Gravity doesn't exist. I don't need to prove that because it hasn't even been proven that gravity does exist.

Shape? We don't have that data. We are currently 2 dimensional in regards to Earth. We know a map. We can't comprehend a globe.

Size? Again, we are 2 dimensional. We only have the data that made it through the geographer. Past Antarctica could be anything from a barren icy wasteland to a tropical paradise.

Math only works under the assumption of a globe. So does science. If the earth is not a globe, it upends everything.

Space is mostly fake. The best consumer digital 📷 (*icon to denote not on a phone) cannot discern features even on Mars. It shows a strange, pulsating orb, no matter the atmospheric conditions.

And for that matter, the atmosphere is too tenuous to produce twinkling. The firmament keeps the air on earth. If there is any twinkling, it would be caused by the "waters above."