The above represents the number of planets in our solar system over time. This is something I was thinking about the other day. Depending on how you define something, data that you might expect can only go one way sometimes goes in another direction.
From the Sumerians discovering Venus, to the Babylonians, the sun and moon defined as planets, to the modern understanding of the solar system, and ending in the decision to cull Pluto from the list in favour of defining it, amongst others, as “minor planets”.
