Astrophysics in a Nutshell

Citation

Maoz, D. (2016). Astrophysics in a Nutshell (2nd ed.). Princeton University Press.

Chapter Summary

The second edition runs to 312 pages: a preface, a page of constants and units, ten chapters, an appendix and an index, with a set of problems at the end of each chapter. Princeton University Press describes it as a brief but thorough introduction for advanced undergraduate science majors to the observational data and theoretical concepts behind modern astronomy, emphasizing the physical principles shared by astronomical phenomena and the interplay between theory and observation. The edition adds a new chapter on extrasolar planets and a greatly expanded chapter on the interstellar medium. The summaries below follow the section headings in the publisher's table of contents.

Chapter 1: Introduction

A short opening chapter with a single section, on observational techniques.

Chapter 2: Stars: Basic Observations

Reviews blackbody radiation, then covers the measurement of stellar parameters and the Hertzsprung–Russell diagram.

Chapter 3: Stellar Physics

The longest chapter by section count (twelve sections). It builds the structure of a star from its parts: hydrostatic equilibrium and the virial theorem, mass continuity, radiative energy transport, energy conservation, the equations of stellar structure, the equation of state and opacity. It then turns to scaling relations on the main sequence, nuclear energy production and reaction rates, the solution of the structure equations and convection.

Chapter 4: Stellar Evolution and Stellar Remnants

Stellar evolution is followed by white dwarfs, supernovae and neutron stars, pulsars, black holes and interacting binaries.

Chapter 5: Star Formation and the Interstellar Medium

Cloud collapse and star formation, H II regions, the components of the interstellar medium, and shocks, supernova remnants and cosmic rays. The publisher says the second edition expands the treatment of shocks, supernova remnants and cosmic-ray acceleration.

Chapter 6: Extrasolar Planets

New in this edition: planet detection methods, the occurrence and architecture of planetary systems, planet formation and evolution, and habitable zones and the search for life.

Chapter 7: The Milky Way and Other Galaxies

The structure of the Milky Way, galaxy demographics, active galactic nuclei and quasars, and groups and clusters of galaxies.

Chapter 8: Cosmology: Basic Observations

The Olbers paradox, extragalactic distances, Hubble's law, the age of the universe from cosmic clocks and the isotropy of the universe.

Chapter 9: Big Bang Cosmology

The Friedmann–Lemaître–Robertson–Walker metric and the Friedmann equations, the history and future of the universe, a Newtonian derivation of the Friedmann equations, and dark energy and the accelerating universe.

Chapter 10: Tests and Probes of Big Bang Cosmology

Cosmological redshift and Hubble's law, the cosmic microwave background and its anisotropy, baryon acoustic oscillations, nucleosynthesis of the light elements, and quasars and other distant sources as cosmological probes.

Key Concepts

Chapters 2–4: Stars

• Hertzsprung–Russell diagram: the observed relation among stellar parameters introduced in Chapter 2.
• Equations of stellar structure: hydrostatic equilibrium, mass continuity, energy transport and conservation, with an equation of state and opacity.
• Stellar remnants: white dwarfs, neutron stars and pulsars, and black holes.

Chapters 5–7: Gas, planets and galaxies

• Interstellar medium and star formation: H II regions, shocks, supernova remnants and cosmic rays.
• Planet detection and habitability: Chapter 6.
• Active galactic nuclei and quasars: Chapter 7.

Chapters 8–10: Cosmology

• Friedmann equations: presented in Chapter 9 after the FLRW metric, with a separate Newtonian derivation.
• Dark energy and acceleration: Chapter 9.
• Cosmological probes: the microwave background, baryon acoustic oscillations and light-element nucleosynthesis.

Critical Analysis

Strengths

• Concise by design. The publisher calls it the most concise and current astrophysics textbook for science majors, with simple, short, clear derivations. Reviewers of the first edition describe a focused, fast-paced text: Greg Laughlin said it covers the widest range that can reasonably fit in one serious semester, and K. L. Schick, in Choice, found a great deal of material squeezed into a thin volume.
• Order-of-magnitude skills. The publisher lists training in order-of-magnitude analysis as a feature, and Schick praised the back-of-the-envelope calculations that illustrate the physics and give decent numerical answers.
• A physical treatment of stars. The twelve sections of Chapter 3 give the structure and energy of stars a full derivation. Schick called the treatment of stellar physics particularly insightful, and Leon Mestel, in The Observatory, noted the balance between mathematical discussion and physical argument.
• Problems and recognition. Each chapter ends with problems; the book won the American Astronomical Society's Chambliss Award and was named one of Choice's Outstanding Academic Titles for 2016.

Limitations

• Narrow observational base. The introduction holds a single section on observational techniques, and the table of contents has no chapter on the Sun or the solar system; readers who need either will need a broader survey.
• Compressed treatments. With ten chapters in 312 pages, topics such as extrasolar planets (four sections) and the interstellar medium receive an introduction rather than a full account.
• Solutions are restricted. The publisher offers a solutions manual only to professors, so self-study readers have no worked answers to the problem sets.
• Reviews cited are for the first edition. The quoted praise refers to the first edition; the second edition adds new material (planets, expanded interstellar medium, new problems and updated figures) that the reviewers did not assess.

Where It Fits in the Course

In the astrophysics and cosmology list, Maoz is the compact one-semester text for upper-level science majors. Two books sit below it: OpenStax's Astronomy 2e is an introductory astronomy text with little mathematics, and Binney's Astrophysics: A Very Short Introduction concentrates on physical processes for readers without advanced mathematics. Either can supply the descriptive background that Maoz's one-section introduction does not.

At a similar level, Carroll and Ostlie's An Introduction to Modern Astrophysics is a comprehensive calculus-based survey that also begins from observational foundations and the solar system and works well as a reference; Liddle's An Introduction to Modern Cosmology is a short text on Big Bang cosmology that uses Newtonian arguments wherever they suffice and can serve as a second source on the material of Chapters 8–10. For graduate study, Dodelson and Schmidt's Modern Cosmology derives the Boltzmann and Einstein equations for perturbations and applies them to the microwave background, galaxy clustering and lensing.

How to Use This Book

The book is for advanced undergraduates in physics or astronomy who have taken calculus-based mechanics, electromagnetism, thermodynamics and an introduction to modern physics; no prior astronomy course is needed.

A practical plan for a semester:

• Stars (Chapters 2–4): the core of the course; Chapter 3 is the most demanding and rewards working through the structure equations by hand.
• Interstellar medium and planets (Chapters 5–6): short chapters that can be covered quickly or chosen between according to the course.
• Galaxies and cosmology (Chapters 7–10): read Chapters 8, 9 and 10 in order, as the observations in Chapter 8 are the basis for the Friedmann equations in Chapter 9 and the tests in Chapter 10.
• Problems: work the end-of-chapter problems, which build the order-of-magnitude habit; because worked solutions are not available to students, compare answers with classmates or a course instructor.
• Review: the publisher recommends it as a review for qualifying exams and as a reference for teachers and researchers.