Khoog/globe of the earth (Isa. 40:22)

Isaiah 40:22 refers to the God who "sits upon the circle of the earth." The Hebrew word for 'circle' is khoog. It literally means a sphere or globe. Isaiah wrote his book in approximately 725 B.C. and his contemporaries all "knew" that the earth was flat (and likely resting atop giant elephants). The idea of a flat earth persisted until Columbus sailed to the Americas and Magellan circumnavigated the globe in 1520. It was always round. It did not become round when mankind made this discovery. So how did Isaiah, not being a sailor or astronomer, know this over 2,000 years before men "discovered" this truth? God told him.