Tom keeps mentioning Einstein's equivalence principle. He says that it states that an accelerating body creates a gravitational field and this is what holds everything to the earth. I'm no physicist, but this seems to be a misinterpretation. What I've read about the equivalence principle is that being at rest in a gravitational field is the same as experiencing acceleration in free space.
For example, if you're blindfolded, you cannot tell the difference between standing on earth and standing in a rocket ship accelerating at 9.8 m/s2. The difference is that I couldn't stand outside the rocket ship and expect to be attracted to it. In other words, if you were to try to stand on the underside of the flat earth, you would fall off.
I know Tom disagrees with me, but I was wondering if someone a little more knowledgeable wanted to weigh in.