In order to calculate the size and luminosity of a galaxy, you must first determine its ____.
A) age
B) mass
C) shape
D) metallicity
E) distance

Question

Quizplus · Accepted Answer

The size and luminosity of a galaxy can be accurately calculated only if its distance from us is known. Distance provides a baseline for measuring true size and brightness, as apparent size and brightness can be misleading without knowing how far away the galaxy is.

In Order to Calculate the Size and Luminosity of a Galaxy