I've read through the FAQ, and the incredibly long thread attempting to explain gravity on a discworld, but have quite a few issues with the answers presented:
1. Applicaton of special relativity to an ever accelerating Earth:
In the example given, I saw a poor applcation of frame of reference in the example given. According to the theory of Special Relativity, it is true their is no "main frame of reference", but all frame of references are equally correct and must be causally related to each other.
To put into perspective why your example violates causality, you must first understand the basic tenements:
- The speed of light in a vacuum is a universal constant: it is a ratio derived from several other measured constants such as the permeability of free space. Frame of reference is not applicable because it is a constant, if I'm travelling at the speed of c, the speed of light in a vacuum will still be c. The whole point of the universal constants is they are just that, constants, and are exactly the same for ALL frames of reference, regardless of their relative velocity. To put it into a perspective that would fit your flawed frame of reference model, a photon would act as a universal frame of reference. Even if it becomes impossible to measure time and distance unambigously from the other frame of references, it does not matter, whatever these values are relative to the photon are the master reference.
This is why when measuring the causal relationship of two points the light cone experiment is used. It is the only way to determine whether or not two different objects wth different frames of reference have causal relationship.
Additionally, I have never seen a more irrelevant application of Lorentz transformation in my life. Your secondary school level of algebraic reasoning is hardly impressive. When dealing with objects in Minkowski spacetime, we must use Poincare transformations. These transformations imply that as an object continues to accelerate towards the speed of light, it will require an exponentially greater amount of energy until it requires more than an infinite amount of energy. It doesn't matter that to the frame of reference of someone inert it appears as though the object will never reach light speed, because it in fact will.
As the observer is inert, he doesn't have a moving causal horizon, this means that eventhough the Earth would appear to slow down infinetly as it approaches light speed, it in fact is not relative to the constant c. This is simply an illusion caused by the Earth slipping out of the inert observers causal horizon, therefore the causal relationship between the inert observer and the Earth based observer is broken, and the inert observers' observations become irrelevant and wrong. However, the Earth based observers causal link to the constant c is not broken, and neither is the inert observers. Therefore, in regards to the Earth based observer, the planet is still accelerating towards the speed of light at a constant rate of acceleration this means that either of two things must happen:
1. The Earth would continue to accelerate until the energy needed to contnue accelerating is more than infinity. It is unknown what would happen at this point, but it is generally considered an impossible situation anyways. Most likely the Earth would simply cease to accelerate and everybody would float off into space.
2. The Earth somehow breaks the speed barrier and voids causality; this would cause a causal loop where it becomes impossible to determine sequence of events from any frame of reference. To the inert observer, it would begin to appear as though the Earth is travelling back in time. This is considered mathematically unsound and therefore impossible.
2. Atmosphere:
You explained that oceans did not simply spill off the disc because of a 150ft wall sorrounding it. However you failed to explain how the atmosphere, another fluid, would be contained above the 150ft wall. I happen to live 2800m (more than 8000ft) above sea level, and am happy to report I have not yet asphixiated. Maybe you should have read the book Ringworld before makng this up.
3.Tides:
Your explanation of tides is extremely poor and shows little undertsanding of how tides work even from general wisdom viewpoint. Your wobble theory doesn't explain opposing tides that are caused by the moon's gravity's dfferential field on the ocean. The closest explanation you could give on the forums was an illogical moon/anti-moon theory that was sarcastically(and very poorly) explained by IvantheSomewha where he claimed two hemispheres acted in tandem to create the tide and opposing tide; yet he failed to explain how two moons have never been observed at the very same time. Near the equator, "boat moons" can often be observed as early as 1 PM, which would clearly conflict with a moon observed at night time at 1 AM on the opposing side.
And a combined wobble/moon theory still does not work because it would become impossible to explain when the moon happens to be on the same side as the wobble tilt, causing a double tide and no opposing tide.