早年的希臘科學家藉由觀察天上星體運行的軌跡,來了解太陽系中,眾星球之間的相對位置和運動。當他們觀測到火星大約每兩年會有一次逆行,都感到很困惑。為什麼行星會有這種逆行現象呢? To understand planetary positions and movements in the Solar System, early Greek scientists studied the path of planets in our sky. When they noticed that Mars traveled backwards every 2 years or so, they were puz...