He described how the earth orbits around the sun and how the sun, in turn, orbits around the center of a vast A brief history of time: Hawking, Stephen, Free Download, Borrow, and Streaming: Internet Archive Black Holes and Baby Universes and Other Essays. ChapterOur Picture of the Universe ChapterSpace and Time ChapterThe Expanding Universe ChapterThe Uncertainty Principle ChapterElementary Particles and the Forces of Nature ChapterBlack Holes ChapterBlack Holes Ain't So A Brief History of Time