Kudo planet or not before we can answer this question we need to know what the word planet is for and that takes us back to the ancient Greeks who called Mercury Venus Mars Jupiter Saturn the moon and the Sun planets basically if it moved across the sky and was bright it was a planet this is a terrible start.
For the word because one it excludes Earth from the list and two it groups wildly different things together but.
The Greeks couldn’t know how different the moon was from Saturn because the best technology they had to observe the universe was sadly limited it would take several thousand years until the industrious Dutch.
And astronomy became much more.
Interesting astronomers can now confidently rearrange the solar system and elegant scientific advance that no one could possibly object to and reclassify its parts dropping the Sun and the moon from the list of planets and adding earth now if it orbited the Sun it was a planet as time went on and telescopes got.
Better and better each new century brought with it the discovery of a new planet which brings us to this familiar solar.
System nine planets orbiting one star looking at this model makes people.
Wonder why do astronomers want to ditch Pluto the problem is pictures like this in textbooks our lives well not lies exactly but unhelpful they.
Give the impression that the planets are similar ition sized and evenly ish spaced but the reality couldn’t be more different here dear Terrans is our home planet Earth and this is Jupiter next to.
It at the correct scale rather bigger than you probably thought if we take this diagram and adjust for the correct sizes of the planets it looks like this unless you’re watching the video in full-screen HD mode you might not be even able to see Pluto so size differences are vast and Pluto is the smallest by far but it’s not just small for a planet it’s.
Also smaller than nine moons Triton Europa our own moon Io Callisto Titan and Ganymede even if you show the correct relative sizes the distances are still a problem think about it if Jupiter was this close to Earth it wouldn’t look like a.
Dot in the night sky but would be.
Rather overwhelming so it must be really far away which makes drawing it to scale rather a challenge if you want the length of a piece of paper to represent the distance from Mercury to Pluto and giant Jupiter would.
Be the size of a dust mite on that page and Pluto a bacterium but excluding Pluto from the planet club just for being tiny and small isn’t reason enough and quickly brings out the Pluto defenders in order to understand what Pluto.
First discuss a planet you’ve never heard of series back in 1801 astronomers found a new in the huge gap between Mars and Jupiter it was a small planet but they loved it anyway and named it Ceres the next year astronomers found another small planet in the same area and.
Named it Pallas a few years later they found a third one Juno and then funnily enough a fourth one Vesta and for several decades children learned the 11 planets of the solar system but astronomers kept finding more and more of these objects and became increasingly uncomfortable calling them planets because they.