It's still a secret to many modern day observers who believe the earth is flat.
PTB the earth was flat during the temptation of Jesus, a really high mountain would, on a clear day you the Chinese empire beyond the himalayas. The Incas and Mayas too. Even in 1054 years from now, the Earth will have 4 corners again, , ( or be a 3 cornered pyramid perhaps to have volume)?
God could have opted for general relativity, the ancient mind most likely would have struggled to understand it.
He did, e = mc^2, in Isaiah 40:26. stars made from energy. one of the handful of scriptures that come close to reality.