What is the baseline that astronomers use to measure the parallax (the distance) of the nearest stars?
A) the diameter of the Earth
B) the distance between observatories in Greenwich, England and Washington, DC
C) the distance between the Earth and the Moon
D) ½ the diameter of the Earth's orbit around the Sun
E) no one can measure parallax for the stars; only for planets in our solar system

Question

Quizplus · Accepted Answer

The baseline that astronomers use to measure the parallax of the nearest stars is ½ the diameter of the Earth's orbit around the Sun. This is because the Earth's position changes as it orbits the Sun, providing two different points of view for observing the star's apparent shift in position. This allows astronomers to calculate the distance to the star using trigonometric principles.

What Is the Baseline That Astronomers Use to Measure the Parallax