Our Planets Rotate Around the Sun – And None of Them Are Flat!

Used to chart movements in the heavens of other astronomical problems, the nine-ringed armillary sphere has been in use since at least AD 140 Greece. The center sphere originally represented the earth, in keeping with┬áPtolemy’s idea of the planets orbiting the earth. It later came to represent the sun with the Copernican theory of planets, […]