Which of these is NOT a contributor to librations, the "nodding" back and forth of the Moon that allows observers on Earth to see more than half of it?
A) The Moon's rotation axis is not perpendicular to its orbital plane.
B) The Moon's orbit around Earth and the ecliptic are not the same plane.
C) The Moon is not always the same distance from Earth.
D) Earth does not move at a steady rate in its orbit about the Sun.

Question

Quizplus · Accepted Answer

Librations are caused by the Moon's orbital characteristics and its orientation relative to Earth, not by the variable speed of Earth in its orbit around the Sun. Choices A, B, and C directly affect how we perceive the Moon from Earth, contributing to our ability to see slightly more than half of its surface over time.

Which of These Is NOT a Contributor to Librations, the "Nodding