|AST 309L · Search for Extraterrestrial Life
At one level, the subject of extraterrestrial life can be discussed in terms having to do with the physical and biological
sciences. For example, the question of which stars are most likely to have planets bearing life will involve discussions
of the origin of planetary systems, current searches for planets around other stars, and theories and evidence related
to the origin of life on earth. Whether or not you think creatures even remotely like us, or even like bacteria, will develop
elsewhere depends on your view of how particular forms of biological complexity developed during the history of the
Earth, whether that development was gradual and spontaneous, or triggered by external or catastrophic events, like
mass extinctions. The subject matter will gradually shift away from the physical sciences as we inquire into the development
of prebiological chemical evolution, biological evolution, "intelligence," language, cognition, and how they might differ
(or not exist, or be replaced by alternative concepts) in extraterrestrial life forms. Almost every question will involve an
impossible choice between what are usually called "convergence" and "contigency," which will be explained in class.
Most of the course will be devoted to two areas: 1. The formation and detection of extraterrestrial planets, and
2. Theories and experiments concerning the origin and earliest evolution of life here and elsewhere. That is most of the subject
of "astrobiology" or "exobiology." This subject has experienced a huge resurgence of scientific interest in the past decade due to
several factors that we will explore in detail. Astrobiology has finally become a legitimate field of science, with its own institutes,
funding programs, and even universities that offer advanced degrees in the subject. Other aspects of the problem, like "listening"
for signals or signs of extraterrestrial technological civilizations ("SETI" programs) and even potential designs for star travel vehicles
are also under study, so we will devote a significant fraction of time to these topics, but only at the end of the course.
The material will be almost entirely non-mathematical, concentrating on a number of key ideas that can be understood
without math, although they do require a solid conceptual grasp of the subjects, and a degree of comfort using graphs as an
important quantitative tool. You will be required to become familiar with a lot of elementary but diverse material from astronomy,
chemistry, and a bit of geology and cell biology. This material requires no background, nor gives any advantage to those who do
have some background--it is really at an elementary level. If you are not willing to study interdisciplinary material, please drop the
course now, but don't complain in the end that this wasn't a straight astronomy class! I suggest you immediately look through
your textbook to get a feel for the nature of the topics we will be covering. There is a fairly large vocabulary of terminology with
which you must become comfortable--I cannot overstress the importance of being able to speak about the topics covered in this
class coherently and comfortably. It is my repeated obsevation that students who have trouble on exams, even though they think
they studied diligently, are not comfortable with the terminology, and so are not really making sense of the exam questions;
conversely, the students who do well in this class are usually able to explain the material in words to someone unfamiliar with
the subject matter.
AST309L: SCHEDULE OF TOPICS, READINGS, AND EXAM DATES