0 In Astronomy

Why isn’t Pluto a planet?!?!?

Ahhhhh sweet cute innocent little Pluto, what did you do to deserve the demotion? How can we live in a world with only 8 planets? Were all those years of elementary school for nothing?
Many people have an attachment to Pluto which is what makes its demotion one of the most common questions I get. I hate to burst your bubble but NASA is right. Pluto is not a planet, but, trust me, it is still special!

Why was Pluto ever considered a planet?

KuiperbeltBack in the early 1900’s when Pluto was discovered, it was the first object discovered in what is referred to as the Kuiper Belt. Because astronomers didn’t know about the rest of the objects in the Kuiper Belt, Pluto was thought of as unique. As modern science progressed, numerous objects have been discovered in the Kuiper Belt. Yet, Pluto held onto its rank as a planet because of its rare spherical shape.

However, as time went on, astronomers could not ignore the findings of multiple spherical objects in the Asteroid Belt and the Kuiper Belt. They had to make a choice. Open up the floodgates to possibly a multitude of new planets (three additional at the time) or demote Pluto. Unfortunately for the many devout Pluto lovers, it was the latter. The final criterion in the definition of planet is that the object must dominate its neighborhood and thus can’t exist in the Asteroid Belt and Kuiper Belt.

WAIT WAIT WAIT a second… don’t get too sad! I promised Pluto is still special for not one but two reasons!

  1. Pluto, although demoted from planet, does hold the rank of dwarf planet with those other spherical objects.
  2. Pluto is also a transneptunian object. It is one of a few unique objects that leave the Kuiper Belt and cross into Neptune’s orbit.

So don’t worry Pluto can always be your favorite! You just have to go by its two new names instead of planet….. or keep calling it a planet as much of the internet insists 😉
Photo by NASA

You Might Also Like

No Comments

Leave a Reply