Origins -- The size of the universe -- A brief history of the universe -- Heliocentric universe -- The expanding universe -- Big bangs and steady states -- Other universes -- How it may end -- Studying space -- Optical telescopes -- Electromagnetic spectrum -- Measuring distances in space -- Worlds beyond planets of other suns -- Seti -- The solar system -- A solar system -- Birth of a solar system -- Orbits -- Types of orbiting bodies -- What are stars made of? -- What are planets made of? -- What are moons made of? -- The sun -- The moon -- The surface of the moon -- Eclipses -- Comets -- The planets of our solar system -- How much would I weigh on...? -- Stars and constellations -- What is a star? -- Life cycle of a star -- Element factories -- Distances to the stars -- The constellations -- Star magnitudes -- Star companions -- Nebulae -- Death of a star -- Going supernova -- The stuff of the universe -- What is the universe made of? -- Antimatter -- The forces of nature -- The search for dark matter -- Looking at galaxies -- What is a galaxy? -- The Milky Way -- Our intergalactic neighbors -- Types of galaxies -- When galaxies collide -- Space exploration -- How rockets work -- Von Braun and the V2 -- Korolyov and the Soviets -- Timeline of rocketry and space exploration -- The space race -- Vostok -- Mercury -- Project gemini -- The Apollo Program -- Space stations -- The space shuttle -- Satellites -- Probes.