I retain my bias. The planet is neither the shape you prefer it to be, nor will it be precisely a sphere. Think of it as an egg in a womb; the pre-born will try to enter it from all angles. Replace the egg with the beginnings of this world, and the pre-born with varying rocks and space debris, pulled by the cosmic forces. ...That[i] isn't [/i]all I have to say. [spoiler]With numerous factors, the planet's natural shape is a sphere, albeit slightly malformed due to other factors that correlate and are irremovable. To state that the planet is 2-dimensional (hence, flat) or equivalent is to deny the obvious values mentioned here: -Vehicles such as aircraft and boats can travel in the direction of your preferred worldshape's edge and 'appear' on the opposing edge, like in a game of Risk or Pacman. -Due to our scale being so insignificant, we mistake the world as flat. This is but a perspective. Terrain shape also comes into play here. There is no haze, fog, or atmospheric distortion causing this inability to see that other side, merely the shape of the planet; if the atmosphere was 'pulled inward' to block the other side, then wouldn't any boat passing it be thus deprived of organic life due to sudden changes? -The Universal Accelerator cannot function because of how the universe is shaped. The Accelerator has no physical form, no energy source, nor is it some impossibly vast cosmic computer fan that blows us, impossibly so, upward. -Flat-Solar-System planets would be constantly in view and would likely blot out the sun in your cosmic definition. We would've died as a species many times over, if this was so. -If Gravity doesn't exist, then we would have no atmosphere for the atmosphere is comprised of gasses of various elements, pulled by the world's sheer size into it. This also means that objects would try to come at it from all angles, resulting in the not-quite-a-sphere we live on now.[/spoiler]