PART I Understanding Astronomy
Discovering the Night Sky
WHAT IF . . . Earth’s Axis Lay on the Ecliptic?
Gravitation and the Motion of the Planets
Light and Telescopes
WHAT IF . . . Humans Had Infrared-Sensitive Eyes?
Atomic Physics and Spectra
PART II Understanding the Stars
The Sun: Our Extraordinary Ordinary Star
Characterizing Stars
The Lives of Stars from Birth Through Middle Age
WHAT IF . . . The Earth Orbited a 1.5 M Sun?
The Deaths of Stars
WHAT IF . . . A Supernova Exploded Near Earth?
Black Holes: Matters of Gravity
PART III Understanding the Universe
The Milky Way Galaxy
Galaxies
WHAT IF . . . The Solar System Were Located Closer to the Center of the Galaxy?
Quasars and Other Active Galaxies
Cosmology
PART IV Understanding the Solar System
Formation of the Solar System and Other Planetary Systems
Earth and Moon
WHAT IF . . . The Moon Didn’t Exist?
The Other Terrestrial Planets
The Outer Planets
WHAT IF . . . We Lived on a Metal-Poor Earth?
Vagabonds of the Solar System
Astrobiology