For what reason was Pluto demoted from full planetary status in 2006?
A)Because of objects as large or larger than Pluto in the Kuiper belt
B)Because Pluto resides outside of the zone that can truly be described as the solar system
C)Because Pluto was discovered to be a twin planet system
D)Because according to the standard definition, no planet can be smaller than the Earth's moon

Question

Quizplus · Accepted Answer

Pluto was demoted from full planetary status in 2006 because objects as large or larger than Pluto were being discovered in the Kuiper belt, leading the International Astronomical Union to redefine what constitutes a planet. Under the new definition, Pluto did not meet the criteria to be considered a full planet.

For What Reason Was Pluto Demoted from Full Planetary Status