The Earth is mostly spherical.

I'm very glad the opponent has accepted! As he mentioned, this will be a continuation of the previous debate. (http://www.debate.org...)I will briefly sum up arguments made for and against a flat Earth, then address them in more detail. This summation covers all arguments for a flat Earth and all arguments I will be continuing from the previous debate. My new arguments will not be outlined here, as they have yet to be made.Previous Flat Earth Arguments1. Distances sighted defy notion of spherical earth.2. Reflections on water defy ocean curvature.3. Flight paths indicate a flat earth.4. Gyroscopes remain steady during Earth traversal, implicating flat earth. Previous Spherical Earth Arguments [The following are the arguments I am keeping from the previous debate.]1. No "edge of earth" ever documented. 2. International conspiracy highly unlikely. Upcoming Spherical Earth Arguments 1. Satellites must exist and must orbit a spherical earth.2. Aerospace students learn spherical earth mathematics. 3. Ockam's Razor hedges toward spherical earth4. Timezones and the nature of the sun. This should be sufficient for this round. I may introduce new arguments in the next round and my opponent certainly has that right as well. I honestly enjoy considering flat earth arguments and I hope more are presented. Rebuttal of Opponent's Case1. Distances sighted defy spherical earth. I believe I did cover this point quite well in the previous debate. It would be difficult to call the skyline a mirage if it consistently appeared. However, there are many times in which the weather is nominal and the image fails to show up. More importantly, there are many occasions in which the image does take the more common form of a mirage -- in that it appears inverted in both the horizontal and vertical directions, as the image in the link provided shows. [1]If the Earth were flat, one would expect to be able to always see the skyline from 60 miles, weather permitting. As my evidence demonstrates, this is clearly not the case. As such, this particular skyline mirage indicates that Earth must have a curvature, since the city is not always visible (even in good weather.)2. Reflections of sun on water.The opponent is basically saying that the sun's rays on water should look different if the ocean actually had a curvature. This claim, however, is not substantiated. Looking at the photo provided, we see the sun setting over the horizon, producing a linear, gradiated line of reflection which extends toward the camera. This is the expected behavior of light in both a flat and spherical earth model. The following image illustrates this: Note that since the sun is well above the Earth, the reflection occurs despite the curvature, or lack thereof, of the Earth. Also notice that this reflection happens even under the dramatically increased curvature in my "spherical earth" example. For a more practical example, remember that you can clearly see a distorted image of yourself in a funhouse mirror. Despite the curve in the surface, a reflection still occurs. The sun's image would also be slightly distorted, but the intensity of the light along with the relatively small curvature of the Earth at normal viewing distances makes that distortion unobvious. 3. Flight paths.To start, the direct path between two destinations is often impractical. The first deals with fuel. Large passenger aircraft have a limited supply of fuel and can only go so far before needing to refuel. This is why flights over particularly long stretches of ocean are uncommon. The second, and more critical explanation, deals with economic efficiency. Flights are meant to appeal to as many people as possible, so as to always keep the plane full of people. The number of people wishing to go from Sydney, Australia to South America is likely never enough to fill a plane. As such, making a stop at LAX before heading south would be economically feasible. Rich nations tend to use airfare significantly more often than poorer nations. This means that the demand for convenient flights is often high in North America, China and Western Europe, whereas people from Africa, South America and Easter Europe will not fly as often. As such, airlines want to pick up passengers as much as possible in these countries with heavy airline usage. 4. GyroscopesGyroscopes are fascinating pieces of technology. I'll here explain how a gyroscope works and what this says about the opponent's arguments.A gyroscope is basically a wheel affixed to rotational structures that allow the gyroscope to all places in a 3D space. A gyroscope is useful in that it tends to maintain its particular orientation in space. Why?Conservation of Angular Momentum, of course. Whenever something is rotating, it has a tendency to maintain its position so long as the rotation persists. This is why a top remains upright while spinning, even though it does not (easily) stand upright when it is at rest. Similarly, gyroscopes spin at high RPM's so as to maintain position. [2] This high rotation speed, along with the Conservation of Momentum, explains why gyroscopes do not "wobble about". There are a variety of different types of gyroscopes, but here we'll look at "space gyros" and "Earth gyros". According to the referenced source, a space gyro "moves in all three planes and is stabilized to a point in space". An Earth gyro "moves in all three planes, but is held in one plane by Earth's gravity." Airplanes use Earth gyros.While I won't be making gravity-specific arguments myself, gravity is the rebuttal to this point. This "downforce" that we feel on Earth stabilizes an Earth gyro in one plane. Regardless of what causes this downforce, the force itself insures that the gyro's direction is parallel to the direction of the downforce. On a flat Earth, one would expect to see an Earth gyro remain unchanged if you fly in a straight line. Similarly, the same effect would be seen if the Earth were spherical, since planes remain flying perpendicular to the direction of the downforce, essentially moving the plane about the center of the Earth just as the gyro is doing. Space gyros point to some fixed point "infinitely" distant, while earth gyros point directly away from the center of the planet.My ArgumentsFor the sake of space, I'll cover my "previous debate arguments" in the following round. Or maybe not at all. I'm unsure. Here, I'll present my fresh, new arguments. 1. Satellites exist and require a spherical Earth to function properly. Let it be assumed that at least a few satellites exists. I refer to the ISS, which can be seen from the Earth with a telephoto lens, and cell phone satellites, which are required for cellular service to work.In the spherical model, a satellite remains in orbit without needing to consume energy. In order for the flat earth model to be correct, there would need to be a way for satellites to orbit without consuming energy. (We know satellites do not consume great deals of energy for altitude purposes, since these satellites have remained in orbit so long.)This means that it cannot be said they orbit in a "circle" along the face of the planet, since that would require a constant acceleration to maintain direction. (In other words, they'd need to constantly turn.) So this is not possible. An orbit around the "edge" of the flat plate would create make seeing a satellite from a centrally located position impossible. (Yet we can see the ISS from many different places on Earth when it comes around.) An orbit "above and around" the flat earth would be equally as impossible, given that the perihelion (the point in which the orbit is closest to the Earth) would need to be very large, putting the satellite too far away for efficient communication whenever it comes above the centers of the flat part. 2. The way aerospace and orbital mechanics is taught. Let us assume that the Earth is flat. We know that the people who make our satellites, rockets and planes are college-educated engineers. We furthermore know that these students are taught according to the spherical earth model. Ie, the practical educational requirement for building an aircraft assumes round earthIf the Earth were actually flat, none of these things would work. Rockets would be sent up, turn toward a prograde velocity vector, then smack into the side of the flat earth. Firing retrograde to lower the orbit would also cause a sat to hit the earth. Even the fuel put into launchers assumes that one can take advantage of a spherical earth. These rockets wouldn't have enough juice to get anywhere if aerospace engineers were wrong. 3. Timezones indicate a spherical Earth. It is currently night here. If I call my friend in Paris, it will be light there. The opponent might claim that the sun is very near Earth. Ignoring known facts about the heat of the sun and what this would do to life on earth, this still doesn't explain local lighting. Fire (the sun is a big blob of what is essentially fire) produces light in all directions. As such, a ball (or flat disc) of fire would radiate light to all parts of the planet, as opposed to a spot light, which emits light directionally due to radial occlusion surfaces. It cannot be said this is "crepuscular ray action", since crepuscular rays are caused by clouds and it still turns night, even without a cloud in the sky. It cannot be said that there is some disc with holes in it blocking the sunlight in some areas, since we can clearly see distant stars in the night sky. ConclusionI've run out of space. I'll cover Ockam's next round, but it was not important enough to include here. I've adequately shown the opp's arguments to be false or a misunderstanding and presented evidence for a round earth. I look forward to round 3. 1 - http://www.freep.com...;2 - http://www.experimentalaircraft.info...;