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SpaceBook Chapter 5 Galaxies

Our Sun is one of at least 100 billion stars in the Milky Way galaxy. The universe contains billions of galaxies, each with millions or billions of stars. Galaxies vary in shape and size, and they interact with each other, sometimes crashing into each other and merging, sometimes tearing each other apart. This chapter describes galaxies, their history of discovery and their types and classification.

Image credit: Alice Hopkinson, LCO