This is a reflective, end-of-year historical deviation. From wandering stars and stubborn philosophers to lost planets, national rivalries, and Pluto’s demotion, this episode explores how we learned what the planets are and why the process matters as much as the answer.

You see every once in a while, Whimsical Wavelengths takes a historical deviation. This is one of those episodes.

Instead of cutting-edge research, this solo episode steps back to ask a bigger question: how did we actually figure out what the planets are, and what does that process tell us about how science works?

From the wandering lights tracked by Babylonian astronomers over 3,000 years ago, to Greek ideas of moving stars, to the long-lived geocentric universe of Ptolemy, we trace how humanity slowly built models of the solar system. Along the way, we ...