To measure the parallax of the most distant stars measurable, we would make two measurements of the star's position on the sky separated by:
A) 6 hours
B) 12 hours
C) 24 hours
D) 6 months
E) 12 months

Question

Quizplus · Accepted Answer

To measure the parallax of distant stars, we need to measure their apparent shift against the more distant background stars. This apparent shift is caused by the change in the position relative to Earth as it moves around the Sun in its orbit. Therefore, we need to observe the star's position at two different times when the Earth is on opposite sides of its orbit around the Sun, which takes approximately 6 months or half of a year. Therefore, the best choice is D - 6 months.

To Measure the Parallax of the Most Distant Stars Measurable