# Course Descriptions
**Source**: https://astronomy.fas.harvard.edu/course-descriptions
**Parent**: https://astronomy.fas.harvard.edu/undergraduate-program
[Courses mainly aimed at non-concentrators](/course-descriptions#non-concentrators)\
[Introductory courses for concentrators and secondaries](/course-descriptions#concentrators)\
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### Courses mainly aimed at non-concentrators
### Astronomy 1: The Big Questions of Astronomy
Instructor: Edo Berger (Fall 2025), Morgan MacLeod (Spring 2026)
Offered: Fall and Spring
Description: We will discuss the big questions of astronomy that have engaged scientists and the general public alike for centuries: How did the universe begin? What is the ultimate fate of the Sun? How do planets form? Is there life outside the Solar system? Students will use telescopes to study the night sky and examine how the combination of astronomical observations and physical theory have led to an understanding of the vast and dynamic cosmos we inhabit.
## Astronomy 2: Celestial Navigation
Instructor: Philip Sadler\
Offered: Fall semesters
Description: Never be lost again! Find your way on sea, land, or air by employing celestial and terrestrial techniques. Acquire expertise in using navigators' tools (sextant, compass, and charts) while learning the steps to the celestial dance of the sun, moon, stars, and planets. This 108-year-old course continues to rely on practical skills and collaborative problem-solving, while utilizing historical artifacts (instruments, maps, captains' logs) and student-built devices. Culminating in a day-long cruise to practice navigation skills.
## Astronomy 5: Astrosociology
Instructor: Gerhard Sonnert\
Offered: Spring semesters
Description: In an age of magnificent astronomical progress and discoveries, the increasing knowledge of the cosmos has manifold repercussions in society and culture. This course will examine how outer space-related phenomena impact, or potentially impact, society and culture, and vice versa. Especially in light of the proliferating discovery of exoplanets, an intriguing topic of astrosociology is presented by the possibility of the existence of extraterrestrial civilizations, their detection, communication with them, and even contact.
## Astronomy 10: How Shall We Learn if We are Alone in the Universe?
Instructor: David Charbonneau\
Offered: Spring semesters
Description: Do there exist inhabited worlds other than our own? This question has inspired thinking and observation for centuries, but there are reasons to think we may soon have the tools and understanding to reach an answer. This course will begin with a study of the 14 billion year path from the Big Bang to the origin of the chemical elements and the formation of planets. We will then turn to asking what makes some worlds habitable, and others not. Finally, we will discuss different approaches to studying nearby planets and deducing whether they host life. The course will be taught in seminar format and requires no advanced knowledge of mathematics or physics.
## Astronomy 22: The Unity of Science: From the Big Bang to the Brontosaurus and Beyond
Instructor: Irwin Shapiro\
Offered:[Not currently being offered]
Description: Science is like a well-woven, ever-expanding fabric, designed to uncover Nature's secrets. This course emphasizes the strong connections between subfields of science, showing it as the never-ending and greatest detective story ever told, with evidence always the arbiter. These characteristics are exhibited in the semi-historical treatment of three main themes: unveiling the universe, the earth and its fossils, and the story of life.
## Astronomy 50: Introduction to Space Exploration
Instructor: Josh Grindlay\
Offered: Spring semesters [Not currently being offered]
Description: The 1960s were the early glory days of space exploration, driven by the space race between the U.S. and the U.S.S.R., the Apollo program, and the successful Moon landings. After this heroic decade, space exploration lost a great deal of its impetus. Yet, very recently, there are clear signs of a reemerging dynamic in space exploration, now characterized by both the emergence of new players and new fields of exploration. This course introduces the students to a comprehensive array of diverse topics. These range from the history and sociology of space exploration to space law and space policy, from the space economy to the physical, astronomical, and engineering basics of space exploration.
## Introductory courses for concentrators and secondaries
### Astronomy 16: Stellar and Planetary Astronomy
Instructor: John Johnson (odd years), Karin Öberg (even years)\
Offered: Spring semesters
Description: This course provides an introduction to the physical principles describing the formation and evolution of stars and their planetary companions. Topics include thermal radiation and stellar spectra; telescopes; energy generation in stars; stellar evolution; orbital dynamics; the Solar system; and exoplanets. This course includes an observational component: students will determine the distance to the Sun, and use the Clay Telescope atop the Science Center to study stellar evolution and detect exoplanets.
Prerequisites: Physics 15a, Physics 16, or Physical Sciences 12a. Multivariable calculus. May be taken concurrently.
### Astronomy 17: Galactic and Extragalactic Astronomy
Instructor: Christopher Stubbs\
Offered: Fall semesters
Description: This course will introduce you to the physical principles describing galaxies and the composition and evolution of the Universe. We will cover a wide range of topics from nearby galaxies to quasars to the Big Bang.The goals of the course are 1) to introduce you to the broad sweep of extragalactic astronomy and cosmology, including major concepts and common jargon, 2) to develop detailed applications of physics, particularly mechanics, to galaxies and cosmology, 3) to gain exploratory experience in observational astronomy.
Prerequisites: Physics 15a, Physics 16, or Physical Sciences 12a. May be taken concurrently.
## Thesis courses
## Astronomy 98: Research Tutorial in Astrophysics
Instructor: Morgan MacLeod\
Offered: Fall and Spring semesters
Description: This junior tutorial introduces students to research at the forefront of astrophysics, through individual research projects guided by astronomers at the Center for Astrophysics. Students meet weekly for a discussion of reading materials provided by a guest speaker, and to provide updates on their individual research projects. The course culminates in a written report and an oral presentation (open to all scientists at the CfA).
Prerequisites: Astronomy 16 or Astronomy 17
## Astronomy 99: Senior Thesis in Astrophysics
Instructor: Charles Alcock\
Offered: Fall (A) and Spring (B) semesters
Description: Individually supervised reading and research leading to the senior thesis. The Harvard-Smithsonian Center for Astrophysics is home to one of the largest groups of astronomers in the world, providing extensive opportunities for undergraduate research. Both Part A and Part B must be taken in the same academic year in order for students to receive credit. Part one of a two part series.
Prerequisites: Astronomy 98
## Upper level courses
## Astronomy 100: Methods of Observational Astronomy
Instructor: Ashley Villar\
Offered: Spring semesters
Description: In this course we will learn the basic tools of modern astronomical research, including telescopes, detectors, imaging, spectroscopy, and common software. Emphasis will be placed on both the theory behind telescopes and their use, and hands-on experience with real data. Using this basic knowledge we will analyze science-level astronomical data from a wide range of telescopes and review the basic properties of stars, galaxies, and other astronomical objects of interest. The course includes a trip to the F. L. Whipple Observatory on Mount Hopkins, Arizona, to gather data with various telescopes.
Prerequisites: Astronomy 16 or Astronomy 17
## Astronomy 110: Exoplanets
Instructor: John Johnson\
Offered: Fall semesters {not currently offered]
Description: A survey of the rapidly-evolving field of the detection and characterization of planets orbiting other stars. Topics includes proto-stellar collapse and star formation; protoplanetary disk structure; models of planet formation; methods of detecting extrasolar planets; composition and physical structure of planets; planetary atmospheres; habitable zones; greenhouse effect; and biosignatures.
Prerequisites: Astronomy 16
## Astronomy 115: Astrochemistry
Instructor: Karin Oberg\
Offered: Spring 2026
Description: This course explores the rich and often surprising chemistry that occurs in different astrophysical environments. We will trace the evolution of chemistry from its origins soon after the Big Bang to the complex organic molecules found throughout the present-day universe. Along the way, we will examine how chemical processes shape the interstellar medium, influence the formation of stars and (exo)planets, and contribute to planetary habitability. The course will also cover the astronomical observations, theoretical models, and laboratory experiments that underpin our current astrochemical knowledge, and pay particular attention to the many open questions that remain.
Course Notes: The course is offered every other year in the spring. ASTRON 115 is geared towards undergraduates, and 215 towards graduate students, respectively. Students who take 215 will receive additional weekly assignments, mainly engaging with the academic astrochemistry literature.
Prerequisites: Astronomy 16
## Astronomy 120: Stellar Physics
Instructor: Charles Alcock\
Offered: Fall 2025 (next offered Fall 2027)
Description: Stars are the basic building blocks of galaxies and are responsible for the nucleosynthesis of most of the elements. Topics include stellar structure; energy transport in stars; stellar atmospheres; astroseismology; nuclear fusion in stars; stellar evolution; nucleosynthesis of the elements; stellar death and supernovae; the degenerate remnants of stars; black holes. This course will make use of thermodynamics, statistical mechanics, and quantum mechanics, but will review these subjects as necessary.
Prerequisites: Astronomy 16
## Astronomy 130: Cosmology
Instructor: Xingang Chen\
Offered: Fall semesters
Description: The physical model describing the initial conditions, evolution, and ultimate fate of the Universe. Topics include cosmic dynamics; the Robertson-Walker Metric; curvature; estimating cosmological parameters; the accelerating universe; dark matter; gravitational lensing; the cosmic microwave background; nucleosynthesis; inflation and the very early universe; formation of structure. Note: Offered in alternate years.
Prerequisites: Astronomy 17, college-level Mechanics (e.g. Physics 15a) and Calculus (e.g. Math 1b)
## Astronomy 140: Introduction to General Relativity
Instructor: Xingang Chen\
Offered: Fall semesters
Description: Recent exploration of black holes, gravitational waves, and cosmology have revealed the relativistic Universe like never before. This course will introduce students to the theory of general relativity and some of its key applications. Topics include: review of special relativity, physics in curved spacetimes, the Einstein field equations, gravitational lensing, black holes, gravitational waves, and cosmology. Mathematics used in general relativity will be introduced along the way.
Prerequisites: Multivariable calculus (e.g. Math 21A), linear algebra and differential equations (e.g. Math 21B), college-level Mechanics including special relativity (e.g. Physics 15A), and E&M (e.g. Physics 15B)
## Astronomy 191: Astrophysics Laboratory
Instructor: John Kovac\
Offered: Spring semesters even years
Description: Laboratory and observational projects in astrophysics. Students design and undertake two projects from a selection including: observational studies of the cosmic microwave background radiation, molecules in interstellar clouds, the rotation of the galaxy, galactic molecular sources with the submillimeter array (SMA), stars and clusters with the Clay Telescope; and laboratory experiments including super-conducting submillimeter detectors, x-ray CCDs, and hard x-ray imaging detectors and telescopes.
Prerequisites: Astronomy 16, or Astronomy 17, or Physics 15C
## Independent Study
## ASTRON 91r Supervised Reading and Research
This is a course for supervised instruction of a individual student by an Astronomy faculty member. It is a letter-graded course (i.e., you can not take it Pass/Fail or Sat/Unsat). The Astronomy Director of Undergraduate Studies (DUS) is the instructor officially “offering” the course for registration purposes, but the course is supervised instruction of an individual student by an individual faculty member. (The "r" stands for "repeatable.")