Gravity is what keeps us from flying off into space. We are always being pulled towards the center of the earth. The moon is also pulled by the earth's gravity. That''s why it''s always so close to us.
Author Biography
Robin Nelson's careers have always kept her surrounded by books--as an elementary teacher, working at a publishing company, and now working as a school library media specialist. But her favorite job is writing books for kids. She has written many nonfiction books for children. She lives with her family in Minneapolis.
