Plus in genesis it mentions light and dark on the earth being separate, which also implies a sphere. And that's how it looks when earth is viewed from outer space.
My personal opinion is that all gods are real but not what we commonly think they are. I hate to use the term "aliens" because that makes me sound like a nut, but basically I believe aliens have influenced our creation and development, and have manifested themselves as "gods" to give us something tangible to understand.
To me this explains the circle vs sphere thing. The bible talks about people being taken straight to the heavens (more than just Jesus, it happens at least two other times. One to Elijah, and another to somebody else that I can't remember their name). So perhaps the writers viewed the earth from space in some manner, and had no knowledge of what spheres and the like and simply described it as a circle because that's what it appeared to be to them.