Solving solar system quandaries is simple: Just flip-flop the position of Uranus and Neptune
Quick: What's the order of the planets in the solar system? Need a little help? Maybe the following mnemonic rings a bell: "My Very Educated Mother Just Served Up Nine Pizzas." It's useful for remembering the order of the planets today, but it wouldn't have been as useful in the past, and not just because the International Astronomical Union demoted Pluto to "dwarf planet" last year. The reason this mnemonic wouldn't have worked is because the planets weren't always in the order they are today. Four billion years ago, early in the solar system's evolution, Uranus and Neptune switched places.