Galaxies

Galaxies — page 3
CHAPTER 1 WHAT IS A GALAXY A galaxy is a huge group of stars gas dust and planets held together by gravity There are three main types of galaxies They are spiral elliptical and irregular Most galaxies seen from Earth are spiral galaxies A spiral galaxy has a dense bulge of stars at its center More stars spiral out like long arms This gives the galaxy a pinwheel shape Newer stars are found in a spiral galaxy's outer arms Older stars are closer to the center A barred galaxy is a type of spiral galaxy A bar shaped group of stars spans the center of each barred galaxy More stars spiral out from this bar The Milky Way galaxy is barred Scientists believe about one third of spiral galaxies are barred