A simile is a figure of speech that directly compares two things through some connective, usually like, as, than, or a verb such as resembles.. A simile differs from a metaphor in that the latter compares two unlike things by saying that the one thing is the other thing.
A galaxy is an enormous collection of gas, dust and billions of stars held together by gravity. One galaxy can have hundreds of billions of stars and be as large as 200,000 light years across.
SPIRAL GALAXIES - A galaxy that has a distinct nucleus and one or more spiral arms. The arms extend outward from the nucleus and are composed of stars, dust, and gas. Population I stars are found in the arms and Population II in the nucleus, between arms and probably in the halo. Population I are considered younger stars.