If the distance between Earth and a star is measured using parallax measurements, how far apart in time should the two measurements be made to make the parallax measurement as accurate as possible?
A) instantaneously
B) a day
C) six months
D) a year

Question

Quizplus · Accepted Answer

Parallax measurements are most accurate when taken six months apart because this is when Earth is on opposite sides of its orbit around the Sun, maximizing the baseline distance and thus the parallax angle.

If the Distance Between Earth and a Star Is Measured