Question

How can astronomers be sure that their measurements of distances to galaxies are accurate?

A. Modern measurements match distances measured by ancient people
B. They measure the distance using multiple independent methods
C. They get the same results when they repeat the same experiments
D. The distances look about right given the size of the galaxies in our night sky

Answer 1

Astronomers can be sure that their measurements of distances to galaxies are accurate by using multiple independent methods to measure the distance.

Step-by-step explanation:

Astronomers can be sure that their measurements of distances to galaxies are accurate by using multiple independent methods to measure the distance. This is option B. By using different techniques, astronomers can cross-validate their measurements and ensure accuracy. For example, astronomers can measure distances using parallax, the apparent shift in position of a star when viewed from different locations. They can also use the redshift of galaxies, which is a shift in the wavelength of light emitted by galaxies due to their motion away from us. These methods provide a way to independently verify the distances measured, increasing the confidence in their accuracy.