An Inferior Planet Moves More or Less Directly Toward Earth

question 161

Multiple Choice

An inferior planet moves more or less directly toward Earth at greatest eastern elongation.What does this mean when you are watching the night-by-night motion of this planet against the background stars?

• A) The planet appears to remain stationary for a few days.
• B) The planet appears to be moving at its fastest motion against the background.
• C) The planet is invisible in the sky because it is moving toward Earth.
• D) The planet's motion against the background will appear to be normal, that is, direct motion, because apparent motion is always constant in a circular orbit.