What is unique about the Pluto-Charon system, compared with all other planets and dwarf planets in the solar system?
A) Both Pluto and Charon are volcanically active, with lava flows and vents of sulfur dioxide gas.
B) Charon is an icy moon, but it is in orbit around a giant planet made mostly of liquid hydrogen.
C) Pluto has only one satellite.
D) Both Pluto and Charon are in synchronous rotation, so each object maintains the same face toward the other object at all times.

Question

Quizplus · Accepted Answer

Pluto and Charon are unique in the solar system because they are in synchronous rotation with each other, meaning they always show the same face to each other. This is not observed in any other planet-moon system in the solar system.

What Is Unique About the Pluto-Charon System, Compared with All