Please use complete sentences and clearly indicate which part of the question yo
ID: 110828 • Letter: P
Question
Please use complete sentences and clearly indicate which part of the question you are referring to.
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S uppose you observe Mars at midnight, and it is due South from where you are. Which of the following statements is or are false, and what is wrong with the false statement(s)?
(a) Mars is exhibiting retrograde motion around the date of your observation.
(b) Mars would appear as a crescent if viewed through a telescope at this time.
(c) Mars is farther from the earth at the time of your observation than it usually or on average is.
Explanation / Answer
The statements can't be true because When Mars is at "opposition" it means that the planet is on the opposite side from the Sun. So it rises in the East just after sunset and sets in the West just before sunrise, and at midnight standard time it should be due South for observers in the Northern hemisphere. All superior planets will be moving retrograde in the Earth's sky when they are at opposition, including Mars, and they will be at "full" phase, just as the Moon is at full phase when it is opposite the Sun. Planets move retrograde when they are at opposition because the Earth's orbital velocity is faster than any of them, so they seem to be moving backwards..............