What is the angle between the line from Earth to Mercury and the line from Mercury to the Sun when Mercury is at greatest elongation?
A) 90°
B) 180°
C) anywhere between 0° and 180°, depending on the particular planetary alignment
D) 0°

Question

Quizplus · Accepted Answer

At greatest elongation, the angle between the line from Earth to Mercury and the line from Mercury to the Sun is 90°. This is because greatest elongation occurs when Mercury appears farthest from the Sun in the sky, which geometrically corresponds to a right angle from our viewpoint on Earth.

What Is the Angle Between the Line from Earth to Mercury