Earth Space Honor Mid-Term Exam Study Guide

2012-2013Questions 1-11

8. How do the distances between planets, solar systems, galaxies and the universe compare?

9.Compare the sizes of planets, solar systems, galaxies, and the universe.

10.Compare the composition of planets in our solar system.

10. Compare the composition of planets in our solar system.

11. What are some of the different galaxies in our universe and how do their size and composition

compare to each other?A galaxy is a large

collection of stars, gas and dust held together by

the force of gravity. Galaxies range in size

from dwarf galaxies with approximately 100 million

stars, to giant galaxies with approximately 1

trillion stars. There are three basic types of

galaxies – spiral, irregular and elliptical.

Our solar system is part of the Milky Way galaxy,

a spiral galaxy.