UW News

December 3, 2009

Class Notes: Astrobiology studies the nature of life — starting with Earth

Class title: Astrobiology 115: Life in the Universe. Taught by Woody Sullivan III, professor of astronomy, with teaching assistant Jeff Bowman.

Description: The class syllabus states, “Astrobiology is an exciting new scientific field that examines the nature of life as we know it on planet Earth, and then considers where and how to search for life elsewhere. It asks some of the most basic questions: What is the nature of life? How did life begin on Earth? How has it changed over billions of years? Where can life survive on Earth? Is there life on other planets? What conditions should those planets have? How can we search for extraterrestrial life? Is there intelligent extraterrestrial life?

“Astrobiology is highly multidisciplinary, with contributions from astronomy, biology, geology, biochemistry, atmospheric sciences, oceanography, and many other fields.”

Under the heading “Course philosophy,” the syllabus tells students the goal is not to turn them into scientists. “Rather, we hope to infect you with some of our enthusiasm and excitement for a subject which has fascinated humans for a long time. We hope that by the end of the quarter you will have a better appreciation for our perception of our place in the universe and how that in turn affects our view of ourselves. We will also use astrobiology as a vehicle by which to give you insight into the workings of science, an amazing method of knowing the world that has been extremely influential over the past four centuries.”

Astrobiology is a five-credit class currently taught once a year that meets Mondays, Wednesdays and Fridays with Sullivan and Tuesdays and Thursdays with Bowman. The class is not intended for upper-division majors in science, engineering or other technical fields.

Instructor’s views: “This is the only scientific area of study that has yet to prove that its subject matter exists,” Sullivan said with a smile. He added, “There’s no doubt that you have to be somewhat optimistic if you’re going to be in this field at all.”

But astrobiology isn’t just waiting for life to be discovered in space, Sullivan said. “It’s broader than that. It’s studying the life on the planet that we do know about — its origin and history — and the properties and history of the 400 planets we have (discovered) going around other stars. … And then applying this knowledge to the question of where should we look for life in our solar own system?”

Astrobiology, Sullivan said, also explores the possibilities of “life as we do not know it.” It seems narrow to search only for life that meets Earth criteria, “but how much do you broaden out? The more you broaden out the less powerful your instrument’s going to be.” Extraterrestrial life may not be based on water and carbon, “but that’s a good place to start,” he said.

Asked what the class offers the average student, Sullivan said, “I’d say it gives you a cosmic perspective about the nature of life.”

Sullivan said it will likely be a long time before we can actually search for life in a sample gathered from another planet, but studying the spectrum of planets’ atmospheres could help determine whether they hold the possibility of life. He said within a few years more will be known about “exoplanets” — those outside our solar system — “and I think that’s going to engage the public in a way that hasn’t happened before.”

He said astrobiology speaks to the fundamental question, “Am I alone? Who am I, and what is my place? For the first time we can do some scientific investigation rather than just speculating.”

Unexpected experiences: Sullivan said it’s not exactly unexpected, but when the class takes up discussions of the origins of life and searching for it beyond Earth, “you get into some fundamental philosophical and religious questions. Students will ask about how various religions might be affected by the discovery of extraterrestrial life, or raise ethical concerns over how we are contaminating Mars with our own microbes.”

He deals with many religious questions by exploring with students the difference between science and religion. Science, he said, “gives prizes to those that upset the apple cart, and so that’s a very different enterprise than preserving a belief.”

Student views: Student Chris Di Re, an astronomy major turned history major, said the course is an interesting elective for him. “The class deals with the life long quest of finding life in the universe; something I have always been intrigued about.” He added, “I really like science, so I find the most interesting part of the class is learning how we search for life and why we use what we use to do that.” He said because our technology doesn’t allow us to visit most planets directly, “we have to use a number of methods, such as spectroscopy, to determine what it is made of and if it may be habitable.”

Di Re said Sullivan “is an incredible professor and is always excited to teach our class. You can tell he genuinely enjoys it by the way he speeds up his lecture every time the class is in the final few minutes because he’s trying to get every last bit of detail out on whatever he is lecturing about.” Di Re also had kind words for the teaching assistant, Jeff Bowman, who he said “knows the subject very well and is very personable so it’s easy to ask him questions and to talk to him.”

Student Jordan Swarthout said he’s taking the class to satisfy a natural world credit. The class is both challenging and interesting, he said. “Professor Sullivan does a great job of both breaking down complex science into an accessible form for liberal arts majors while leaving room for those particularly ensnared by his passion for the subject to delve into as deep a level as they feel comfortable,” Swarthout wrote in an e-mail.

Assignments: There are weekly readings and students are required to write and file reports on classroom experiments and other activities. Grades are based on four midterm quizzes, homework and activities, evaluations by the teaching assistant and a final exam.

Reading: Life in the Universe, by J. Bennett and S. Shostak, second edition, 2007.

Class Notes is an occasional column that describes interesting or unusual classes at the UW.