Solution Q.1.

Why is trigonometric parallax only suitable for measuring the distance to relatively close stars?

A. The angles measured are very small.
B. Distant stars are outside the Milky Way.
C. Distant stars are moving faster than close stars.
D. As distance increases, there are less background stars to measure against.


Answer: A

The further a star is away from Earth the less is its angle of trigonometric parallax.
Since the very small angles involved (fractions of a second) are hard to measure the degree of accuracy decreases the further a star is away from Earth.


Back to Q1
Move on to Q2