When you first learned about the Solar System, you probably saw diagrams that made it look orderly, with planets arranged in ...
"Either nobody leaves their planet, or we are in fact the only technological civilization in the galaxy." Stars (and the planets around them ... those planets could be Earth-like.
Unlike modern times, ancient civilizations often lacked the concept of Earth as a spherical planet among others in the solar system. Instead, their understanding revolved around their immediate ...