Question

Why is Pluto called a dwarf planet ?

Answer 1

Pluto is a dwarf planet because it is not big enough to be a major planet there are other dwarf planets in our solar system, too.

Answer 2

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.”