Question

question 2
why did pluto get \demoted\ to the dwarf planet category?
pluto didnt match the other planets in size.
astronomers found other fairly large kbos, similar in size & composition to pluto.
the new horizons mission to pluto revealed that it is not a planet, after all.
some astronomers wanted to play a practical joke on neil degrasse tyson. once he let the general public know about plutos \demotion\, he started getting hate mail from 8 - year - olds!

Explanation:

Pluto was re - classified as a dwarf planet because astronomers discovered other large Kuiper Belt Objects (KBOs) similar to Pluto in size and composition, which led to a re - evaluation of what constitutes a planet. The new definition of a planet required it to clear its orbit of other similar - sized objects, and Pluto did not meet this criterion.

Answer:

Astronomers found other fairly large KBOs, similar in size & composition to Pluto.