Question

Why can we not determine distances to galaxies by the same method used to measure the parallaxes of stars?

Answer 1

Parallaxes can be measured accurately out to distances of approximately 100 light-years. The nearest galaxies are about 50,000 to 80,000 light-years from the Sun. Therefore, there is no perceptible change in the apparent position of any galaxy as we view it from opposite sides of Earth's orbit.