Earth (Life Nature Library)

This is a journey to the earth. It begins far out in the immeasurable universe, within a cluster of galaxies that are huddled together in what astronomers call a Local Group. One member of this cosmic family, itself made up of countless stars, has a graceful, pinwheel-like form. This is the Milky Way; as galaxies go, it is only of fair-to-middling size, yet its dimensions are numbing to the mind.