Flat Earth vs Globe Earth

As per the rules, I'll here talk about the opponent's arguments. Argument 1: Physics of Water The opponent starts with a faulty assumption about water. They state, “the natural physics of water is to find and maintain its level”. This is not entirely true. A liquid under the effects of gravity attempts to find its lowest energy state. It does this by attempting to make the surface of the liquid have an equal amount of potential energy from gravity everywhere along its surface. On a flat earth, this *would* translate to a level surface. On a spherical earth, this translates to a spherical surface, since every point on the surface is an equal distance from the center of gravity. (This distance is the radius of the sphere formed. A sphere is such that the radius is the same everywhere.) The word “bulge” is not the correct term to use, as “bulge” implies a change in curvature. In both models of the earth there is not a bulge. In both cases the curvature of water is unchanging. On a flat earth, there is no curvature. On a spherical earth, there is minimal curvature. In neither model does water attempt to move in physically impossible ways. Suppose V liters of water is held in some natural crater, surrounded by hills. If one takes an imaginary sphere starting at the center of the earth and expands it, the volume of the sphere that contains this physical structure will eventually equal V liters, and this is the shape the water will take. There is no “climbing uphill” or whatever. No physical model prescribes that behavior. We should additionally not be surprised to see the provided “evidence” showing a flat water surface. The curvature of the earth is quite minimal. On a sphere with circumference of ~25,000 miles, one expect waters to change slope by one degree every 70 miles. Such a minute change is not visibly observable under any non-extraterrestrial condition. When you are very close to a sphere, it looks very flat. The behavior observed in the images and video provided are exactly what one would expect on a flat earth and on a spherical earth. Thus, this cannot be considered evidence for the former. Argument 2: Flight Patterns This is one of the least valuable arguments in the Flat Earth repertoire because it completely ignores basic economics and reasonable safety concerns. An airline only makes a flight available if it is economical for an airline to do so. If there is not sufficient demand for direct flights from Sao Paulo to Johannesburg, then the airline will connect a major business hub in between, like London. In most all cases of suboptimal flight paths we see that the path takes the flight through a major hub. To pick up passengers. Who pay money. It is the same reason many people don’t have a road straight from their house to the Walmart. It is definitely more direct, but it isn’t economically sound. Next, airplanes rarely fly over antarctica for fairly obvious reasons. There are no nearby airports for planes to divert to in the case of an emergency. Twin-engine planes are not allowed to fly over the Antarctic. If there is an emergency and the plane crashes, everyone who survives the crash will eventually die. The polar cap is not a survivable environment. Due to magnetic oddities near the poles, navigation is very difficult. [1] All of these are entirely reasonable justifications for not regularly flying over the Antarctic. Sometimes flights do go this way. There are sightseeing flights. [2] Argument 3: No evidence of curvature The opponent believes that the fact that it is difficult to detect curvature while close to the earth is evidence that curvature does not exist. In the round earth model, being 100,000 ft in the air gives you a visual distance to horizon of 12.3 miles. [3] Again, a change in slope of 1 degree is expected every 70 miles. So you should not be able to see curvature from an airplane in the round earth model. As for images taken from space, it is again very difficult to see curvature unless you’re looking in the right direction. Because again, earth is very large. There are single images of partial curvature being observed, however. From the mentioned Apollo 17 [4]. From certain angles from the space station. [5] (We note that a fisheye can’t be being used here, as that would distort the equipment as well.) We further note that composite images don’t exactly qualify as “faking” an image, since NASA clearly notes when an image is a composite. There are a litany of full images taken from deep space craft. [6] From 1 million+ miles away, the curvature is quite apparent. Argument 4: Chicago Skyline The opponent literally gives the appropriate answer to her argument, then follows it with an anecdotal claim in hopes that this is a sufficient answer. The problem is that you can see much of the Chicago skyline from a distance where you should be able to see much less of it. Scientists explain this as a result of atmospheric lensing. This write up goes over the math and the phenomenon in excruciating detail. [7] In short, the Chicago skyline view is precisely what one would expect on a spherical earth. The mirage isn’t always there and it regularly changes shape, all dependent upon atmospheric factors -- tell-tale signs that a lensing phenomenon is taking place. We note that if the earth were flat, we’d expect to be able to see all of the Chicago skyline all the time. (Or none of it, during a fog.) And yet we only ever see the upper parts of the skyline, which is inconsistent with the flat earth model. Argument 5: Midnight Sun The opponent presents an phenomenon and asserts, without evidence, that we shouldn’t be able to see this. Since it takes more space to explain science than misunderstand it, I’ll relegate the answer to this largely to an article. [8] Midnight sun occurs when the earth’s axis is tilted toward the sun, so that people near polar areas don’t see the sun set for 24-48 hours at a time. (At the poles, sunshine can last as long at 6 months.) In short, observed occurrences of the midnight sun are consistent with what a spherical earth predicts. Moreso, there is a related phenomenon which occurs less close to the poles in which the sun dips below the horizon, but not enough for darkness to truly occur. Argument 6: Stars The opponent claims that Crux, the Southern Cross, should be visible from everywhere in the southern hemisphere, then asserts it is not. However, Crux *is* visible in the Southern Hemisphere. [9] It is not visible at all times of day, but a few hours every night Crux is certainly visible. The opponent then claims that this proves there is no southern hemisphere, but instead the “southern hemisphere” is actually the outer edge of the disc. We should note that, if this were true, the southern hemisphere should be able to see Polaris. In fact, the same stars should be visible everywhere on earth at the same time since we’d all be “facing” in the same direction. This is clearly not the case, so we can only see this as evidence of a spherical earth. The opponent’s point about Sigma Octanis seems to be that the star is difficult to see, so it might not exist, and also the stars appear to move differently across the sky based upon where you are at. I’m not getting the relevance of this point. Sigma Octanis is not a bright star, this is true. [10] Stars do look different depending upon where you are, which is evidence for a spherical earth. On a flat earth, the night sky would look the same to everyone at all times. We would all be looking at the same hemisphere of the night sky. But this is clearly not the case. Summary The opponent’s arguments are based upon misunderstandings of basic science or the mentioning of facts that would be the case on both the round and flat earth. We find no compelling evidence for the flatness of the earth. Sources: 1 - goo.gl/BFbNXo2 - goo.gl/fApgYn3 - oo.gl/RkT1QQ4 - goo.gl/efRPCC5 - goo.gl/TrNvMN6 - goo.gl/6h4RyB7 - goo.gl/iKRn1c8 - goo.gl/u4FjuY9 - goo.gl/zFszzK10 - goo.gl/J5To4H