Contents
- Preface
1Science and the Universe: A Brief Tour
2Observing the Sky: The Birth of Astronomy
7Other Worlds: An Introduction to the Solar System
13Comets and Asteroids: Debris of the Solar System
14Cosmic Samples and the Origin of the Solar System
18The Stars: A Celestial Census
20Between the Stars: Gas and Dust in Space
21The Birth of Stars and the Discovery of Planets outside the Solar System
27Active Galaxies, Quasars, and Supermassive Black Holes
- AHow to Study for an Introductory Astronomy Class
- BAstronomy Websites, Images, and Apps
- CScientific Notation
- DUnits Used in Science
- ESome Useful Constants for Astronomy
- FPhysical and Orbital Data for the Planets
- GSelected Moons of the Planets
- HFuture Total Eclipses
- IThe Nearest Stars, Brown Dwarfs, and White Dwarfs
- JThe Brightest Twenty Stars
- KThe Chemical Elements
- LThe Constellations
- MStar Chart and Sky Event Resources
- Index
Review Questions
Review Questions
Describe some differences between quasars and normal galaxies.
Describe the arguments supporting the idea that quasars are at the distances indicated by their redshifts.
In what ways are active galaxies like quasars but different from normal galaxies?
Why could the concentration of matter at the center of an active galaxy like M87 not be made of stars?
Describe the process by which the action of a black hole can explain the energy radiated by quasars.
Describe the observations that convinced astronomers that M87 is an active galaxy.
Why do astronomers believe that quasars represent an early stage in the evolution of galaxies?
Why were quasars and active galaxies not initially recognized as being “special” in some way?
What do we now understand to be the primary difference between normal galaxies and active galaxies?
What is the typical structure we observe in a quasar at radio frequencies?
What evidence do we have that the luminous central region of a quasar is small and compact?