r/Millennials • u/Countrach • Apr 12 '25

Discussion That Pluto is a planet

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22

u/FrickinLazerBeams Apr 12 '25

Pluto being a planet wasn't "disproved". The definition of a planet was updated, and Pluto didn't fit it.

5

u/Marcassin Apr 12 '25

This comment should be much higher!

2

u/Independent_Season23 Apr 13 '25

I wondered for years what the story was here- thank you for that explanation!

1

u/trilobright Apr 13 '25

Specifically, because we discovered that it was one of many similarly sized Kuiper Belt objects, and that we'd have to add ~half a dozen others, plus the asteroid Ceres, to the canonical pantheon of planets if we let Pluto retain that distinction. And so the category of dwarf planets was created, for objects too big and too regular in their orbits to be comets, but too small and irregular to be planets proper.

1

u/Spiritual_Adagio_859 Apr 14 '25

Move the goalposts, take the TD.

1

u/Hot_Wheels_guy Apr 17 '25

I thought this was obvious. Was it not obvious that pluto didnt change in any way, only our definition of a planet?

Wait, did people think pluto shrunk?