When a formal definition of a planet in the solar system was adopted, Pluto was reclassifiedas a dwarf planet. What characteristic of planets does NOT describe Pluto?
A)Planets orbit the Sun.
B)Planets are approximately spherical.
C)Planets have cleared the neighborhood around their orbit.
D)Planets orbit in ellipses with low eccentricity.
E)Planets orbit in or very near the ecliptic plane.

Question

Quizplus · Accepted Answer

One of the characteristics of planets is that they have cleared the neighborhood around their orbit. Pluto has not done so, as it shares its orbit with other dwarf planets and objects in the Kuiper Belt. Therefore, the characteristic that does not describe Pluto is that it has cleared the neighborhood around its orbit. Pluto has not cleared the neighborhood around its orbit, which is a requirement for a celestial body to be considered a planet according to the formal definition adopted by the International Astronomical Union.

When a Formal Definition of a Planet in the Solar