Book excerpt: An astronomer brings the mysteries of space down to earth in this accessible guide to cosmology, astrophysics, and the ageless wonder of the night sky. The universe is big. Really big. And it gets bigger every day. In Cosmological Enigmas, Mark Kidger weaves together history, science, and science fiction to consider questions about the bigness of space and the strange objects that lie trembling at the edge of infinity. What are quasars, blazars, and gamma-ray bursters? Could we ever travel to the stars? Can we really expect aliens to contact us? From the profound (what evidence do we have to support the big bang theory?) to the bizarre (can there be more than one universe and, if so, how many dimensions does it possess?) to the everyday-yet-profound (why is the sky dark at night?), Kidger explains not only what we know about the universe but how we came to know it. Reflecting on how stars shine and what may lie beyond the edge of the universe, Kidger takes us on the ultimate cosmic journey.