Asteroid Impostors and the Planet that Never Was: What’s on Your Diagram of the Solar System?

Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, and Neptune: These are the eight planets of the solar system displayed on diagrams in our educational resources today. Of course, many of us still remember Pluto, which was considered a planet for many years until it was recently reclassified. Pluto’s demotion isn’t the only dramatic change that’s happened to educational solar system diagrams over the years, though.