Refutation: 200 Flat Earth Proofs by Eric Dubay

I've been meaning to tackle Dubay's '200 Proofs' Gish Gallop for a while but it's rather long and repetitious and most of it is already covered on my Blog in more interesting ways. But I thought it might be fun and useful to create a kind of taxonomy of Flat Earth failures from it, so that is my primary goal.

It's also interesting to see that a lot of them are just copy & pasted from "Earth Not A Globe" and many others are from other sources -- I begin to doubt that Dubay came up with a single one of these himself.

Here is the video version of Dubay's '200 proofs' (NOTE: Dubay got himself delete for hate speech so I'm now linking to a mirror [original]):

Before I get started, when you see someone claiming 'Proof' you should immediately be wary because science doesn't deal in proofs. Proof is done in a formal way in mathematics and there is a colloquial sense of 'proof' where the evidence supports the conclusion - but whenever someone says they have 'proved' something they are usually wrong and are being misleading either out of ignorance or malice (as we will see over and over and over again as Dubay's "proof" fails 200 times in a row).

In science, all conclusions are tenuous and contingent on future evidence. The highest ideal in science is a Scientific Theory -- these are built on a vast array of evidence and explain an observable phenomena rather than merely measure it.

Next is a Scientific Law, which is based on repeatable measurements where all known variance is accounted for (but even Laws can change, Newton's Law of Gravity gave way in light of measurements under extreme conditions and now support Relativity). All Laws come with error bars and a bounding box under which they have been tested, more accurate measurements or measurements outside the realm in which the Law is known to hold can show deviations and lead to new Laws. But the new Law has to be compatible with the old Law -- under normal, everyday conditions without going to extremes of measurement, Relativity simplifies to Newtonian physics. And we still use Newton's equations.

A Scientific Theory does not become a Scientific Law -- these are in entirely different categories.

Nothing in science is sacred -- not even the shape of the Earth. If someone can prove that all of science has it wrong by a repeatable observation that isn't accounted for by known and demonstrable phenomena then fine -- the Earth can be Flat for all I care. What matters is the evidence you bring to the table...

And despite these multiple hour long diatribes no Flat Earther has ever shown even a single bit of evidence that contradicts the Heliocentric/Globe model or shows a violation of accepted physics.

Not Once.

This is why the proponents of Flat Earth are relegated to the dark corners of social media with most people pointing and laughing.

Other Dubay debunkings:

200 Proofs debunked (video), in 28 minutes
http://200proofsearthisnotflat.blogspot.com/
http://roundearthsense.blogspot.com/

So, here we go... 200 PROOFS!

1) The horizon always appears perfectly flat 360 degrees around the observer regardless of altitude. All amateur balloon, rocket, plane and drone footage show a completely flat horizon over 20+ miles high. Only NASA and other government “space agencies” show curvature in their fake CGI photos/videos.

Taxonomy: Horizon Geometry, Unevidenced Assertion

This debunks itself -- a truly flat horizon would, as Dubay's false images suggest, extend infinitely off left and right and could simply not curve around you 360°. But even Dubay says it's "360 degrees around the observer"! HINT.

The reason that the Horizon curvature, which curves around you, "looks flat" is because you are viewing it on edge. Dubay and other Flat Earthers do not actually understand the geometry of a Horizon on a Spheroid. See: Flat Earth Faux Pas : What Is The Horizon?

I'll unpack this in more detail here since this claim is really their linchpin.

The horizon is the green circle in this image -- this is formed where the observer line-of-sight falls tangent to the sphere:

In this example the viewer would be thousands of miles up. Below is what this looks like to someone 35k feet up in an airplane. That angle is still only around 3° and you're looking at a circle 229 miles away -- and you can still see only a very tiny portion of Earths' surface. You do not see the 'limbs of the Earth' here -- the Earth is not expected to curve downwards, the horizon curves around the observer. This is a simple fact of spheroids.

Walter Bislin has an incredible horizon rendering tool you should check out. It will, given altitude, field of view, and other parameters show you what you should see. From 10 km (32k feet) you might see something like this using a 50mm lens:

That's going to "look flat" to just about anyone, especially with atmospheric haze making a sharp horizon unlikely at that distance. See that Eye-Level marker? We can measure that drop... The green reticle in the image below marks out level from my position using a Theodolite app on my phone also. I'm a bit higher, 38,800 feet so the angle to the horizon is about 3.4°.

See: Flat Earth Follies: The Horizon Always Rises To Eye Level

As for his claim "All amateur balloon, rocket, plane and drone footage show a completely flat horizon over 20+ miles high." I don't even see how he can state that with a straight face since it is objectively, factually incorrect.

I get that a lot of balloon footage uses curvilinear (fish-eye) lenses and that Flat Earthers cannot think past "CURVE BAD! PICK FLAT FRAME" but we've shown over and over and over that a fish-eye lens compresses the visual field such that everything is bowed away from center (or pulled in from the edges). So any image where the curvature is convex that is bowing towards center of lens proves Earth's curvature. Ideally the horizon peak is just touching center of the lens and then all distortion is minimized.

I've also shown this in my analysis of the Rotaflight Balloon footage in an additional way -- we can see the curvature growing with altitude when we place the horizon in the same place (peak dead center of lens). This rules out the lens as the cause of curvature.

and up

And we can simply de-fish the images (I recommend GIMP) -- notice how this (slightly) increases the horizon curvature? This is because the fisheye effect had squished our edges upwards reducing the apparent curvature.

One of the many ways Flat Earthers use these types of images to misrepresent reality, is that they either cherry pick a frame where the horizon is outside lens center (and thus it looks fairly flat) or they apply ridiculous amounts of lens correction until it looks flat and then crop off the horribly distorted portions -- they don't ever tell you why the horizon needs to pass through the center or apply the correct fisheye correction:

But we can even see this in Rob Skiba's own balloon video shows curvature exactly as we expect it to -- even when his lower camera is non-fisheye. We will see more examples as we go.

Finally, "Only NASA and other government “space agencies” show curvature in their fake CGI photos/videos." is just an assertion. Flat Earthers cannot demonstrate this. They like to point to images where NASA themselves told everyone how they were made by modeling satellite data as fakes but I'm sorry -- where NASA has told you how they created the images it's not a fake, it's not a fraud, it's not evidence of a conspiracy... it's simply an image they were excited to create from low-earth orbit satellite data at a time when we did not have full frame, color image cameras to give us similar images of the Earth. We have those nows in the form of DSCOVR:EPIC, Himawari-8, Himawari-9, and now GOES-16 as well.

So basically nothing Dubay says in point #1 is true. If we're being generous he is seriously confused and his bias is leading him to false conclusions.

2) The horizon always rises to the eye level of the observer as altitude is gained, so you never have to look down to see it. If Earth were in fact a globe, no matter how large, as you ascended the horizon would stay fixed and the observer / camera would have to tilt looking down further and further to see it.

Taxonomy: Horizon Geometry, Horizon Rises to Eye-Level

The horizon does not "rise to eye-level", this claim is refuted here: Flat Earth Follies: The Horizon Always Rises To Eye Level

There is nothing in the images given that proves that Dubay's red line marks out level from the observer.

The Dogcam footage also very clearly shows curvature and since Dubay is appealing to this footage as PROOF I assume he will accept that the Earth is curved based on this same footage?

Of course, I didn't fake my evidence, this is a screenshot straight from the video and it very clearly shows a curved horizon.

I've also done a deep dive on this footage and added a lot of detail about these shots.

See: Analysis: Dogcam footage - Does the "hotspot" proves a Flat Earth?

3) The natural physics of water is to find and maintain its level. If Earth were a giant sphere tilted, wobbling and hurdling through infinite space then truly flat, consistently level surfaces would not exist here. But since Earth is in fact an extended flat plane, this fundamental physical property of fluids finding and remaining level is consistent with experience and common sense.

Taxonomy: Level

According to the Earth Science of Geodesy 'Level' is defined as perpendicular to Plumb, and Plumb simply follows Gravity which wobbles a bit due to the density of the Earth not being uniform.

Scale is exaggerated
Image credit: NOAA: Datums, Heights, and Geodesy

Nor according to simple observation where water is perfectly happy to form a spheroid.

Rotating Sphere of Water in Microgravity

Water doesn't 'SEEK' anything, what happens is, it is affected by the forces of Nature like every other object and those forces can cause it to conform to any shape and we see the impact of Wind, and Tides on our oceans as well.

Dubay here never shows you how to calculate the effect size of any spinning or other forces, he just makes assertions appealing to false 'common sense' hoping you don't know how it actually works.

See: Flat Earth Follies: But you would fly off the Earth due to spinning
See: Water Finds Its Level - Ocean surface topography reveals ocean floor topography
See: Soundly Shows Flat Earthers The Curve

4) Rivers run down to sea-level finding the easiest course, North, South, East, West and all other intermediary directions over the Earth at the same time. If Earth were truly a spinning ball then many of these rivers would be impossibly flowing uphill, for example the Mississippi in its 3000 miles would have to ascend 11 miles before reaching the Gulf of Mexico.

Taxonomy: Gravity

You are going to see this one a lot.

Dubay has lied to you about how Gravity works. Under the influence of Gravity, 'down' is simply towards the center of the Earth -- it has nothing to do with North, South, East, or West.

And we know Gravity exists because #1 things Fall, #2 even things of different mass fall at the same rate, #3 this rate matches F=GMm/r² which gives us F=m * g (where g is ~9.8m/s² around the surface of the Earth), #4 gravity cannot be shielded, #5 gravity accelerates mass without registering on an accelerometer -- unlike every other force.

See: Flat Earth Follies: Blowing Gravity Out Of The Water!
See: Flat Earth Follies: 10 Point Flat Earth Meme "Not a Spinning Ball"
See: How Compton computed Latitude, direction to North, and length of a day

5) One portion of the Nile River flows for a thousand miles with a fall of only one foot. Parts of the West African Congo, according to the supposed inclination and movement of the ball-Earth, would be sometimes running uphill and sometimes down. This would also be the case for the Parana, Paraguay and other long rivers

Taxonomy: Gravity

Duplicate of #4

6) If Earth were a ball 25,000 miles in circumference as NASA and modern astronomy claim, spherical trigonometry dictates the surface of all standing water must curve downward an easily measurable 8 inches per mile multiplied by the square of the distance. This means along a 6 mile channel of standing water, the Earth would dip 6 feet on either end from the central peak. Every time such experiments have been conducted, however, standing water has proven to be perfectly level.

Taxonomy: Level

Dubay has his facts completely reversed here, every measurement shows Earth curvature and he just wants to distort those facts.

This 8" x miles^2 equation is, in fact, only an estimate that works for shorter distances. You can trivially see that this equation is a parabola and not a circular curve so that should clue you in.

But the most egregious error using this formula is that it does not account for observer height so it does not tell you how much of some distant object is hidden by the horizon. Even a trivial diagram shows that an elevated observer can see further over a spheroid.

And second most egregious is that it ignores refraction which can be hugely variable, as shown here:

From Joshua Nowicki YouTube Video

The most famous of this being debunked is when Wallace proved the Earth curvature at the Old Bedford Level where Samuel Birley Rowbotham himself had supposedly "proved the flatness" by failing to account for refraction (despite clearly quoting from Britannica talking about refraction in his book!)

See: Old Bedford Level

Here is some standing water

See: Soundly Shows Flat Earthers The Curve

7) Surveyors, engineers and architects are never required to factor the supposed curvature of the Earth into their projects. Canals, railways, bridges and tunnels for example are always cut and laid horizontally, often over hundreds of miles without any allowance for curvature.

Taxonomy: Earth Curvature, Unevidenced Assertion

It's just that many civil engineering projects, even over long distances, do not need to directly calculate or care about Earth curvature. If you measure 150 miles in Google Earth as the distance and you buy material for 150 miles of track then you have already accounted for curvature. The survey distance already accounts for curvature. The engineering team doesn't need to DO anything else.

However, some engineering projects are well documented as being required to take Earth curvature into account (building SLAC and LIGO projects are example).

For an example, I'll share this little Flat Earth lie, as it contradicts Dubay too.

8) The Suez Canal connecting the Mediterranean with the Red Sea is 100 miles long without any locks making the water an uninterrupted continuation of the two seas. When constructed, the Earth’s supposed curvature was not taken into account, it was dug along a horizontal datum line 26 feet below sea-level, passing through several lakes from one sea to the other, with the datum line and water’s surface running perfectly parallel over the 100 miles.

Taxonomy: Earth Curvature, Level, Unevidenced Assertion

Duplicate claim -- sea-level is expected to be nearly constant around a Globe, varying only with the local gravity and that is exactly what we find.

Go look at the survey data, it will be curved.

9) Engineer, W. Winckler was published in the Earth Review regarding the Earth’s supposed curvature, stating, “As an engineer of many years standing, I saw that this absurd allowance is only permitted in school books. No engineer would dream of allowing anything of the kind. I have projected many miles of railways and many more of canals and the allowance has not even been thought of, much less allowed for. This allowance for curvature means this - that it is 8” for the first mile of a canal, and increasing at the ratio by the square of the distance in miles; thus a small navigable canal for boats, say 30 miles long, will have, by the above rule an allowance for curvature of 600 feet. Think of that and then please credit engineers as not being quite such fools. Nothing of the sort is allowed. We no more think of allowing 600 feet for a line of 30 miles of railway or canal, than of wasting our time trying to square the circle”

Taxonomy: Earth Curvature, Unevidenced Assertion

What kind of engineer doesn't understand that adding distance dropping down from a tangent would not be the same as the additional distance for curvature? That's obviously two very different things:

Furthermore, If you've already measured the distance as 30 miles then it's 30 miles, you don't need to add anything additional for curvature, you already measured it.

10) The London and Northwestern Railway forms a straight line 180 miles long between London and Liverpool. The railroad’s highest point, midway at Birmingham station, is only 240 feet above sea-level. If the world were actually a globe, however, curving 8 inches per mile squared, the 180 mile stretch of rail would form an arc with the center point at Birmingham raising over a mile, a full 5,400 feet above London and Liverpool.

Taxonomy: Level

Duplicate claim. Nope, it would curve along with the surface of the curved water and above and below mean relative to the curved Earth Geoid.

11) A surveyor and engineer of thirty years published in the Birmingham Weekly Mercury stated, “I am thoroughly acquainted with the theory and practice of civil engineering. However bigoted some of our professors may be in the theory of surveying according to the prescribed rules, yet it is well known amongst us that such theoretical measurements are INCAPABLE OF ANY PRACTICAL ILLUSTRATION. All our locomotives are designed to run on what may be regarded as TRUE LEVELS or FLATS. There are, of course, partial inclines or gradients here and there, but they are always accurately defined and must be carefully traversed. But anything approaching to eight inches in the mile, increasing as the square of the distance, COULD NOT BE WORKED BY ANY ENGINE THAT WAS EVER YET CONSTRUCTED. Taking one station with another all over England and Scotland, it may be stated that all the platforms are ON THE SAME RELATIVE LEVEL. The distance between Eastern and Western coasts of England may be set down as 300 miles. If the prescribed curvature was indeed as represented, the central stations at Rugby or Warwick ought to be close upon three miles higher than a chord drawn from the two extremities. If such was the case there is not a driver or stoker within the Kingdom that would be found to take charge of the train. We can only laugh at those of your readers who seriously give us credit for such venturesome exploits, as running trains round spherical curves. Horizontal curves on levels are dangerous enough, vertical curves would be a thousand times worse, and with our rolling stock constructed as at present physically impossible.”

Taxonomy: Level

Duplicate. Once again, up and down are relative to gravity and, in fact, define level.

As you follow the curvature of the Earth you are going neither up nor down.

Up is when you get further from the center of the Earth and down is when you get closer to the center of the Earth.

Also an obvious fabrication as trains go up and down hills all the time. Tracks are not level or straight and vary much greater than the Earth's curvature.

12) The Manchester Ship Canal Company published in the Earth Review stated, “It is customary in Railway and Canal constructions for all levels to be referred to a datum which is nominally horizontal and is so shown on all sections. It is not the practice in laying out Public Works to make allowances for the curvature of the earth

Taxonomy: Level

I can only find this 'source' in Flat Earth circles but that is irrelevant as it contains its own undoing - "nominally" means "in name only; officially though perhaps not in reality". It means they can mostly ignore the effects of curvature for whatever scale of work they are doing and treat it AS IF it is horizontal.

The WGS 84 datum surface is, in fact, an oblate spheroid (ellipsoid). Distances are already computed with this curvature - so you don't need to 'make allowances' for curvature when such allowances are already made in the datum you are using.

13) In a 19th century French experiment by M. M. Biot and Arago a powerful lamp with good reflectors was placed on the summit of Desierto las Palmas in Spain and able to be seen all the way from Camprey on the Island of Iviza. Since the elevation of the two points were identical and the distance between covered nearly 100 miles, if Earth were a ball 25,000 miles in circumference, the light should have been more than 6600 feet, a mile and a quarter, below the line of sight!

Taxonomy: Earth Curvature, Unevidenced Assertion

Confuses the curvature drop, which doesn't take into account observer height, with estimates of what we could see at some distance (which must include observer height). Also ignores the fact that due to scattering in the atmosphere, lights can be seen much further away than you can see the light source itself.

At what elevation was this observation made? He left that out. How high was the light? He left that out. How was it verified that we're seeing the actual light and not simply scattering of the light? He left that out.

At 1900 feet your horizon is about 53 miles away -- if both parties are at 1900 feet and 100 miles apart they would be expected to be able to see each other. If one is a little higher the other can be a little lower.

Can Dubay (or anyone) show me the detailed evidence supporting this claim?

14) The Lieutenant-Colonel Portlock experiment used oxy-hydrogen Drummond’s lights and heliostats to reflect the sun’s rays across stations set up across 108 miles of St. George’s Channel. If the Earth were actually a ball 25,000 miles in circumference, Portlock’s light should have remained hidden under a mile and a half of curvature.

Taxonomy: Earth Curvature, Unevidenced Assertion

Duplicate of #13.

15) If the Earth were truly a sphere 25,000 miles in circumference, airplane pilots would have to constantly correct their altitudes downwards so as to not fly straight off into “outer space;” a pilot wishing to simply maintain their altitude at a typical cruising speed of 500 mph, would have to constantly dip their nose downwards and descend 2,777 feet (over half a mile) every minute! Otherwise, without compensation, in one hour’s time the pilot would find themselves 31.5 miles higher than expected.

Taxonomy: Earth Curvature

Actually they simply adjust their elevator trim for zero vertical speed and this automatically causes the plane to rotate to compensate for the curvature of the Earth.

See: Flat Earth Follies: Planes would have to constantly pitch down to fly!

16) The experiment known as “Airy’s Failure” proved that the stars move relative to a stationary Earth and not the other way around. By first filling a telescope with water to slow down the speed of light inside, then calculating the tilt necessary to get the starlight directly down the tube, Airy failed to prove the heliocentric theory since the starlight was already coming in the correct angle with no change necessary, and instead proved the geocentric model correct.

Taxonomy: Earth Rotation

Complete misrepresentation of Airy's experiment and the implications. What Airy, and Michelson-Morley, showed was there is no aether that we are moving through.

Michelson-Gale-Pearson, Sagnac, Compton, et al. proved Earth's motion around the Sun and Rotation about an axis. The observed annual stellar aberration, or apparent motion of celestial objects about their true positions, is dependent on the velocity of the observer which also proves the Earth is moving. What finally accounted for all observations is Einstein's Relativity.

17) “Olber’s Paradox” states that if there were billions of stars which are suns the night sky would be filled completely with light. As Edgar Allen Poe said, “Were the succession of stars endless, then the background of the sky would present us a uniform luminosity, since there could exist absolutely no point, in all that background, at which would not exist a star.” In fact Olber’s “Paradox” is no more a paradox than George Airy’s experiment was a “failure.” Both are actually excellent refutations of the heliocentric spinning ball model.

Taxonomy: Stellar Brightness

All this 'proves' is that there aren't infinitely many evenly distributed stars.

18) The Michelson-Morley and Sagnac experiments attempted to measure the change in speed of light due to Earth’s assumed motion through space. After measuring in every possible different direction in various locations they failed to detect any significant change whatsoever, again proving the stationary geocentric model.

Taxonomy: Earth Rotation

Duplicate of #16

19) Tycho Brahe famously argued against the heliocentric theory in his time, positing that if the Earth revolved around the Sun, the change in relative position of the stars after 6 months orbital motion could not fail to be seen. He argued that the stars should seem to separate as we approach and come together as we recede. In actual fact, however, after 190,000,000 miles of supposed orbit around the Sun, not a single inch of parallax can be detected in the stars, proving we have not moved at all.

Taxonomy: Angular Physics Strawman, Factual Error

This one is hilarious because parallax isn't measured in inches -- it is an angular measurement in degrees or radians. Did Dubay tell you how to find the expected shift in position given some distance moved? It is: (2*arctan(size/2/distance)). We defined the Parsec unit based on this in fact. A parallax angle of 1 arc second at a size of 1 AU.

This might look fancy but this is just based on a simple slope calculation, or RISE (1/2 the total size) over RUN (the distance), which gives us our half-angle, which we double to get the total angular size. This is one-in-the-same as the law of Perspective:

You'll see me use 2*arctan(size/2/distance) several times throughout my rebuttal so it would be good to spend some time to understand how and why this works. There is also a handy angular diameter calculator. One caution is that you need to find the 'size' that is perpendicular to your line of vision, it's not always the simple height of the object. You'll see in one case I compensate for the small 'tilt' of the object, but we show that it's insignificant.

That gives us 1" = 2*arctan(1au/2/distance) -- so we can solve for distance = 1au/(2*tan(1"/2)) and find that our distance is ~206264.8 AU or ~3.26 light years away -- this is 1 Parsec, aka, the distance at which a 1 au shift gives a parallax angle of 1 arc second (1").

The Hipparcos mission has measured the annular parallax of over 120,000 stars to 1/1000th of an arcsecond.

Stars also move around aside from parallax. This claim is just complete fabrication on Dubay's part.

This also ignores that we're moving around the galaxy with those nearby stars so our relative motion is not nearly the same as our speed around the galaxy, etc.

20) If Earth were truly constantly spinning Eastwards at over 1000mph, vertically-fired cannonballs and other projectiles should fall significantly due west. In actual fact, however, whenever this has been tested, vertically-fired cannonballs shoot upwards an average of 14 seconds ascending, 14 seconds descending, and fall back to the ground no more than 2 feet away from the cannon, often directly back into the muzzle.

Taxonomy: Earth Rotation

Utter Nonsense, a cannonball does not magically lose its rotational momentum simply because you fire it upwards. The deflection of about inches is exactly what you would expect, and 2 feet is likely due to wind. Show me your math...

From Galilean Relativity we know that this claim is false.

21) If the Earth were truly constantly spinning Eastwards at over 1000mph, helicopters and hot-air balloons should be able to simply hover over the surface of the Earth and wait for their destinations to come to them!

Taxonomy: Earth Rotation

Helicopters (which require constant and furious stick inputs to hover) and Balloons also do not lose their existing rotational momentum just because they are in the air.

Duplicate of #20

22) If Earth were truly constantly spinning Eastwards at over 1000mph, during the Red Bull stratosphere dive, Felix Baumgartner, spending 3 hours ascending over New Mexico, should have landed 2500 miles West into the Pacific Ocean but instead landed a few dozen miles East of the take-off point.

Taxonomy: Earth Rotation

Balloons and falling men do not lose their existing rotational momentum just because they are in the air.

Duplicate of #20

Which makes the claim of *200* proofs extremely dubious.

23) Ball-believers often claim “gravity” magically and inexplicably drags the entire lower-atmosphere of the Earth in perfect synchronization up to some undetermined height where this progressively faster spinning atmosphere gives way to the non-spinning, non-gravitized, non-atmosphere of infinite vacuum space. Such non-sensical theories are debunked, however, by rain, fireworks, birds, bugs, clouds, smoke, planes and projectiles all of which would behave very differently if both the ball-Earth and its atmosphere were constantly spinning Eastwards at 1000mph.

Taxonomy: Earth Rotation

No Dubay, it's not 'gravity' -- it's well-documented fluid dynamics that causes the air to mostly rotate with the Earth. Deviations from matching that rotation are called Wind. Same goes all the way up. And you failed to calculate how much faster it would be spinning and show that this effect-size cannot be accounted for with existing fluid dynamic models.

See: Flat Earth Follies: vacuum of space would suck the atmosphere off the Earth

Rain, fireworks, birds, bugs, clouds, smoke, planes and projectiles do not lose their existing rotational momentum just because they are in the air.

Duplicate of #20

24) If Earth and its atmosphere were constantly spinning eastwards over 1000mph then North/South facing cannons should establish a control while East-firing cannonballs should fall significantly farther than all others while West-firing cannonballs should fall significantly closer. In actual fact, however, regardless of which direction cannons are fired, the distance covered is always the same.

Taxonomy: Rotational Physics Strawman, Factual Error

See: Flat Earth Follies: Military Ballistics doesn't take Earth Curvature into Account

25) If Earth and its atmosphere were constantly spinning eastwards over 1000mph, then the average commercial airliner traveling 500mph should never be able to reach its Eastward destinations before they come speeding up from behind! Likewise Westward destinations should be arrived at thrice the speed, but this is not the case.

Taxonomy: Rotational Physics Strawman

Once again, airplanes also do not lose their existing rotational momentum just because they are in the air.

Duplicate of #20

26) Quoting “Heaven and Earth” by Gabrielle Henriet, “If flying had been invented at the time of Copernicus, there is no doubt that he would have soon realized that his contention regarding the rotation of the earth was wrong, on account of the relation existing between the speed of an aircraft and that of the earth’s rotation. If the earth rotates, as it is said, at 1,000 miles an hour, and a plane flies in the same direction at only 500 miles, it is obvious that its place of destination will be farther removed every minute. On the other hand, if flying took place in the direction opposite to that of the rotation, a distance of 1,500 miles would be covered in one hour, instead of 500, since the speed of the rotation is to be added to that of the plane. It could also be pointed out that such a flying speed of 1,000 miles an hour, which is supposed to be that of the earth’s rotation, has recently been achieved, so that an aircraft flying at this rate in the same direction as that of the rotation could not cover any ground at all. It would remain suspended in mid-air over the spot from which it took off, since both speeds are equal.”

Taxonomy: Rotational Physics Strawman

Once again, airplanes also do not lose their existing rotational momentum just because they are in the air.

Duplicate of #20

Seriously dude. Newton's Laws -- Physics 101 level stuff.

27) If Earth and its atmosphere were constantly spinning Eastwards over 1000mph, landing airplanes on such fast-moving runways which face all manner of directions North, South, East, West and otherwise would be practically impossible, yet in reality such fictional concerns are completely negligible.

Taxonomy: Rotational Physics Strawman

Once again, airplanes also do not lose their existing rotational momentum just because they are in the air.

Duplicate of #20

28) If the Earth and its atmosphere were constantly spinning Eastwards over 1000mph, then clouds, wind and weather patterns could not casually and unpredictably go every which way, with clouds often travelling in opposing directions at varying altitudes simultaneously.

Taxonomy: Rotational Physics Strawman

Once again, air molecules also do not lose their existing rotational momentum.

Duplicate of #20

29) If the Earth and its atmosphere were constantly spinning Eastwards over 1000mph, this should somewhere somehow be seen, heard, felt or measured by someone, yet no one in history has ever experienced this alleged Eastward motion; meanwhile, however, we can hear, feel and experimentally measure even the slightest Westward breeze.

Taxonomy: Rotational Physics Strawman

Once again, air molecules also do not lose their existing rotational momentum.

Duplicate of #20

And I'll add here that You Cannot Locally Measure Speed. You can measure acceleration. You can measure your speed relative to something else. But there is NO instrument that can say "you are going 20 mph". It's always relative to something else.

In a car, your speedometer measures the rotation of the axle -- it literally counts how many times it goes around per unit time and guesses a speed based on that given the standard tire size for that vehicle. Change your tire size and it will read out incorrectly.

People on the Concorde going 1341 mph could walk up and the down aisles freely because you do not feel speed. They could juggle, pour water, stand, walk, all with no problem. The only time it's a problem is when it isn't smooth because that causes many sharp accelerations in all directions.

We can also measure relative speed with the doppler effect, by seeing how frequencies of sound or light are shifted by speed.

30) In his book “South Sea Voyages,” Arctic and Antarctic explorer Sir James Clarke Ross, described his experience on the night of November 27th, 1839 and his conclusion that the Earth must be motionless: “The sky being very clear … it enabled us to observe the higher stratum of clouds to be moving in an exactly opposite direction to that of the wind--a circumstance which is frequently recorded in our meteorological journal both in the north-east and south-east trades, and has also often been observed by former voyagers. Captain Basil Hall witnessed it from the summit of the Peak of Teneriffe; and Count Strzelechi, on ascending the volcanic mountain of Kiranea, in Owhyhee, reached at 4000 feet an elevation above that of the trade wind, and experienced the influence of an opposite current of air of a different hygrometric and thermometric condition … Count Strzelechi further informed me of the following seemingly anomalous circumstance--that at the height of 6000 feet he found the current of air blowing at right angles to both the lower strata, also of a different hygrometric and thermometric condition, but warmer than the inter-stratum. Such a state of the atmosphere is compatible only with the fact which other evidence has demonstrated, that the earth is at rest."

Taxonomy: Rotational Physics Strawman

Once again, air molecules also do not lose their existing rotational momentum.

They are therefore subject freely to fluid dynamics -- pressure changes caused by heating and cooling, and all the rest. Having wind going different directions on a rotating Earth is not a violation of any physical law.

Duplicate of #20

31) Quoting “Zetetic Cosmogeny” Thomas Winships states: “Let ‘imagination’ picture to the mind what force air would have which was set in motion by a spherical body of 8,000 miles in diameter, which in one hour was spinning round 1,000 mph, rushing through space at 65,000 mph and gyrating across the heavens? Then let ‘conjecture’ endeavor to discover whether the inhabitants on such a globe could keep their hair on? If the earth-globe rotates on its axis at the terrific rate of 1,000 miles an hour, such an immense mass would of necessity cause a tremendous rush of wind in the space it occupied. The wind would go all one way, and anything like clouds which got ‘within the sphere of influence’ of the rotating sphere, would have to go the same way. The fact that the earth is at rest is proved by kite flying.”

Taxonomy: Rotational Physics Strawman

Duplicate of #20

32) If “gravity” is credited with being a force strong enough to hold the world’s oceans, buildings, people and atmosphere stuck to the surface of a rapidly spinning ball, then it is impossible for “gravity” to also simultaneously be weak enough to allow little birds, bugs, and planes to take-off and travel freely unabated in any direction.

Taxonomy: Physics Strawman

Except The FORCE of Gravity is F=ma -- mass TIMES the acceleration of gravity (9.8m/s²) -- non-rigid bodies do not share a force of gravity -- but as a first approximation a rigid body can be treated as one mass.

The FORCE felt by each water molecule is very small, the force on an insect is miniscule.

The electro-chemical energy used by the insect is more than sufficient to overcome the force of gravity.

Dubay must somehow think the FORCE is constant for all independent masses, which is just wrong.

33) If “gravity” is credited with being a force strong enough to curve the massive expanse of oceans around a globular Earth, it would be impossible for fish and other creatures to swim through such forcefully held water.

Taxonomy: Physics Strawman

Literally nobody says that... duplicate of #32

34) Ship captains in navigating great distances at sea never need to factor the supposed curvature of the Earth into their calculations. Both Plane Sailing and Great Circle Sailing, the most popular navigation methods, use plane, not spherical trigonometry, making all mathematical calculations on the assumption that the Earth is perfectly flat. If the Earth were in fact a sphere, such an errant assumption would lead to constant glaring inaccuracies. Plane Sailing has worked perfectly fine in both theory and practice for thousands of years, however, and plane trigonometry has time and again proven more accurate than spherical trigonometry in determining distances across the oceans.

Taxonomy: Factual Error

The nautical mile is defined as 1 arc minute of curvature of the Earth by measuring the angle of stars like Polaris to find your latitude. This is the only way long distance voyages were successfully navigated.

"Plane Sailing" is only for very short distances and the resulting Rhumb lines (of constant bearing) are demonstrably longer distances than the Great Circle routes necessary for efficient long distance voyages. In fact, Rhumb lines actually spiral around towards the poles:

NO long distance commercial vessel today uses "Plane Sailing".

35) If the Earth were truly a globe, then every line of latitude south of the equator would have to measure a gradually smaller and smaller circumference the farther South travelled. If, however, the Earth is an extended plane, then every line of latitude south of the equator should measure a gradually larger and larger circumference the farther South travelled. The fact that many captains navigating south of the equator assuming the globular theory have found themselves drastically out of reckoning, moreso the farther South travelled, testifies to the fact that the Earth is not a ball.

Taxonomy: Factual Error

Latitude circles DO get smaller and smaller as you travel South.

Do you see planes banking over to fly around the Equator?

And in fact, even the simple geometry of a flat plane circle will not match the Flat Earth model cited:

36) During Captain James Clark Ross’s voyages around the Antarctic circumference, he often wrote in his journal perplexed at how they routinely found themselves out of accordance with their charts, stating that they found themselves an average of 12-16 miles outside their reckoning every day, later on further south as much as 29 miles.

Taxonomy: Appeal to Incompetence

Yes? And? This isn't a proof of anything except their incompetence. Maybe they foolishly believed the world to be flat?

37) Lieutenant Charles Wilkes commanded a United States Navy exploration expedition to the Antarctic from 1838 to 1842, and in his journals also mentioned being consistently east of his reckoning, sometimes over 20 miles in less than 18 hours.

Taxonomy: Appeal to Incompetence

Yes? And?

(this is mind-numbing...)

38) To quote Reverend Thomas Milner, “In the southern hemisphere, navigators to India have often fancied themselves east of the Cape when still west, and have been driven ashore on the African coast, which, according to their reckoning, lay behind them. This misfortune happened to a fine frigate, the Challenger, in 1845. How came Her Majesty’s Ship ‘Conqueror,’ to be lost? How have so many other noble vessels, perfectly sound, perfectly manned, perfectly navigated, been wrecked in calm weather, not only in dark night, or in a fog, but in broad daylight and sunshine - in the former case upon the coasts, in the latter, upon sunken rocks - from being ‘out of reckoning?’” The simple answer is that Earth is not a ball.

Taxonomy: Appeal to Incompetence

Yes? And?

39) Practical distance measurements taken from “The Australian Handbook, Almanack, Shippers’ and Importers’ Directory” state that the straight line distance between Sydney and Nelson is 1550 statute miles. Their given difference in longitude is 22 degrees 2’14”. Therefore if 22 degrees 2’14” out of 360 is 1550 miles, the entirety would measure 25,182 miles. This is not only larger than the ball-Earth is said to be at the equator, but a whole 4262 miles greater than it would be at Sydney’s southern latitude on a globe of said proportions.

Taxonomy: Latitude/Longitude Strawman

Nelson, NZ is closer to 1310 statute miles, this is 18.9° because you cannot just difference the longitude -- that's utterly dishonest. This gives you ~24952 miles around (Great Circle) which is correct to within a small margin of error.

40) From near Cape Horn, Chile to Port Philip in Melbourne, Australia the distance is 10,500 miles, or 143 degrees of longitude away. Factoring in the remaining degrees to 360 makes for a total distance of 26,430 miles around this particular latitude, which is over 1500 miles wider than Earth is supposed to be at the equator, and many more thousands of miles wider than it is supposed to be at such Southern latitudes.

Taxonomy: Latitude/Longitude Strawman

Duplicate of #39 - Same error, distance is wrong, does latitude/longitude math incorrectly.

41) Similar calculations made from the Cape of Good Hope, South Africa to Melbourne, Australia at an average latitude of 35.5 degrees South, have given an approximate figure of over 25,000 miles, which is again equal to or greater than the Earth’s supposed greatest circumference at the equator. Calculations from Sydney, Australia to Wellington, New Zealand at an average of 37.5 degrees South have given an approximate circumference of 25,500 miles, greater still! According to the ball-Earth theory, the circumference of the Earth at 37.5 degrees Southern latitude should be only 19,757 statute miles, almost six thousand miles less than such practical measurements.

Taxonomy: Latitude/Longitude Strawman

Duplicate of #39 - Same error, distance is wrong, does latitude/longitude math incorrectly.

42) In the ball-Earth model Antarctica is an ice continent which covers the bottom of the ball from 78 degrees South latitude to 90 and is therefore not more than 12,000 miles in circumference. Many early explorers including Captian Cook and James Clark Ross, however, in attempting Antarctic circumnavigation took 3 to 4 years and clocked 50-60,000 miles around. The British ship Challenger also made an indirect but complete circumnavigation of Antarctica traversing 69,000 miles. This is entirely inconsistent with the ball model.

Taxonomy: Factual Error

These journeys went many places and did not only circumnavigate Antarctica, for example, for Cook:

Show me detailed logs with star position and time observations and put them into Google Earth, following exactly those paths, and then we can talk. Until then this nonsense is clear and obvious deception.

43) If Earth was a ball there are several flights in the Southern hemisphere which would have their quickest, straightest path over the Antarctic continent such as Santiago, Chile to Sydney, Australia. Instead of taking the shortest, quickest route in a straight line over Antarctica, all such flights detour all manner of directions away from Antarctica instead claiming the temperatures too cold for airplane travel! Considering the fact that there are plenty of flights to/from/over Antarctica, and NASA claims to have technology keeping them in conditions far colder (and far hotter) than any experienced on Earth, such an excuse is clearly just an excuse, and these flights aren’t made because they are impossible.

Taxonomy: Flight Paths

Airlines fly where people can fill the planes -- they don't fly all possible routes just because 1 person sometimes wants to go that way. People sometimes have to fly to a major hub to get to a less frequent destination.

And this is debunked by QF27/28 anyway:

There is no way to make that flight time on the Flat Earth map -- it would be insanely far and to "fool" everyone it would have to be even long so they could fly the crazy arc flight to avoid the US and all points in between.

So this claim busted.

44) If Earth was a ball, and Antarctica was too cold to fly over, the only logical way to fly from Sydney to Santiago would be a straight shot over the Pacific staying in the Southern hemisphere the entire way. Re-fueling could be done in New Zealand or other Southern hemisphere destinations along the way if absolutely necessary. In actual fact, however, Santiago-Sydney flights go into the Northern hemisphere making stop-overs at LAX and other North American airports before continuing back down to the Southern hemisphere. Such ridiculously wayward detours make no sense on the globe but make perfect sense and form nearly straight lines when shown on a flat Earth map.

Taxonomy: Flight Paths

Duplicate of #43

45) On a ball-Earth, Johannesburg, South Africa to Perth, Australia should be a straight shot over the Indian Ocean with convenient re-fueling possibilities on Mauritus or Madagascar. In actual practice, however, most Johannesburg to Perth flights curiously stop over either in Dubai, Hong Kong or Malaysia all of which make no sense on the ball, but are completely understandable when mapped on a flat Earth.

Taxonomy: Flight Paths

Duplicate of #43

46) On a ball-Earth Cape Town, South Africa to Buenos Aries, Argentina should be a straight shot over the Atlantic following the same line of latitude across, but instead every flight goes to connecting locations in the Northern hemisphere first, stopping over anywhere from London to Turkey to Dubai. Once again these make absolutely no sense on the globe but are completely understandable options when mapped on a flat Earth.

Taxonomy: Flight Paths

Duplicate of #43

47) On a ball-Earth Johannesburg, South Africa to Sao Paolo, Brazil should be a quick straight shot along the 25th Southern latitude, but instead nearly every flight makes a re-fueling stop at the 50th degree North latitude in London first! The only reason such a ridiculous stop-over works in reality is because the Earth is flat.

Taxonomy: Flight Paths

Duplicate of #43

48) On a ball-Earth Santiago, Chile to Johannesburg, South Africa should be an easy flight all taking place below the Tropic of Capricorn in the Southern hemisphere, yet every listed flight makes a curious re-fueling stop in Senegal near the Tropic of Cancer in the North hemisphere first! When mapped on a flat Earth the reason why is clear to see, however, Senegal is actually directly in a straight-line path half-way between the two.

Taxonomy: Flight Paths

Duplicate of #43

49) If Earth were a spinning ball heated by a Sun 93 million miles away, it would be impossible to have simultaneously sweltering summers in Africa while just a few thousand miles away bone-chilling frozen Arctic/Antarctic winters experiencing little to no heat from the Sun whatsoever. If the heat from the Sun traveled 93,000,000 miles to the Sahara desert, it is absurd to assert that another 4,000 miles (0.00004%) further to Antarctica would completely negate such sweltering heat resulting in such drastic differences.

Taxonomy: Climate

It's a complete misrepresentation to say "another 4,000 miles" -- that distance itself is irrelevant. The issue is that on a Globe then angle of the light hitting the land has changes from coming nearly straight down between the Tropics to a nearly zero degree angle at the poles.

Please show me your equations that demonstrate what you claim, because we have this model for a Globe. You are also ignoring other factors that impact climate, ocean currents, altitude, etc. There are wildly different climates just dozens of miles apart -- even microclimates due to terrain and other factors.

Here is the Globe model:

50) If the Earth were truly a globe, the Arctic and Antarctic polar regions and areas of comparable latitude North and South of the equator should share similar conditions and characteristics such as comparable temperatures, seasonal changes, length of daylight, plant and animal life. In reality, however, the Arctic/Antarctic regions and areas of comparable latitude North/South of the equator differ greatly in many ways entirely inconsistent with the ball model and entirely consistent with the flat model.

Taxonomy: Climate

Duplicate of #49 - incident angle, northern ocean currents are warmer, antarctica is highly elevated over the arctic, etc.

51) Antarctica is by far the coldest place on Earth with an average annual temperature of approximately -57 degrees Fahrenheit, and a record low of -135.8! The average annual temperature at the North Pole, however, is a comparatively warm 4 degrees. Throughout the year, temperatures in the Antarctic vary less than half the amount at comparable Arctic latitudes. The Northern Arctic region enjoys moderately warm summers and manageable winters, whereas the Southern Antarctic region never even warms enough to melt the perpetual snow and ice. On a tilting, wobbling, ball-Earth spinning uniformly around the Sun, Arctic and Antarctic temperatures and seasons should not vary so greatly.

Taxonomy: Climate

Duplicate of #49 - incident angle, northern ocean currents are warmer, antarctica is highly elevated over the arctic, etc.

52) Iceland at 65 degrees North latitude is home to 870 species of native plants and abundant various animal life. Compare this with the Isle of Georgia at just 54 degrees South latitude where there are only 18 species of native plants and animal life is almost non-existent. The same latitude as Canada or England in the North where dense forests of various tall trees abound, the infamous Captain Cook wrote of Georgia that he was unable to find a single shrub large enough to make a toothpick! Cook wrote, “Not a tree was to be seen. The lands which lie to the south are doomed by nature to perpetual frigidness - never to feel the warmth of the sun’s rays; whose horrible and savage aspect I have not words to describe. Even marine life is sparse in certain tracts of vast extent, and the sea-bird is seldom observed flying over such lonely wastes. The contrasts between the limits of organic life in Arctic and Antarctic zones is very remarkable and significant.”

Taxonomy: Climate

Duplicate of #49 - incident angle, northern ocean currents are warmer, antarctica is highly elevated over the arctic, etc.

53) At places of comparable latitude North and South, the Sun behaves very differently than it would on a spinning ball Earth but precisely how it should on a flat Earth. For example, the longest summer days North of the equator are much longer than those South of the equator, and the shortest winter days North of the equator are much shorter than the shortest South of the equator. This is inexplicable on a uniformly spinning, wobbling ball Earth but fits exactly on the flat model with the Sun traveling circles over and around the Earth from Tropic to Tropic.

Taxonomy: Factual Error

For equal latitudes N and S they have equally long/short days for equal portions of the year.

54) At places of comparable latitude North and South, dawn and dusk happen very differently than they would on a spinning ball, but precisely how they should on a flat Earth. In the North dawn and dusk come slowly and last far longer than in the South where they come and go very quickly. Certain places in the North twilight can last for over an hour while at comparable Southern latitudes within a few minutes the sunlight completely disappears. This is inexplicable on a uniformly spinning, wobbling ball Earth but is exactly what is expected on a flat Earth with the Sun traveling faster, wider circles over the South and slower, narrower circles over the North.

Taxonomy: Factual Error

The Sun would have to race around the longer Tropic of Capricorn 58% faster than the shorter Tropic of Cancer... and yet nobody notices the sun moving that much faster?

See: Flat Earth Follies: Nearby Sun Impossible

55) If the Sun circles over and around the Earth every 24 hours, steadily travelling from Tropic to Tropic every 6 months, it follows that the Northern, central region would annually receive far more heat and sunlight than the Southern circumferential region. Since the Sun must sweep over the larger Southern region in the same 24 hours it has to pass over the smaller Northern region, its passage must necessarily be proportionally faster as well. This perfectly explains the differences in Arctic/Antarctic temperatures, seasons, length of daylight, plant and animal life; this is why the Antarctic morning dawn and evening twilight are very abrupt compared with the North; and this explains why many midsummer Arctic nights the Sun does not set at all!

Taxonomy: Factual Error

That's some nice CGI you got there, but what you do not have is any evidence of the Sun's motion changing or the ground track distance being much larger in the South or the morning dawn being any different from in the North at the same latitudes at opposite times of the year.

56) The “Midnight Sun” is an Arctic phenomenon occurring annually during the summer solstice where for several days straight an observer significantly far enough north can watch the Sun traveling circles over-head, rising and falling in the sky throughout the day, but never fully setting for upwards of 72+ hours! If the Earth were actually a spinning globe revolving around the Sun, the only place such a phenomenon as the Midnight Sun could be observed would be at the poles. Any other vantage point from 89 degrees latitude downwards could never, regardless of any tilt or inclination, see the Sun for 24 hours straight. To see the Sun for an entire revolution on a spinning globe at a point other than the poles, you would have to be looking through miles and miles of land and sea for part of the revolution!

Taxonomy: Globe Strawman

Um no, the claim is that the rotational axis of the Earth is tilted relative to the ecliptic by approximately 23.43696° (a value which varies over time and this fact is not accounted for by Flat Earth). When Earth's orbit has the North or South pole maximally tilted away from the Sun, a band of the Earth 23.4° wide remains in relative darkness for 24 hours.

This is trivial to demonstrate on a globe leaving me pondering why they would appear to be dishonest about this.

57) The establishment claims the Midnight Sun IS experienced in Antarctica but they conveniently do not have any uncut videos showing this, nor do they allow independent explorers to travel to Antarctica during the winter solstice to verify or refute these claims. Conversely, there are dozens of uncut videos publicly available showing the Arctic Midnight Sun and it has been verified beyond any shadow of a doubt.

Taxonomy: Globe Strawman

Actually there are numerous videos showing this and thousands of witnesses.

Antarctic midnight sun has been verified beyond any shadow of a doubt.
Notice how a lot of Flat Earth "evidence" is "so and so hasn't produced the evidence I demand?"

58) The Royal Belgian Geographical Society in their “Expedition Antarctique Belge,” recorded that during the most severe part of the Antarctic winter, from 71 degrees South latitude onwards, the sun sets on May 17th and is not seen above the horizon again until July 21st! This is completely at odds with the ball-Earth theory, but easily explained by the flat-Earth model. The Midnight Sun is seen from high altitudes in extreme Northern latitudes during Arctic summer because the Sun, at its inner-most cycle, is circling tightly enough around the polar center that it remains visible above the horizon for someone at such a vantage point. Likewise, in extreme Southern latitudes during Arctic summer, the Sun completely disappears from view for over 2 months because there at the Northern Tropic, at the inner-most arc of its boomerang journey, the Sun is circling the Northern center too tightly to be seen from the Southern circumference.

Taxonomy: Globe Strawman

Duplicate of #57

59) Quoting Gabrielle Henriet, “The theory of the rotation of the earth may once and for all be definitely disposed of as impracticable by pointing out the following inadvertence. It is said that the rotation takes twenty-four hours and that its speed is uniform, in which case, necessarily, days and nights should have an identical duration of twelve hours each all the year round. The sun should invariably rise in the morning and set in the evening at the same hours, with the result that it would be the equinox every day from the 1st of January to the 31st of December. One should stop and reflect on this before saying that the earth has a movement of rotation. How does the system of gravitation account for the seasonal variations in the lengths of days and nights if the earth rotates at a uniform speed in twenty-four hours!?”

Taxonomy: Globe Strawman

The Axial Tilt explains this perfectly and this is another Flat Earth self-debunk. The diagram he gives shows the situation only at the Equinox -- and on the Equinox we do indeed observer 12 hours of daylight and 12 hours of night equally all over the Globe. This is impossible on the Flat Earth without invoking magic.

Here is what the sunlight pattern would have to be for the various seasons on a Flat Earth.

Now that is a magical 'spotlight' Sun.

60) Anyone can prove the sea-horizon perfectly straight and the entire Earth perfectly flat using nothing more than a level, tripods and a wooden plank. At any altitude above sea-level, simply fix a 6-12 foot long, smooth, leveled board edgewise upon tripods and observe the skyline from eye-level behind it. The distant horizon will always align perfectly parallel with the upper edge of the board. Furthermore, if you move in a half-circle from one end of the board to the other whilst observing the skyline over the upper edge, you will be able to trace a clear, flat 10-20 miles depending on your altitude. This would be impossible if the Earth were a globe 25,000 miles in circumference; the horizon would align over the center of the board but then gradually, noticeably decline towards the extremities. Just ten miles on each side would necessitate an easily visible curvature of 66.6 feet from each end to the center.

Taxonomy: Horizon Geometry

The curvature here is again (see #1), an apparent horizon sagitta that curves around the observer. It is not, as Rowbotham here tries to suggest, the curvature of the Earth. This is how much of a fraud Rowbotham was and here we see Dubay parroting him. Is Dubay just an uninformed parrot or educated and studied person who should know better?

So yes, that curvature is very slight - this doesn't disprove a Globe. But we can, in fact, measure the horizon sagitta exactly as Rowbotham describes...

Image Credit: Clouds Givemethewillies

You can clearly see the horizon is not following the straight edge of the level. And since we have a straight edge in the frame we can eliminate lens distortion.

Here is a little trick I picked up -- you can compress just the width of an image to accentuate vertical changes -- I also increased the contrast a bit in this example -- do it yourself on the original.

If you want to do this yourself, get a high-resolution camera with a good quality, very wide-angle rectilinear lens and prove us wrong.

This one doesn't have a ruler but it's a beautiful example of how "looks flat" can be deceiving:

Image Credit: Nobody Hikes In Lunada Canyon

Again, just width compressed and contrast adjusted a bit:

Is that the actual curvature or some lens distortion -- the horizon is almost dead center and there is almost no other indications of fisheye distortion so it's unlikely to be much lens distortion. That's only about 4-6 pixels of apparent horizon sagitta.

61) If the Earth were actually a big ball 25,000 miles in circumference, the horizon would be noticeably curved even at sea-level, and everything on or approaching the horizon would appear to tilt backwards slightly from your perspective. Distant buildings along the horizon would all look like leaning towers of Piza falling away from the observer. A hot-air balloon taking off then drifting steadily away from you, on a ball-Earth would slowly and constantly appear to lean back more and more the farther away it flew, the bottom of the basket coming gradually into view as the top of the balloon disappears from sight. In reality, however, buildings, balloons, trees, people, anything and everything at right angles to the ground/horizon remains so regardless the distance or height of the observer.

Taxonomy: Horizon Geometry Strawman

Wrong, see #1 - and as for the tilt of distant buildings they tilt 1 degree every 69.1 miles -- you cannot see a 1 degree tilt on a hazy distant horizon. But what's worse for this nonsensical claim is that when you are looking at a building on the horizon and you can see the bottom of that building only then is the building actually at 90 degrees to the vertical to your line-of-sight to the base.

When you are standing next to a building and looking down at the base of it, the base of that building is tilted many many degrees to your line of sight. And as you look up the top of the building is tilted many degrees the other direction. We just normalize all this in our brain.

How far back is the face of this speaker tilted?

62) Samuel Rowbotham’s experiments at the Old Bedford Level proved conclusively the canal’s water to be completely flat over a 6 mile stretch. First he stood in the canal with his telescope held 8 inches above the surface of the water, then his friend in a boat with a 5 foot tall flag sailed the 6 miles away. If Earth were a ball 25,000 miles in circumference the 6 mile stretch of water should have comprised an arc exactly 6 feet high in the middle, so the entire boat and flag should have ultimately disappeared, when in fact the entire boat and flag remained visible at the same height for the entire journey.

Taxonomy: Failed to account for Refraction

Wallace debunked this.

63) In a second experiment Dr. Rowbotham affixed flags 5 feet high along the shoreline, one at every mile marker. Then using his telescope mounted at 5 feet just behind the first flag looked over the tops of all 6 flags which lined up in a perfectly straight line. If the Earth were a ball 25,000 miles in circumference the flags should have progressively dipped down after the first establishing line of sight, the second would have descended 8 inches, 32 inches for the third, 6 feet for the fourth, 10 feet 8 inches for the fifth, and 16 feet 8 inches for the sixth.

Taxonomy: Failed to account for Refraction

Duplicate of #62

64) Quoting “Earth Not a Globe!” by Samuel Rowbotham, “It is known that the horizon at sea, whatever distance it may extend to the right and left of the observer on land, always appears as a straight line. The following experiment has been tried in various parts of the country. At Brighton, on a rising ground near the race course, two poles were fixed in the earth six yards apart, and directly opposite the sea. Between these poles a line was tightly stretched parallel to the horizon. From the center of the line the view embraced not less than 20 miles on each side making a distance of 40 miles. A vessel was observed sailing directly westwards; the line cut the rigging a little above the bulwarks, which it did for several hours or until the vessel had sailed the whole distance of 40 miles. The ship coming into view from the east would have to ascend an inclined plane for 20 miles until it arrived at the center of the arc, whence it would have to descend for the same distance. The square of 20 miles multiplied by 8 inches gives 266 feet as the amount the vessel would be below the line at the beginning and at the end of the 40 miles.”

Taxonomy: Assertion

This is a nice claim, I would like to see the evidence because this isn't what we actually observe.

We can see the boat very clearly sinking below the horizon. If you want to appeal to 'refraction' or 'perspective' to excuse this then you can't make claim #64 without any actual evidence.

If this were perspective the boat would just appear smaller, we wouldn't be missing half the boat.

This is because perspective is just a consequence of the line-of-sight changing angles as an object recedes from an observer.

65) Also Quoting Dr. Rowbotham, “On the shore near Waterloo, a few miles to the north of Liverpool, a good telescope was fixed, at an elevation of 6 feet above the water. It was directed to a large steamer, just leaving the River Mersey, and sailing out to Dublin. Gradually the mast-head of the receding vessel came nearer to the horizon, until, at length, after more than four hours had elapsed, it disappeared. The ordinary rate of sailing of the Dublin steamers was fully eight miles an hour; so that the vessel would be, at least, thirty-two miles distant when the mast-head came to the horizon. The 6 feet of elevation of the telescope would require three miles to be deducted for convexity, which would leave twenty-nine miles, the square of which, multiplied by 8 inches, gives 560 feet; deducting 80 feet for the height of the main-mast, and we find that, according to the doctrine of rotundity, the mast-head of the outward bound steamer should have been 480 feet below the horizon. Many other experiments of this kind have been made upon sea-going steamers, and always with results entirely incompatible with the theory that the earth is a globe.”

Taxonomy: Assumptions, Refraction

Duplicates other claims - is a claim not evidence, ignores refraction, and makes assumptions about the rate of travel.

66) Dr. Rowbotham conducted several other experiments using telescopes, spirit levels, sextants and “theodolites,” special precision instruments used for measuring angles in horizontal or vertical planes. By positioning them at equal heights aimed at each other successively he proved over and over the Earth to be perfectly flat for miles without a single inch of curvature. His findings caused quite a stir in the scientific community and thanks to 30 years of his efforts, the shape of the Earth became a hot topic of debate around the turn of the nineteenth century.

Taxonomy: Unevidenced Claim

Duplicates of other claims but without even a whiff of new evidence.

67) The distance across the Irish Sea from the Isle of Man’s Douglas Harbor to Great Orm’s Head in North Wales is 60 miles. If the Earth was a globe then the surface of the water between them would form a 60 mile arc, the center towering 1944 feet higher than the coastlines at either end. It is well-known and easily verifiable, however, that on a clear day, from a modest altitude of 100 feet, the Great Orm’s Head is visible from Douglas Harbor. This would be completely impossible on a globe of 25,000 miles. Assuming the 100 foot altitude causes the horizon to appear approximately 13 miles off, the 47 miles remaining means the Welsh coastline should still fall an impossible 1472 feet below the line of sight!

Taxonomy: Ignores Refraction

I analyzed several cases where I could find actual evidence and every observation matches what is expected on a Globe with some reasonable amount of refraction. See Flat Earth Follies: Isle of Man, seen from the Great Orme

68) The Philadelphia skyline is clearly visible from Apple Pie Hill in the New Jersey Pine Barrens 40 miles away. If Earth were a ball 25,000 miles in circumference, factoring in the 205 foot elevation of Apple Pie Hill, the Philly skyline should remain well-hidden beyond 335 feet of curvature.

Taxonomy: Earth Curavture

Debunked and another factual error - it is about 32.44 miles away, not 40 miles. Also, while the ground is about 205 feet up there is a tower on the hill that can add another 50+ feet to the observer height.

See: Analysis: Apple Pie Hill to Philadelphia

69) The New York City skyline is clearly visible from Harriman State Park’s Bear Mountain 60 miles away. If Earth were a ball 25,000 miles in circumference, viewing from Bear Mountain’s 1,283 foot summit, the Pythagorean Theorem determining distance to the horizon being 1.23 times the square root of the height in feet, the NYC skyline should be invisible behind 170 feet of curved Earth.

Taxonomy: Earth Curvature

Duplicate of #68 - Bear Mountain is 39 miles away, not 60 miles. Another factual error.

Since Bear Mountain is 1,283' and it is 38.96 miles to the Empire State Building we expect to be able to see 100% of the Empire state building from this height -- since the horizon is ~43.9 miles away.

70) From Washington’s Rock in New Jersey, at just a 400 foot elevation, it is possible on a clear day to see the skylines of both New York and Philadelphia in opposite directions at the same time covering a total distance of 120 miles! If Earth were a ball 25,000 miles in circumference, both of these skylines should be hidden behind over 800 feet of Earth’s curvature.

Taxonomy: Earth Curvature

Duplicate of #68 - The overlook is over 500 feet. New York is under 28 miles away and Philadelphia is under 60 miles. More lies. With standard refraction (15%) only about 400 feet of the bottoms of buildings in Philadelphia would be obscured.

However, I couldn't find an image that was definitely from this location of the Philadelphia skyline -- I would believe it could exist but someone will have to bring their evidence to me and then we can evaluate it. Now remember, since the buildings are twice the distance we expect them to only be 1/2 the angular size. That alone will pretty much destroy any claim we're seeing the 'whole' building from here.

71) It is often possible to see the Chicago skyline from sea-level 60 miles away across Lake Michigan. In 2015 after photographer Joshua Nowicki photographed this phenomenon several news channels quickly claimed his picture to be a “superior mirage,” an atmospheric anomaly caused by temperature inversion. While these certainly do occur, the skyline in question was facing right-side up and clearly seen unlike a hazy illusory mirage, and on a ball-Earth 25,000 miles in circumference should be 2,400 feet below the horizon.

Taxonomy: Earth Curvature

Duplicate of #68, also ignores Refraction

See Chicago skyline 'looming' from MI - explained

And yes, it IS refraction -- see these side-by-sides from Joshua Nowicki's video - you can clearly see the position of the lake shifting wildly and the buildings stretching and flickering.

72) October 16, 1854 the Times newspaper reported the Queen’s visit to Great Grimsby from Hull recording they were able to see the 300 foot tall dock tower from 70 miles away. On a ball-Earth 25,000 miles in circumference, factoring their 10 foot elevation above the water and the tower’s 300 foot height, at 70 miles away the dock tower should have remained an entire 2,600 feet below the horizon.

Taxonomy: Earth Curvature

The distance from Hull to Grimsby Dock Tower is about 15.28 miles not 70 miles -- giving us an estimate obscured height of no more than 87 feet (and probably less due to refraction).

73) In 1872 Capt. Gibson and crewmates, sailing the ship “Thomas Wood” from China to London, reported seeing the entirety of St. Helena Island on a clear day from 75 miles away. Factoring in their height during measurement on a ball-Earth 25,000 miles in circumference, it was found the island should have been 3,650 feet below their line of sight.

Taxonomy: Earth Curvature

Another factual error -- notice how sometimes he gives and subtracts observer height and this time we're just told "island should have been 3,650 feet below their line of sight"? 3,650 feet would be for an observer whose eye is half-way submerged under the water. How tall was this ship? I cannot find records of this voyage or this ship but the Moshulu main mast was reported as 58 meters off the Deck. If we're 70 meters up we can see considerably further.

But this is an unrepeatable experiment, there is no evidence supporting this claim. Someone claiming what they saw is not evidence - just look at how many claims in this series that are easy to test have been shown to be false. Maybe they were only 20 miles away? 30 miles?

Unlike other examples, there is no landmark given that I can verify in this case.

Dubay's lack of evidence does not constitute a proof. Maybe get one of your NBA Flat Earthers to commission a ship with a high-quality, high-resolution camera and get the evidence needed to prove the Earth is flat once and for all.

74) From Genoa, Italy at a height of just 70 feet above sea-level, the island of Gorgona can often be seen 81 miles away. If Earth were a ball 25,000 miles in circumference, Gorgona should be hidden beyond 3,332 feet of curvature.

Taxonomy: Earth Curvature

You're only seeing the tops of distant elevated land and the observer altitude in the image is definitely higher than 70 feet. This '70 foot' claim is completely made up.

See source video - you can see many of these shots are from tops of mountains and high buildings and even see an airplane flying underneath the observer in one shot.

75) From Genoa, Italy at a height of just 70 feet above sea-level, the island of Corsica can often be seen 99 miles away. If Earth were a ball 25,000 miles in circumference, Corsica should fall 5,245 feet, almost an entire mile below the horizon.

Taxonomy: Earth Curvature

Duplicate of #74

76) From Genoa, Italy 70 feet above sea-level, the island of Capraia 102 miles away can often be seen as well. If Earth were a ball 25,000 miles in circumference, Capraia should always remain hidden behind 5,605 feet, over a mile of supposed curvature.

Taxonomy: Earth Curvature

Duplicate of #74

77) Also from Genoa, on bright clear days, the island of Elba can be seen an incredible 125 miles away! If Earth were a ball 25,000 miles in circumference, Elba should be forever invisible behind 8770 feet of curvature.

Taxonomy: Earth Curvature

Duplicate of #74 (more like "on days with more than normal refraction")

78) From Anchorage, Alaska at an elevation of 102 feet, on clear days Mount Foraker can be seen with the naked eye 120 miles away. If Earth were a ball 25,000 miles in circumference, Mount Foraker’s 17,400 summit should be leaning back away from the observer covered by 7,719 feet of curved Earth. In reality, however, the entire mountain can be quite easily seen standing straight from base to summit.

Taxonomy: Earth Curvature

The image looks to be from above 102 feet, we can see that we're well above the distant buildings.

We can line this up in Google Earth Pro and we find the following details match this photo very well:

Lat: 61.181109817°
Long: -149.862923906°
Elevation: 330.00m (Above Sea Level)
Heading: 339.20°
Tilt: 88.40°
Roll: 0.10°
H. FOV: 17.09°
V. FOV: 7.37°

I also found this image on Flickr, where it says this was taken with a Nikon D90, with a 70mm lens (105mm in 35mm equivalent) but the image has clearly been cropped since it's not in the original aspect ratio and down-resed (I would love to have the original). So this puts us about 1083 feet up.

But with this information we can estimate the number of pixels we expect the mountain to be -- first we will compensate for our 2 degree "lean" -- that's 17,400 * cos(2°) gives us 17,389 -- so our mountain would appear 11 feet shorter (hint: this will make zero difference). Now we can take the angular size of the mountain at 132.93 miles (701,870 feet) as 2*arctan(17389/2/701870) = 1.41944°.

So that is 1.41944°/7.37° = 19.26% of our image or 0.1926*439 pixels or ~84.5 pixels high.

Full equation: ([2*arctan([17400*cos(2°)]/2/701870) rad]/7.37°)*439 [Wolfram|Alpha] ~ 84.55

We can also estimate this from the other direction -- from 330 meters up we would expect 5724 feet to be hidden which is 5724/17400 or about 33% of the mountain hidden, 33% of 85 pixels is 28 pixels.

Now, how about that -- both an angular size estimation and the hidden amount just happen to agree with our observation. Flat Earthers will assert, completely without any supporting evidence or rationale, that this is the entirety of the mountain. But take the same image from much higher up and you'll see more and more of the mountain -- just look at the next claim for evidence of that, we can clearly see more of the mountain in this image even though we're further away (not on the shore) but Dubay will claim you see the entire mountain top-to-base.

And again with the leaning... It's less than 2° "lean" and ~130 miles away and the ground is sloped -- where did Dubay measure this exactly? He's appealing to some nonsensical idea that you would just see a mountain 'leaning' 2° with slopes that vary as a mountain would. How could you possibly detect this?

Finding observer using Google Earth Pro image overlay:

79) From Anchorage, Alaska at an elevation of 102 feet, on clear days Mount McKinley can be seen with the naked eye from 130 miles away. If Earth were a ball 25,000 miles in circumference, Mount McKinley’s 20,320 foot summit should be leaning back away from the observer and almost half covered by 9,220 feet of curved Earth. In reality, however, the entire mountain can be quite easily seen standing straight from base to summit.

Taxonomy: Earth Curvature

That's the whole mountain? No it isn't. Already disproved by #78

And while this claim does not meet any Burden of Proof (it's bald assertion) I can show good cause for why it is also a factual misrepresentation.

From the original on flickr it looks to me we're higher than 102 feet over the water (we're well over the cranes). This images is too low-resolution and blurry to get a lock on the location but we're about 133 miles from Denali here. The mountains are about 14.4 miles apart so we can use that to get an estimate on the angular height. 2*arctan(14.4/2/133) gives us 6.197° for 168 pixels, which means Denali's 20,310' height would be 2*arctan(20310/2/(133*5280)) or 1.657° which should be about 45 pixels high.

Which puts the base of the mountain well below the horizon here.

We also cannot see exactly where the horizon would be here because there is a large hill in the foreground but let's calculate where it would be and we can see if that looks reasonable.

For 102' observer 9707.6' should be hidden which is (9707.7/20310)*45 or 21.5 pixels up (orange).
For 220' observer 8796.9' should be hidden which is (8796.9/20310)*45 or 19.5 pixels up (green).

Which looks about right -- so this is consistent with the Globe and a significant portion of the mountain is hidden by the curvature of the Earth. If you don't like this approach, too bad -- get better evidence.

And again with the lean is a ridiculous claim, from #78.

80) In Chambers’ Journal, February 1895, a sailor near Mauritius in the Indian Ocean reported having seen a vessel which turned out to be an incredible 200 miles away! The incident caused much heated debate in nautical circles at the time, gaining further confirmation in Aden, Yemen where another witness reported seeing a missing Bombay steamer from 200 miles away. He correctly stated the precise appearance, location and direction of the steamer all later corroborated and confirmed correct by those onboard. Such sightings are absolutely inexplicable if the Earth were actually a ball 25,000 miles around, as ships 200 miles distant would have to fall approximately 5 miles below line of sight!

Taxonomy: Tall Tale

These guys Love the late 1800's where nothing can be verified.

Funny how, even with massive telescopes we have today, we cannot see other ships 200 miles from near sea-level. Ships cannot even see fairly tall lighthouses from 200 miles away.

Must have been some magical eyes since a 200' ship at 200 miles would be well below human angular resolution vision to see by half.

How about this -- a repeatable and verifiable observation of a 100' lighthouse from 200 miles out?

Got one?

81) The distance from which various lighthouse lights around the world are visible at sea far exceeds what could be found on a ball-Earth 25,000 miles in circumference. For example, the Dunkerque Light in southern France at an altitude of 194 feet is visible from a boat (10 feet above sea-level) 28 miles away. Spherical trigonometry dictates that if the Earth was a globe with the given curvature of 8 inches per mile squared, this light should be hidden 190 feet below the horizon.

Taxonomy: Refraction, Haze

You can see a light that is illuminating haze/fog/particulates from further away than you can see the actual light.

Also doesn't account for refraction.

Provides no verifiable evidence for the claim.

82) The Port Nicholson Light in New Zealand is 420 feet above sea-level and visible from 35 miles away where it should be 220 feet below the horizon.