottrop, Germany. Look flat-earthers! Water sticking to a spinning ball!]]
This is a surprisingly common question and reveals how unwilling flatties are to do a single mathematical calculation. On a rotating sphere, all points in a longitude have the same angular velocity, but as the latitude tends to 0, the tangential velocity increases to its maximum, and so does the centrifugal force. A point on the equator travels 40,075 km (Earth's circumference) in 86,164 s (a sidereal day), yielding a linear speed of 0.465 km/s, or 1,674 km per hour! Everything should fly into space, right? No.

Centrifugal acceleration can be derived to be: '''a = ω²'''

where '''r''' is the radius and '''ω''' is the angular velocity. With an equatorial radius of '''m = 6.3781×10<sup>6</sup>''' and rotational period of 86,164 seconds ('''ω = 7.292×10<sup>-5</sup> s<sup>-1</sup>'''), an object at the equator must be accelerated 0.0339 ms<sup>-2</sup> downwards to stay on Earth. Although gravity varies from place to place, this is far exceeded by the approximate 9.81 ms<sup>-2</sup> provided by gravity.

For anything to fly upwards, either gravity would need to be '''1/290''' of what it is currently, or a (sidereal) day would have to be shorter than 5066 seconds (1 hour, 24 minutes and 26 seconds) long, i.e., the Earth would have to rotate 17 times faster.

But really, perhaps the best way to demonstrate the stupidity of this one is to ask the flathead to dunk themselves in water and then spin in a circle at the rate of one revolution per 24 hours.

==="Why do cannon balls fired East not have more range, and those fired West, less range?" ===

[[File:Dechales-Coriolis-Cannon.jpg|thumb|200px|right|Illustration from C.F.M. Dechales'  book ''Cursus seu Mundus Mathematicus'' from 1674, that shows a cannonball should deflect to the right of its target on a rotating Earth, because the rightward motion of the ball is faster than that of the tower.]]

Classic [https://youtu.be/SauZfMS-lZo?feature=shared&t=1687 Dubay], missing out on 400 years of scientific progress.

That actually happens, from the PoV of the inertial frame of reference. If you don't know what that is, watch [https://www.youtube.com/watch?v=wD7C4V9smG4 this brief tutorial] by Dave Farina. Basically, if you could hover above Earth without being influenced by it at all, and put markers that hover in the air and stay in the inertial frame of reference, the cannonball would fly further East when fired East, and vice versa.

{{collapse|ELI5 on why this is the case|width=500}}
Imagine a train with glass walls, going on tracks that go from East to West. The train is travelling East. You're on that train, and facing the front (where the locomotive is). Before you is a wastebasket, 3 meters away. Right at the moment when you pass a marked telephone pole outside the train, you throw a ball into the basket. Let's say it takes exactly 1 second for the ball to hit the basket. Then you repeat the experiment. This time, you are facing towards the back of the train, and the basket is again 3 meters in front of you. You throw the ball at the telephone pole mark, and 1 second later, the ball hits the basket.
To you, the experience was the same. The ball travelled 3 meters in one second and hit the basket.

But to Dr. Strange looking at your actions from the outside of the train, from South of the tracks [i.e., they're facing North and the train travels from West (left) to East (right)], it won't be.

Exactly one second after he sees you throw that ball, he will also see it hit the ground. In the first example, because the train is going East and the ball is thrown East, the ball is moving East 3m/s faster than the train. So one second later it will land on the train's floor, and at that moment Dr. Strange stops the time, and they go draw a chalk line above the track tie that's below the ball.

In the next experiment, to Dr. Strange, the ball that's thrown West will still move East, but 3m/s slower. The moment it hits the floor he again stops the time. This time the ball has not moved as fast as the ball in the first example, so it will not have traveled as far in one second time. The bystander will draw the chalk line to different track tie. The distance difference between the chalk marks will be 6 meters.

So, even though you threw the ball exactly 3 meters in both cases, the marks on the track ties are different to someone looking at you from an inertial frame of reference.

Now, replace the train with Earth, and bystander by guy hovering in space untouchable by Earth's forces, observing. Also, replace throwing the ball with a cannon firing a cannonball. Same exact principle. 

To the bystander, the cannonball will fly further when it's fired East because the Earth's rotation gives it more speed. But since the cannon and target are fixed to the ground, the target is floating away from the cannon at the same speed, so flying East does not give an advantage in the battlefield. Similarly, if the cannon is fired West, to the inertial observer, the west-moving cannonball is actually moving East, but slightly slower than the target that's moving East faster. 

The frame of reference will always appear still to the observer. If you attached a GoPro camera to the target, it would look like the cannonball is flying towards it from the distance. On the other hand, if the GoPro is attached to the cannonball to make it the observer, it would look like the world is flying towards the cannonball. This feels really weird and that's normal. We instinctively know we move through the world, not that we stand still while Earth rearranges itself around us. So why should Earth be any different? Why assume it’s motionless instead of a giant rock ship cruising around the Sun at 30 km/s?
{{collapse end}}

Dubay also misrepresented the case by [https://youtu.be/SauZfMS-lZo?feature=shared&t=1956 implying] revolving Earth would not influence cannons. Dubay effectively lies by omission, by not being transparent about the fact, that Earth's rotation and the resulting Coriolis force was known to influence cannon shots' accuracy in the 17th century. See the image on the right.

The fact is, Earth rotation is a very important factor taken into account in ballistics, whether it's a sniper firing bullets at extreme distances,<ref>{{Cite web |date=2022-07-07 |title=Shooting Distance and the Magnitude of the Coriolis Effect |url=https://flatearth.ws/sniper-coriolis |access-date=2025-02-19 |website=FlatEarth.ws |language=en-US}}</ref><ref>{{Cite web |date=2018-06-26 |title=Long-Range Snipers and the Coriolis & Eötvös Effects |url=https://flatearth.ws/sniper |access-date=2025-02-19 |website=FlatEarth.ws |language=en-US}}</ref><ref>{{Cite AV media |url=https://www.youtube.com/watch?v=jX7dcl_ERNs&ab_channel=Gunwerks |title=Demonstrating how Coriolis effects bullet drop at 1000 yards |date=2013-05-24 |last=Gunwerks |access-date=2025-02-19 |via=YouTube}}</ref> or a launcher firing rockets or missiles.<ref>{{Cite web |title=Physics KS3 / GCSE: Using Earth’s rotation to launch a rocket |url=https://www.bbc.co.uk/teach/class-clips-video/articles/z48ygwx |access-date=2025-02-19 |website=BBC Teach |language=en-GB}}</ref><ref>[https://apps.dtic.mil/sti/tr/pdf/AD0731662.pdf THE MOTION OF BALLISTIC MISSILES] by L. S. GLOVER and J. C. HAGA (1971)</ref>

==="Why do cannonballs shot towards the zenith fall to the same place and not Westwards?"===

In his [https://youtu.be/SauZfMS-lZo?feature=shared&t=1586 video] Eric Dubay talks about experiments that have tried to prove Earth's rotation by firing cannons towards the zenith. According to Dubay, the cannon balls with their on average 28 seconds time of flight land "within few feet of the cannon, sometimes back to the muzzle." He then states that if the Earth was a globe, its tangential velocity of 600-700 mph at the testing latitudes of England and America, should have caused the cannonball to fall 8,400 feet behind [West] of the cannon."

Dubay does not cite exact experiments. According to [https://www.researchgate.net/publication/338347971_Before_Foucault_The_Proofs_of_the_Earth%27s_Rotation this paper], the most famous experiments by {{wpl|Marin_Mersenne|Marin Mersenne}} and {{wpl|Pierre_Petit_(engineer)|Pierre Petit}} took place in late spring of 1638 in the surroundings of Paris — not England or America.

The experiments failed to prove Earth was rotating. However, Galileo's famous {{wpl|Galileo's_ship#1632_thought_experiment|Large Ship thought experiment|,}} of which you can watch a tl;dr video [https://www.youtube.com/watch?v=0YrDXU1Ll4k here], explained why that was the case with {{wpl|Principle_of_relativity|relativistic}} motion. Basically, when the cannon is fired up, the cannonball retains its tangential velocity. Same principle can be seen in e.g. [https://youtu.be/-R5cIVt_shg?si=7lmpl_pkPxBOWRtD&t=320 this] video.

However, as explained [https://physics.stackexchange.com/questions/398394/why-does-a-cannon-ball-shot-straight-up-come-down-almost-exactly-where-it-was-sh here], due to Coriolis force, there will be a small deviation. A 10 seconds fall time would cause a 10cm deviation. [https://physics.stackexchange.com/a/398410 Another estimate] states that with zero drag, the Coriolis force at the equator would lead to 8m deviation, but notes that air resistance would reduce it substantially. The cannonball thus will definitely not fall 8,400 feet West, like Dubay claims.

=== "But the Coriolis effect is fake!" ===

The effect is real, but some equatorial tourist traps have grifters performing [https://www.youtube.com/watch?v=ev73aTi5WoM crank demonstrations] of it. Tubs do not demonstrate the Coriolis effect, they only show which way the chaotic system caused the whirlpool to form. No scientist is arguing this yet Eric Dubay who [https://youtu.be/NP912mNKvAQ?si=FldXTorU-FPbZYPE&t=1013 hates ]the straw man fallacy [https://youtu.be/aKgpc1LBL1M?si=K7JvkjSHr1d8T47e&t=16 constructed] a straw man out of it. The real Coriolis force affects winds, and the winds affect the ocean currents.

For a brief explanation what the Coriolis Effect is, see [https://www.pbslearningmedia.org/resource/nvcl.sci.earth.coriolis/the-coriolis-effect/universe/ this video]. The Coriolis force is the result from Earth's rotation, so naturally, flerfs will deny it exists at all. Some will argue it is not a real force, and they're right in that it is what's known as a {{wpl|Fictitious_force|fictitious force|.}} However, that doesn't make it, or its cause and effects, any less real.

Showing the Coriolis effect from the ground is next to impossible because even the largest tornadoes sometimes rotate in the {{wpl|Anticyclonic_tornado|opposite direction|.}} Commercial airplanes don't fly near storms, so the option remaining is satellites. Weather satellite feeds [https://www.youtube.com/watch?v=6CXRlXlB_Dw show] the cyclones rotating counter-clockwise in the northern hemisphere, and clockwise in the southern hemisphere, proving the Coriolis effect without breaking a sweat. As always, flatties deny those feeds as CGI, because of course they do.<ref group=note>Note: Saying something is CGI does not prove it's CGI anymore than [[Argument_from_desire|saying "Bible is the true word of God", makes it the true word of God.]]</ref>

==== "But gyroscopes do not show 15° per hour drift!" ====
[https://youtu.be/a7pd-TH-grI?si=YmOAYBBQ7gnEzteO&t=1073 Says] Eric Dubay, claiming there are no videos that show it. So, [https://www.youtube.com/watch?v=xNYW8JWMVOY&t=1128s here's a video] that shows it. But perhaps if flat-earthers would themselves splurge on an ultramodern ring laser gyroscope and get the true results? Well [[Flat_Earth#Bob_Knodel.27s_RLG_experiment_.282018.29|that was $20,000 well spent]].

==="But with 24 hours per Earth's rotation, it would be daylight during night hours six months from now!" ===

[https://youtu.be/WlNhPXCH5cA?si=WpBONUdlAeNxCtm7&t=30 Claims] Eric Dubay.

'''First, we must define some terms and constants'''

Earth will rotate 360° around its axis in one {{wpl|Sidereal_time|'''sidereal day'''|,}} the length of which is approximately 86164.0905 seconds, or, 23.9344696 hours, or, 23 h 56 min 4.0905 seconds. This means Earth will rotate '''360° / 86164.0905 s = 0.004178075° / second'''.

Suppose on day 1 we see the Sun at zenith at midday, 12:00:00 to be precise. We then measure the angle of the Sun on day 2, exactly 23 h 56 min 4.0905 seconds later, i.e., the moment Earth has turned full 360°. We look at the stars, and see we have indeed made precisely one revolution around our axis. But what we will also observe, is that the Sun on the sky appears, from our perspective, to have only rotated 359.0144° from where it was. This is because Earth revolves around the Sun and after one 360° revolution, Earth will have moved from its original position, and in the new position, Sun won't shine from the same angle anymore. From our perspective, that means we have to wait for the Sun to move another 0.9856° which takes 0.9856° / 0.004178075°/s = 235.89811097 seconds, or, 3 minutes and 55.899 seconds. After the time has passed, the Sun will again be exactly at its zenith. 

The total time it took to accomplish this, is called a '''solar day'''. According to {{wpl|Solar_time|Wikipedia|,}} The length of a solar day is not exactly 24 hours = 86400 seconds, but depending on the season, due to Earth's elliptical orbit where the speed varies a bit, the solar day can be 21 seconds less, or 29 seconds more than 86400 seconds.

'''What time of day will it be exactly on the opposite side of the Sun, i.e. after 180° revolution, and how high will the Sun be?'''

Let's suppose it's January 1st, the time is 12:00:00, and the Sun is exactly at its zenith.

Earth rotates 360° around the Sun in one '''sidereal year''', the length of which is 31558150.0 seconds, or, 8766.15278 hours, or, 365 days, 6 hours, 9 minutes, and 10.0 seconds.<ref>AIAA [https://www.aiaa.org/docs/default-source/uploadedfiles/membership-and-communities/stem-k-12-outreach/aerospace-micro-lessons/aerospace-micro-lesson-20----how-long-is-a-year.pdf?sfvrsn=536305d7_0 "How long is a year"]. Via aiaa.org</ref>

As the sidereal year takes exactly 31558150.0 seconds for 360° revolution, half of that (180°) will take 31558150.0 / 2 = 15779075.0 seconds. Quick math shows us 15779075.0 seconds is 182 solar days, 15 hours, 4 minutes, and 35 seconds. When that time has passed, the date is July the 2nd, and the time is 03:04:35 AM. So indeed, at the exact moment Earth is on the opposite side of the Sun, it will be early morning.

What about the position of the Sun? The Sun will have crossed the zenith point 182 times. In addition to that, it's been 15 hours, 4 minutes and 35 seconds, i.e. 54275.0 seconds since the last time it was at zenith. Since again, the Sun moves 0.004178075° / second, the Sun will have moved 226.765° from zenith, so if you'd face North, with zenith at position 12 of a clock-face, the Sun would shine from the direction of roughly 4 o'clock, moving counter-clockwise towards the sunrise in the East. I.e., it will be roughly first light of dawn. The question is---

'''Who cares?'''

We humans never discuss things like "''What are your plans on the exact opposite side of the Sun?''", or, "''So where are you 182 days and 15 hours from now?''". The absolute position or the moment we reach it never matters to us. We live by our solar day calendar, which means, we get up at seven in January when it's still dark, and we get up at seven in July, and pay no special attention to the Sun being higher.

As we live our 24 hour cycle, the nearest zenith on the other side of the Sun will instead happen 8 hours, 55 minutes and 25.0 seconds, or, 32125.0 seconds later than we had assumed. During that zenith, total of 15779075.0 + 32125.0 = 15811200.0 seconds will have passed, and that means the Earth will have orbited 15811200.0s / 31558150.0s * 360° = 180.366466°.

In other words, what happens is, that we go on about our daily life without caring too much about the fact it's a random time like four past three in the morning when we pass the 180° mark. We also don't care if the closest solar mid-day six months later is a random angle such as 180.366466°  

After one sidereal year, i.e. 31558150.0 seconds, it will be 31558150.0 / 86400 = 365.25636 solar days later, which means the time will be 0.25636 days, or, 6 hours 09 minutes 09.5 seconds later. This means our calendar for 365 days was just over six hours too short.

'''But surely that accumulates error and causes drift of seasons!'''

It does. Too short a calendar means January is drifting towards the previous fall. In other words, during our 365 solar day calendar year, Earth doesn't quite make the trip around the Sun. Four years later, the Earth is about 24 hours behind schedule. This allows us to re-align our calendar, by adding one day (February 29) to it, during which we give time to Earth to catch up with its orbital position from four years prior. And this is why we have {{wpl|Leap_year|leap years|.}}

Congratulations! Flerf cultists can no longer scam you with simple calendar math.

==Climate==

==="So why does a negligible increase in distance towards the Sun cause such temperature difference at the poles?"===

Another great question [https://youtu.be/SauZfMS-lZo?feature=shared&t=8520 from Eric Dubay]. The {{wpl|Interplanetary_dust_cloud|interplanetary dust cloud}} absorbs a negligible amount of Sun's radiation, so it's not the distance that defines the amount of Sun's radiation. It's the angle at which the sunlight reaches Earth, as explained by Dave Farina [https://youtu.be/KyD8VIK032o?feature=shared&t=873 here]. One would think flerfs know about this since it's in their [https://wiki.tfes.org/Temperature_Variations own story] too.

==="So why isn't the climate, flora and fauna on the North Pole and Iceland similar to Antarctica?"===

[https://youtu.be/SauZfMS-lZo?feature=shared&t=7369 Asks] Eric Dubay. Antarctica is a continent. The polar cap is a big floating block of ice with snow on top. Water acts as a heat reserve during winter, and it warms less during summer. Also, the {{wpl|Gulf_Stream|Gulf Stream}} carries warm seawater from the Gulf of Mexico towards the polar cap which further warms it. Iceland is land, surrounded by the Atlantic Ocean, and near the Gulf Stream, so it gets to enjoy a bearable climate and some flora and fauna.

North Pole has no plants, because plants like to grow in soil, which ice isn't, and animals do not read brochures about where else the globe has similar conditions, and make arrangements to move there. Why would Polar bears evolve on Antarctica just because it's cold there?

==="So why is there a ''"dome"'' in Antarctica?"===

Some flat-earthers have attempted to cite the 1958 Encyclopedia Americana which states that there is "a dome 13,000 feet high" in Antarctica. And yes! There are domes in Antarctica! {{wpl|Dome (geology)|Geographical}} {{wpl|Glacier_morphology#Ice_domes)|ice domes}}... and [https://youtu.be/dTRKCXC0JFg?t=8 "I do not think it means what you think it means"...]<ref>See {{wpl|Dome A}}, {{wpl|Dome C}}, {{wpl|Dome F}}</ref>

==Navigation==

=== "But pilots use flat Earth maps for navigation!" ===
[[File:Triangles (spherical geometry).jpg|thumb|right|300px|Long-distance navigation would be impossible if we were wrong about the shape of the Earth. Either everyone involved with travel and international business is in on the conspiracy, [[Occam's razor|or flat-earthers are stupid]].]]

Of course, pilots are taught and trained to navigate on spherical Earth
<ref>{{Cite web |date=2020-10-01 |title=Pilots Are Taught to Work With the Fact Earth is a Sphere |url=https://flatearth.ws/pilot-education |access-date=2023-04-02 |website=FlatEarth.ws |language=en-US}}</ref><ref group=note>Software used by pilots for planning flight routes such as ForeFlight, SimBrief, or SkyVector don't use the "flat Earth map" (in fact, they use a globe).</ref> 
and they openly admit flat Earth is stupid
<ref>{{Cite web|title=Proving The World is Flat! |url=https://www.youtube.com/watch?v=xaRxOesKIyg |access-date=2023-04-02 |language=en}}</ref> 
(especially when they are not harassed by flat-earthers).
<ref>{{Cite web |date=2021-05-30 |title=Asking Pilots |url=https://flatearth.ws/asking-pilot |access-date=2023-04-02 |website=FlatEarth.ws |language=en-US}}</ref> 

{{collapse|Global Navigation for Pilots - Read it and weep Flat-earthers|width=1200}}
{{video|youtube|bRay2R9S0GU}}
{{collapse end}}

Flat-earther's "proof" of pilots using a "flat Earth map" for navigation shows how flight paths on their map make "more sense" than some other {{wpl|map projection}}. This argument completely ignores:
# The logic (the shortest path between origin and destination) behind {{wpl|Great-circle_navigation|great-circle routes}} orbiting Earth's center (which only make sense on a globe), which e.g., the Mercator projection shows as an arc.<ref group=note>A "straight line" on a flat {{wpl|Mercator projection}} is, in fact, not the shortest path, but a path of constant bearing relative to true north, called a loxodrome (or {{wpl|Rhumb line|rhumb line}}).</ref> For long flights, this deviation from a "straight line" becomes quite notable; transcontinental flights often go near or through the polar regions, since that's the shortest route on a spherical Earth.<ref>[https://www.axismaps.com/guide/map-projections Cartography Guide - Map Projections] ''Axis Maps''.</ref><ref>Cox, J. (June 24, 2013) [https://www.usatoday.com/story/travel/columnist/cox/2013/06/24/ask-the-captain-why-dont-planes-fly-in-a-straight-line/2449729/ Ask the Captain: Why don't planes fly in a 'straight-line?']. ''USA Today''. Retrieved December 12, 2017.</ref>
# The market behind airline flights (there are fewer long-distance direct flights because they are expensive, especially in the southern hemisphere, where only 10–12% of the global population live, so there's low demand). 

The argument also backfires for flight routes in the southern hemisphere, because while a globe's latitude rings constrict approaching the pole, the flat Earth stretches them longer near the rim, thus making those routes longer than they are.<ref>{{Cite web |last=[[Professor Dave]] |first= |title=Destroying Flat Earth Without Using Science - Part 3: Airplanes |url=https://www.youtube.com/watch?v=Dd-FAyHdpxI |access-date=2023-04-02 |language=en}}</ref> 

This also applies to sailing navigation. Ships also follow such routes when they can, but of course, they have to adjust for land barriers, ocean currents and so on. All this is constant disproof of a flat Earth, since if Earth was flat these routes would be ''longer'' and take more travel time.<ref group=note>No one is stopping the flerfs from walking and measuring e.g. the east-west direction length of Australia, and proving the length is much more than the [https://www.abc.net.au/news/2022-12-28/james-mcalloon-5100-kilometre-walking-adventure-across-australia/101781452 claimed] 5,100km. People {{wpl|List_of_people_who_have_walked_across_Australia|have done that|,}} and it's not like the flerfs who aren't participating in more meaningful things in society, don't have all the time in the world.</ref> 

{{collapse|Sailing the flat Earth (be sure to watch the end)|width=1200}}
{{video|youtube|QBa40ujWt5s}}
{{collapse end}}

Of course, that's what ''[[They]]'' want you to think. The only real flat-earther responses to this are just flat-out denial or assertion that every single pilot, ship captain, and so on is part of the massive conspiracy and faking all these itineraries and end up wasting tons of fuel and mileage.<ref group=note>The meaning of "straight line" depends on the type of map. Projections involve trade-offs to preserve different features. {{wpl|Azimuthal equidistant projection}} — resembling a fish-eye lens — instead [https://flatearth.ws/ae-center shows] great circle routes as straight, but only from the center; everything else is distorted. Flat-earthers [https://flatearth.ws/azimuthal-equidistant copied the shape] of landmasses from an azimuthal equidistant map centered on the North Pole and — since they deny there's a globe to project from — deny there's any distortion.</ref>

=== "But all maps of the world are flat!" ===
[[Image:Gleason's new standard map of the world - on the projection of J. S. Christopher, Modern College, Blackheath, England; scientifically and practically correct; as "it is." (10143175716).jpg|thumb|200px|right|The "Gleason's map" created by the flat-Earther Alexander Gleason, a typical model of Earth’s surface among flatties. Despite proclaiming to show the world "as it is", Gleason admitted this map is an "extortion" of a globe (more specifically, based on the {{wpl|Azimuthal equidistant projection|azimuthal equidistant}}).<ref>https://www.reuters.com/article/fact-check/alexander-gleasons-map-of-the-world-does-not-prove-the-earth-is-flat-idUSL1N31S27S/</ref> Another simple debunk: land-masses near the “ice-wall” appear ridiculously distorted. A consequence of {{wpl|Map projection|projection}}.<ref> [https://www.youtube.com/watch?v=kIID5FDi2JQ Why all world maps are wrong] ''Vox''.</ref>]]

Like, yeah. Maps are printed on a paper. No shit. However, it is well known that all world maps are technically wrong. Why? Because all maps are a {{wpl|graphical projection}} of a three-dimensional world (a globe) into a bi-dimensional piece of paper. That lost third dimension is manifested in severe cuts and distortions. If we take the famous {{wpl|Mercator projection}} we see that Greenland is as big as Africa while the latter is around 14 times bigger than the former! Even the most common "flat Earth map" is another projection of a globe called {{wpl|Azimuthal equidistant projection}} in which it stretches along the southern hemisphere, thus making Australia twice as wide as it actually is. It also turns Antarctica into a literal ice wall. These severe distortions especially affect flight routes as mentioned before. For this reason, no world map has a unified {{wpl|scale (ratio)}} of their distances like the rest of the maps do for smaller local regions.

The fact that no accurate scaled map of the whole world exits (and can't ever exist) debunks it by itself (See also the failed {{wpl|International Map of the World}} project). In the end, cartography would be trivially easy on a flat Earth. All we would have needed to do to make a world map is to group different local maps with the same scale and stick them together. Consider for example the {{wpl|Operational Navigational Charts}}, a series of very accurate {{wpl|world aeronautical charts}} (1:1,000,000 scale) actually used for air navigation before GPS existed.<ref>[https://www.chartsandmaps.com/index.php?main_page=index&cPath=2_5 Operational Navigational Charts]</ref><ref>{{Cite web |last=Schiefer |first=Sandy |title=Library Guides: Maps and Geographic Information Systems: Air Navigation Charts |url=https://libraryguides.missouri.edu/c.php?g=28017&p=172795 |access-date=2023-04-03 |website=libraryguides.missouri.edu |language=en}}</ref> Lines of longitude flare out approaching the equator from either pole. If the charts were stitched together, as YouTuber Planarwalk did, their edges would meet to form a convex curve surface. You know. Like a globe ('''see [https://www.youtube.com/watch?v=_36-rAFWAkY&t=130s video]''').

But it is not all bad news for our flatty friends, because recently in 2021 it was published the most accurate world map called the [https://vanderbei.princeton.edu/planets_webgl/GottEarth.html "Gott Projection"], named after its inventor {{wpl|J. Richard Gott}}. Here it is:

<gallery mode="packed">
File:Gott-Goldberg-Vanderbei Projection2.jpg
</gallery >
Like a coin, it is a double-sided disk map in which each face consists of two hemispheric equidistant azimuthal projections back-to-back.
Its margin of error score is only 0.881 versus the 8.296 of the Mercator projection.<ref>{{Cite web |last=Gott |first=J. Richard |title=The Most Accurate Flat Map of Earth Yet|url=https://www.scientificamerican.com/article/the-most-accurate-flat-map-of-earth-yet/ |access-date=2025-02-20 |website=Scientific American |language=en}}</ref> In other words, the so-called "Most Accurate Flat Map of Earth Yet" implies [[Flat_Earth_debunks_-_The_Earth#.22So_why_don.27t_people_on_the_Southern_Hemisphere_fall_off.3F.22|the Earth is a disc with people walking on each face, upside down in one of them]]... oh the [[irony]].

==="But there is no North-South direction circumnavigation!"===

[https://youtu.be/N9CQPMOzeRs?si=wmxE-YnQo_21UQ_K&t=4183 Claims] Eric Dubay. {{wpl|Transglobe_Expedition|The Transglobe Expedition}} did just that in 1979-1982. 

The first circumnavigation by plane, landing at both poles was done by Dick Smith in 1988-1989, in a {{wpl|De_Havilland_Canada_DHC-6_Twin_Otter|Twin Otter|.}} There is a [https://www.amazon.com/Our-fantastic-planet-Circling-globe/dp/1862760071 book] about it, covered by Wolfie6020 [https://www.youtube.com/watch?v=fFS0hVaJ6RQ here].

==="But planes never fly through Antarctica even though it's a shorter route!"===

In his [https://youtu.be/J7RwAcL4Iq0?si=b3AmUCQ7NhWHKgCB&t=10675 video] Dubay misrepresents the problems Antarctica poses to flights, as a conspiratorial excuse of saying it's "cold". He does not consider the logistical problems of rescue missions. Should a plane make an emergency landing to Antarctica, it most likely does that because of poor weather. Saving people in up to -80°C temperatures, with strong winds increases the effect of wind chill to catastrophic levels. Locating the crashed plane in Antarctica is not trivial either, as it is [https://www.thetruesize.com/#?borders=1~!MTU4MDc5MTE.MTAxOTY4NTc*MTc0NjkxNTQ(NTk0MTU0~!CONTIGUOUS_US*MTAwMjQwNzU.MjUwMjM1MTc(MTc1)MA~!IN*NTI2NDA1MQ.Nzg2MzQyMQ)MQ~!CN*OTkyMTY5Nw.NzMxNDcwNQ(MjI1)Mg~!AQ*MTQxODkzNjg.OTg1NzcyNg(MzI4)Mw larger than the entire US].

Then there's the rescue mission. A plane that crashes into sea can be rescued by a boat. There are no runways where to land on Antarctica (outside places like the Union Glacier camp.) Helicopters like Airbus H225 have range of roughly 830 miles. That's not enough. For longer range extraction missions, the US army developed the {{wpl|Bell_Boeing_V-22_Osprey|V-22 Osprey|,}} but those are [https://news.usni.org/2024/12/09/navy-marine-v-22-ospreys-under-operational-pause-after-afsoc-incident grounded] because they seem to drop on their own due to [https://www.youtube.com/watch?v=4BmRrbxQCos design flaws] even with clear skies, let alone a whiteout with its high winds and ridiculously cold temperatures.

===There are direct flights between Australia and Southern America===

[[File:Realize nothing works in flerfia.jpg|thumb|right|250px|The flat Earth map states the distance from Sydney to Santiago is 5.3 times longer than the US is wide (2,800 miles), i.e., 14,840 miles.]]

Flat-earthers do not have an actual map with scale. Their best approximation is the {{wpl|Azimuthal_equidistant_projection|azimuthal equidistant projection}} of the globe Earth. Under this map, the distance from Santiago, Chile to Sydney, Australia is roughly 5.3 times longer than the US is wide (2,800 miles), i.e., 14,840 miles. Flat-earthers like [https://youtu.be/J7RwAcL4Iq0?si=eGtI7AOg7CW09slI&t=10622 Eric Dubay] say the route makes sense. Excluding the fact one can't see land during the direct flight, Dubay misses the point that the {{wpl|Ultra_long-haul|longest range aircraft}} is the Boeing 777-200LR with range of "only" 10,809 miles. Thus, flat-earthers claim there are no direct flights from Australia to South America (or that Boeing is deliberately ''under''stating the range of their aircraft, which would be a very unusual thing for an aircraft manufacturer to do).

Dubay also [https://youtu.be/J7RwAcL4Iq0?si=LK8x3Vmif0a-vQUa&t=10949 claimed] long haul planes can hide the distance they cover by traveling much faster than the advertised speed, especially during long haul flights. This idea runs into a tiny hurdle known as laws of physics. {{wpl|Drag_(physics)#The_drag_equation|Air resistance}} increases as a square of the headwind. Going twice as fast would cut flight time in half, but it would also burn four times the fuel, cutting the haul distance by 50%.

{{collapse|Flights in the Southern Hemisphere List|width=500}}
<gallery mode="packed" heights="750">
File:Flights in the Southern Hemisphere.jpeg|Southern Hemisphere Long Haul flights list (many impossible on a flat Earth, even if they were twice faster).
</gallery>
{{collapse end}}

As seen [https://www.flightsfrom.com/explorer/SCL?mapview here], there are direct flights. If you need convincing, here's a full 11 hour 42 minute flight video from Sydney, Australia to Santiago, Chile.

{{collapse|QF27 Sydney-Santiago Full Video|width=500}}
<center>{{#ev:youtube|Mmr1udYympc|||||start=254}}</center>
{{collapse end}}

Flat-earther Jeranism [https://www.youtube.com/watch?v=QDbTtjcTKd8 tried] to explain Sydney to Santiago route was possible with the southern {{wpl|Jet_stream|jet stream|,}} however, as Dave Farina [https://youtu.be/Dd-FAyHdpxI?feature=shared&t=209 points out], the jet stream does not solve the planes being able to cover the distance in both directions. There is some effect from the wind, in that the flight time from Sydney to Santiago is 12h 35 min, and from Santiago to Sydney is 14h 40 min. But that's again, not enough time to cover the almost 15,000 mile route, let alone the conspiracy-hiding route across the Pacific Ocean.

Thus, these flights can only be explained if the Earth is a globe: In the globe model, the distance from Santiago's airport to the one in Sydney, is just 7060.3 miles.

== See also ==
* [[Flat_Earth|Flat Earth]]

Flat Earth Debunks

* '''[[Flat_Earth_debunks_-_The_Moon|The Moon]]'''
* [[Flat_Earth_debunks_-_The_Sun|The Sun]]
* [[Flat_Earth_debunks_-_Stars|Stars]]
* [[Flat_Earth_debunks_-_Celestial_mechanics|Celestial mechanics]]
* [[Flat_Earth_debunks_-_Celestial_objects|Celestial objects]]
* [[Flat_Earth_debunks_-_Astronautics|Astronautics]]
* [[Flat_Earth_debunks_-_Astrophotography|Astrophotography]]
* [[Flat_Earth_debunks_-_The_conspiracy|The conspiracy]]

==Notes==
{{reflist|group=note}}

==References==
{{reflist|2|80%}}

[[Category:Anti-intellectualism]]
[[Category:Conspiracy theories]]
[[Category:Denialism]]
[[Category:Silly "Earth" theories]]
[[Category:Flat Earth]]
[[Category:Pseudoscience]]
[[Category:Pseudoastronomy]]

Categories: Anti-intellectualism, Conspiracy theories, Denialism, Silly "Earth" theories, Flat Earth, Pseudoscience, Pseudoastronomy