From my understanding, Einstein's gravity describes the Earth's surface as accelerating upward while an object falls.
This is as much that I know about this.
But what is gravity ?
But you reject this out of hand as you claim that the earth is stationary. If it is stationary, then it cannot be accelerating.
I looked it up and actually... Universal Acceleration/Constant Upward Thrust:The Earth (the flat disk) is perpetually accelerating upwards at the same rate we experience gravity (9.8 m/s²), pushing everything down onto its surface... is a flat earth explanation for gravity.
But I also see that that's just one of several explanations.
The problem is - this deosn't work.
1) A stationary earth cannot be accelerating. So, like many Flat Earth explainations, it contradicts other FE claims.
2) If the earth is moving, this would remove one of the main reasons for thinking that the earth was flat (it looks and feels flat and stationary).
3) Perpetual accleration, starting from stationary 6000 years ago (Young Earth age) would mean that the earth is now travelling at approximately 1.9×10E15 m/s (or 4.1×10E15 mph) which is many orders of magnitude faster than the speed of light.
Einstein's Theory of Special Relativity would limit the speed to slightly less than the spped of light. But I fail to see how any Flat Earther could accept Einstein's theory while rejecting the far simpler theories of Newton.
4) Acceleration requires a force. But FE offer no explaination for this force. What causes the acceleration?
Getting back to 'what is gravity'?
Gravity can be the name we give to 'whatever it is' that results in things falling to the ground.
Then in physics people have come up with explainations for gravity (in science, explainations are called theories. A theory is not merely an idea, but the best explaination so far, and is supported by real world observations and testing / experiements).
Newton explained gravity as an attractive force between two objects with mass. This is an extremely weak force.
Einstein came up with an explaination that almost no one actually understands (requires advanced maths and concepts).
Newton's theory is accurate enough for most everyday calcualtions.