Question

Why is Pluto no longer a planet?

Answer 1

The International Astronomical Union (IAU) downgraded the status of Pluto to that of a dwarf planet because it did not meet the three criteria the IAU uses to define a full-sized planet. Essentially Pluto meets all the criteria except one—it “has not cleared its neighboring region of other objects.

Answer 2

Scientist thought it was to small to be a planet.

Step-by-step explanation:

it's sad, it was my favorite planet. now it's my favorite dwarf planet.