By the term universe, astronomers mean
A) the system of the Sun, its planets and moons, and small pieces of debris that surround it
B) the system of 200 to 400 billion stars, of which the Sun is one
C) the collection of several dozen galaxies, of which the Milky Way is one
D) everything that we can observe
E) the realm inside the atom

Question

Quizplus · Accepted Answer

The term universe refers to everything that we can observe, including all the matter and energy that exists. A, B, C, and E refer to different subsets of the universe.

By the Term Universe, Astronomers Mean