Astronomy is the scientific study of the universe as a whole, and of celestial bodies and the underlying physics governing these bodies. It is in some sense one of the oldest of the natural sciences, having been practiced by even very ancient civilizations, but it is also among the most modernized of the sciences, having extensively exploited both advances in technology and the rise of space exploration. The progress of technology has dramatically improved our understanding of the universe, revealing a richer tapestry than had ever been imagined before. This wikibook introduces the advanced secondary or beginning university student to that tapestry and the process that revealed it to humanity, presenting astronomy not only as a field of knowledge, but also as a human endeavor in science.

Table of Contents

1. The Modern View of the Cosmos
   1. The Big Picture
   2. Short History of the Universe
   3. Scientific Notation
   4. The Scientific Method
   5. What People do in Astronomy
   6. Current Unsolved Mysteries
2. Observational Astronomy
   1. The Celestial Sphere
   2. Phases of the Moon
   3. Eclipses
   4. Daily Motions
   5. Yearly Motions
   6. Coordinate Systems
3. Motion and Gravity
   1. The Early Origins of Astronomy
   2. The First Physics (Aristotle)
   3. Difficulties in the Geocentric Model
   4. The Heliocentric Model (Copernicus)
   5. New Ideas About Motion (Galileo)
   6. Order in Planetary Orbits
   7. The Theory of Gravity Matures
4. Principles of Light
   1. What is Light?
   2. The Spectrum
   3. Basic Astrophysics
   4. Atomic Emission and Absorption
   5. Molecular Emission and Absorption
   6. Thermal Radiation
   7. The Doppler Effect
   8. Optics and Telescopes
5. Planetary science
   1. The Terrestrial Planets
   2. The Jovian Planets
   3. Comets
   4. Asteroids
   5. Meteors and Meteorites
   6. The Kuiper Belt
   7. Extrasolar Planets
   8. Formation of the Solar System
6. Earth as a Planet
   1. Earth's Early Years
   2. Formation of the Moon
   4. The Atmosphere
   6. Earth
   7. Earth's Moon
7. Space Exploration
   1. First Steps into Space
   2. The Apollo Missions
8. Astrobiology and Extraterrestrial Life
   1. The Drake Equation
   3. Life in the Solar System
   4. The Search for Extraterrestrial Intelligence
9. The Sun
   1. Fusion in the Sun
   3. The Photosphere
   4. Solar Activity
   7. The Solar Cycle
10. Stars
    1. Mass
    2. Luminosity
    3. Temperature
    4. The H-R Diagram
    5. Star Clusters as Cosmic Laboratories
11. The Stellar Life Cycle
    1. Protostars and Stellar Nurseries
    4. The Life of High Mass Stars
12. Black Holes
    1. Life of the Black Hole
    4. Core of the Black Hole: The Theory of the Naked Singularity
13. Galaxies
    1. The Milky Way
    2. Types of Galaxies
    3. Galactic Formation
14. Cosmology
    2. The Big Bang and Cosmic Expansion
    4. An Accelerating Universe

References

Exercises

Also on Wikimedia

Wikibooks is a Web site where this and other free textbooks are developed. In addition to this book, Wikibooks is the host of related textbook projects.

• General Relativity, an advanced undergraduate treatment of the principles of general relativity
• Astrophysics, a textbook for beginning students in physics and astronomy
• Astrodynamics
• Wikijunior Solar System, a children's nonfiction book about the Solar System

Wikipedia is a free online encyclopedia. To find information about astronomy at Wikipedia, start at the astronomy portal

Wikiversity has, or is developing, course material around Astronomy.