Spherical Earth vs. Flat Earth

C.1 Gravity Intro to Gravity Gravity is defined by the formula Fg=G*(M1*M2)/R2. Where G is the gravitational constant, M1 and M2 are the masses of the two objects that are being gravitationally attracted, and R is the distance between the two objects.(1) This formula describes the force that attracts any two objects, not at the quantum level. The gravitational force can be used to explain the reason behind why planets orbit stars, and material can be held on to large planetary objects. Evidence for Gravity Although this part may not seem relevant to this debate, the gravitational force demands a spherical Earth. Therefore, the burden of proof is on me to provide the most convincing evidence for gravity, and it is up to my opponent to describe some alternate phenomenon to replace gravity, that fits the idea of a flat Earth.I. Why objects fall down My opponent must have a reason, besides the concept of gravity, as to why objects fall down in the first place. There must be some kind of force that attracts objects to Earth, and according the Universal Law of Gravitational Attraction, the equation for gravity accurately describes this effect. The gravitational formula explains as to why larger, more massive, celestial bodies would exert a much greater gravitational force than smaller, less massive objects. If M1 increases, and is larger than M2, while M2 and “R” remain constant, then the gravitational attraction will proportionally increase to M1. (1) This effect describes as to why humans, and other objects on Earth will fall down to Earth itself. Because, even though those smaller objects are exerting a gravitational force, the gravitational effect from Earth is much greater, and thus the objects will “fall” to Earth and not vice versa. “Flat Earthers” may try refuting this argument by claiming the Earth is a disc that constantly accelerates upwards at a rate of 9.8 m/s/s. Although this will solve the problem as to why things fall down on Earth, it will not address the next few points.II. Orbiting Moons, and other celestial bodies Originally viewed by, Galileo Galilei, one can see the Moons of Jupiter revolving around the planet Jupiter. Galileo was able to see the moons around Jupiter by making significant improvements to the telescope, by increasing the magnification 20x. Because the multiple moons clearly revolve around Jupiter, this raises questions as to *why* the moons are going around, specifically Jupiter, in the first place. (2) This is where the concept of gravity comes in. Gravity, as a force, accurately explains and describes how Moons and other celestial bodies orbit other, more massive celestial bodies. Even though the Moons are “falling” into Jupiter, they still have some velocity. This makes them “fall” and “miss” Jupiter at the same time, resulting in an orbit. This is known as the centripetal force. (3) My explanation of orbits was extremely simplified, and if my opponent likes, I can give a more in depth, mathematical representation of orbits, and how they relate to gravity, in the next round. Although, here is a graph that visually demonstrates my point. III. Sattilites Man-made satellites such as the ISS can be seen with the naked eye. However, using a telescope, a more detailed image of the ISS can be seen. Disregarding the ISS live stream, it would be impossible for the ISS to orbit a flat Earth. My claim is that the same force that keeps moons in an elliptical orbit can also be applied to the ISS. This would mean that the Earth would have to be spherical for that to occur. This image was taken from an amatuer telescope of the ISS: The image was taken Munich through the 80cm telescope of the Public Observatory in Munich. There are a multitude of more images of the ISS being taken from a telescope on the ground. Now, the very existence of the ISS is up for debate. However, my opponent must refute, with evidence that the image seen of the ISS is actually something else. Characteristics of a Sphere One of the main points that disprove the Flat Earth model are the characteristics of a sphere. The sphere, as a geometrical object, has the least surface area for any given volume. This gives the sphere the lowest Surface area to Volume ratio. (SA:V) Here is a graph that shows this phenomenon: If you take gravity into consideration, the gravitational pull occurs in ALL directions towards the center. This would mean that any piece of large rock would pull other pieces of large rocks towards it, in all directions, resulting in a three dimensional circle. (4) Furthermore, using that phenomenon, Earth’s own gravitational forces would morph the flat disc into a sphere. *My opponent may try refuting this argument by claiming that this model only works if gravity exists in the first place, however this is not the case*. If the Earth is somehow an accelerating disc, then according to Einstein's principle of Equivalence, (5) the same effect should occur. This is simply because the force due to acceleration (say, a disc going upwards) and gravity (say, a ball falling on a spherical earth) is almost impossible to differentiate. C.2 Angular Size of the Sun Another main point that disproves flat Earth is viewing the angular size of the sun. According to the Flat Earth Society, I am going to assume my opponent does not believe the sun is the alleged 93 million miles. Instead, I am assuming that we are debating that the sun is actually some 3,000 miles away and 32 miles wide. If the sun were somehow circling a flat Earth, then the observable size of the sun should change drastically, *during the period of a day*. This is simply because objects seem to get smaller, the farther they get away. Using a computer animation, this is what the sun should look like on a flat Earth. https://www.geogebra.org... Furthermore, as the animation shows, the sun should never really appear to set. This makes sense because if we were on a flat plane, we should see the sun at all times. This is because the sun’s rays would be traveling in a straight line, and the sun should be above the horizon, no matter where your location is on Earth. I will make additional arguments concerning shadows (and more) in my next round. Citations: http://www.physicsclassroom.com... https://en.wikipedia.org... http://hyperphysics.phy-astr.gsu.edu... https://en.wikipedia.org... http://www.einstein-online.info...