Astrophysics Freshman Seminars 2019-20



Charles R. Alcock (Department of Astronomy) Freshman Seminar 23R 4 credits (fall term) Enrollment: Limited to 12 Note: The seminar will make use of the Clay Telescope on the roof of the Science Center. There may also be a trip to the Observatory at 60 Garden Street to visit the Great Refractor.

Comets have been seen regularly since before the beginning of recorded history. They have often been regarded as disturbing portents. Asteroids, on the other hand, were not discovered until the 19th century, with the advent of astronomy with telescopes. Today we know of many more asteroids than comets, but we believe that there are vastly more comets than asteroids in the solar system. This seminar will start with the history of the study of comets and asteroids, including the “Great March Comet of 1843,” observations of which led to the establishment of the Harvard College Observatory and its Great Refractor, at the time the largest telescope in the Americas. Our understanding of comets advanced dramatically in 1950 with the publication of two extraordinary papers: Whipple (then at Harvard) described the mixture of dust and ice that comprises the nuclei of comets, and Oort (Leiden University) showed that new comets enter the inner solar system from a vast, diffuse cloud surrounding the planetary system. Modern telescopes and spacecraft encounters provide us today with a wealth of information about comets and asteroids. We will examine these observations and learn what is known and what is inferred about the origin and structure of asteroids and comets. The students will observe with the Astronomy Laboratory’s Clay Telescope on the roof of the Science Center. Students will take on projects, which may involve their own observing program, or which exploit existing data.


Andrew Strominger (Department of Physics) Freshman Seminar 21V 4 credits (fall term) Enrollment: Limited to 12

The quest to understand the fundamental laws of nature has been ongoing for centuries. This seminar will assess the current status of this quest. In the first five weeks, we will cover the basic pillars of our understanding: Einstein’s theory of general relativity, quantum mechanics and the Standard Model of particle physics. We will then examine the inadequacies and inconsistencies in our current picture, including, for example, the problem of quantum gravity, the lack of a unified theory of forces, Dirac’s large numbers problem, the cosmological constant problem, Hawking’s black hole information paradox, and the absence of a theory for the origin of the universe. Attempts to address these issues and move beyond our current understanding involve a network of intertwined investigations in string theory, M theory, inflation and non-abelian gauge theories and have drawn inspiration from the study of black holes and developments in modern mathematics. These forays beyond the edge of our current knowledge will be reviewed and assessed. The format of the course will be discussion of weekly reading assignments and a final paper. Non-scientists are welcome. COSMIC EXPLOSIONS Edo Berger (Department of Astronomy) Freshman Seminar 21C 4 credits (spring term) Enrollment: Limited to 12 Somewhere in the universe a massive star ends its life in a supernova explosion every second (you can count: “1 supernova, 2 supernova, 3 supernova…”). These supernovae, and other types of cosmic explosions like them, play a critical role in shaping the universe. They are responsible for the synthesis and dispersal of all the chemical elements heavier than hydrogen and helium, and, therefore, provide the building blocks for the next generations of stars, for planets and ultimately for life. These cosmic explosions also give birth to exotic objects, such as neutron stars and black holes. Finally, the explosions are so powerful that they can influence the formation of new stars within their galaxies. In this seminar, we will explore how different types of cosmic explosions occur and how they influence the universe and life within it. Equally important, we will actually use telescopes in Cambridge and in Arizona to study a new supernova explosion during the semester.


Abraham Loeb (Department of Astronomy) Freshman Seminar 21G 4 credits (spring term) Enrollment: Limited to 12
Since the universe is expanding, it must have been denser in the past. But even before we get all the way back to the Big Bang, there must have been a time when stars like our sun or galaxies like our own Milky Way did not exist, because the universe was denser than they are. We, therefore, face the important question about our origins: How and when did the first stars and galaxies form? Primitive versions of this question were considered by humans in religious and philosophical texts for thousands of years, long before it was realized that the universe expands. The Seminar will summarize the fundamental principles and scientific ideas that are being used to address this question in modern cosmology. Previous generations of scholars have also wondered about the long-term future of the universe. For the first time in history, we now have a standard cosmological model that agrees with a large body of data about the past history of the universe. The seminar will conclude with the forecast that this scientific model makes about our future. It will be based on a book with the same title written by Professor Loeb (Princeton University Press, 2010). PHYSICS AND BIG QUESTIONS Gerald Gabrielse (Department of Physics) Freshman Seminar 22V 4 credits (spring term) Enrollment: Limited to 12 Three types of big questions will be considered. The first are the big questions about the limits and domain of physics. To start, what are the limits and domain of applicability of the classical physics studies studied in high school? How do these relate to special relativity, quantum mechanics and quantum field theory? Next, what are some of the big questions that physics seeks to answer. For example, what is the “standard model” of particle physics, and how is it tested? Other important big questions relate to how physics informs some major challenges to our society. For example, what does physics say about the options for powering our homes and cars, given limited petroleum reserves and the need to reduce carbon dioxide production? The final set of big questions is about the compatibility or incompatibility of physics and religious faith. Here we will consider very divergent answers in a climate of respect for what will be big differences in opinion.


Karin Öberg (Department of Astronomy) Freshman Seminar 50S 4 credits (fall term) Enrollment: Limited to 12
Prerequisites: The seminar will include scientific concepts and their empirical and theoretical
foundations, but no scientific preparation beyond high school physics is required.

It is easy to find controversies at the intersection of science and religion, from the time of Galileo, to
Darwin and the emergence of modern cosmology. Yet many scientists throughout the ages have been
devoutly religious, challenging claims of an intrinsic enmity between science and religion. This seminar treats a number of historical conflicts between religious beliefs and scientific theories, among
them the Galileo affair, the clockwork universe, evolution, and the Big Bang theory. The seminar
will introduce students to the main protagonists through their own words, and through contemporary and modern-day commentaries. We will explore why these conflicts arose and, based on these
historical lessons, what we can expect the future relationship between science and religion to be.
The ultimate aim of this seminar is for students to form their own opinion of which kind of conflicts
between science and religion are inevitable and which are accidents of time and place, and under
which conditions, if any, interactions between science and religion can be mutually beneficial. Most
of the seminar will focus on Christianity and the natural sciences, with emphasis on astronomy and
cosmology, but the relationship between other ancient and contemporary religions and other sciences
will be discussed as well to provide a broader context.


Jonathan E. Grindlay (Department of Astronomy) Freshman Seminar 50I 4 credits (spring term) Enrollment: Limited to 12 Note: This seminar is open to all but may be of particular interest to those considering physical science or engineering concentrations.
The universe is not static, but rather stars and entire galaxies are evolving as revealed by their variability on timescales ranging from giga-years for galaxies to milliseconds for collapsed stars (neutron stars and black holes). In this seminar, we shall explore stars and galaxies through variability—from how brightness variability of stars with binary companions measured with small telescopes measures star masses and radii, to the extremes of variability of stars that undergo repeated huge flares, to enormously luminous variations from accretion onto gargantuan black holes in the nuclei of “Active Galaxies” (Blazars and Quasars). We shall use the Clay Telescope on the Science Center roof to make some repeated observations (from the 8th floor Astronomy Lab) of an example of each of these two types of variable stars and deduce what life would be like if either were our sun. From a Blazar, we shall observe historical outbursts that occasionally change brightness to exceed its host galaxy by a factor of ~100, by using the digitized brightness measures of this object on thousands of glass-plate images taken by Harvard telescopes from 1885 to 1992 and now digitized and online from our Digital Access to a Sky Century @ Harvard (DASCH) project. The seminar will include readings from an introductory astronomy text, as well as both popular and journal articles and the short book Black Hole (Bartusiak). Students will use astronomical software to measure stellar brightness and variability from telescope images, as well as learn temporal analysis techniques with applications to other disciplines. Students discuss in class readings and observations conducted and write short papers on their observations and deductions.


Lisa Randall (Department of Physics)  Freshman Seminar 26J 4 credits (spring term) Enrollment: Limited to 12
This seminar will give an overview and introduction to modern physics. As with the book, Warped Passages, on which it will be loosely based, the seminar will first consider the revolutionary developments of the early twentieth century: quantum mechanics and general relativity; and then it will investigate the key concepts which separated these developments from the physical theories which previously existed. We will then delve into modern particle physics and how theory and experiment culminated in the “Standard Model of particle physics,” which physicists use today. Then we will move beyond the Standard Model into more speculative arenas, including supersymmetry, string theory, and theories of extra dimensions of space. We will consider the motivations underlying these theories, their current status, and how we might hope to test some of the underlying ideas in the near future.



Peter Koellner (Department of Philosophy) & W. Hugh Woodin (Department of Mathematics and of Philosophy)
Freshman Seminar 23C 4 credits (spring term) Enrollment: Limited to 12

Infinity captivates the imagination. A child stands between two mirrors and sees herself reflected over and over again, smaller and smaller, trailing off to infinity. Does it go on forever? … Does anything go on forever? Does life go on forever? Does time go on forever? Does the universe go on forever? Is there anything that we can be certain goes on forever? ... It would seem that the counting numbers go on forever, since given any number on can always add one. But is that the
extent of forever? Or are there numbers that go beyond that? Are there higher and higher levels of infinity? And, if so, does the totality of all of these levels of infinity itself constitute the highest, most ultimate, level of infinity, the absolutely infinite? In this seminar we will focus on the mathematical infinite. We will start with the so-called “paradoxes of the infinite,” paradoxes that have led some to the conclusion that the concept of infinity is incoherent. We will see, however,
that what these paradoxes ultimately show is that the infinite is just quite different than the finite and that by being very careful we can sharpen the concept of infinity so that these paradoxes are transformed into surprising discoveries. We will follow the historical development, starting with the work of Cantor at the end of the nineteenth century, and proceeding up to the present. The study of the infinite has blossomed into a beautiful branch of mathematics. We will get a glimpse of this subject, and the many levels of infinity, and we will see that the infinite is even more magnificent than one might ever have imagined.