Science 3211: Search For Life in the Universe

Transcription

1 Science 3211: Search For Life in the Universe Friday 1 pm 4 pm, MI 920 Jonathan Dursi Overview A decade ago, scientists who spent time thinking about life elsewhere in the universe were considered somewhere between eccentric and crackpots not because the idea was outlandish, but because there seemed to be nothing for a scientist to do but speculate wildly on the topic. Today, over a hundred planets outside our solar system are known; and even as they continue to be detected, new and more powerful techniques for their discovery are being developed. At the same time, our knowledge of planetary science and elementary biology is growing by leaps and bounds. It is becoming more and more reasonable to carefully examine the question of whether any of those other planets could be inhabited. Astrobiology is becoming a respectable discipline, and Caltech students can even major in it. This course will cover the Astronomy, Geoscience, and Biology that underlies the current search, and take a look at how the search is being performed, both directly in our Solar System, and by observations of stars far distant. Goals of the Course My intent is that a student who passes this course will: Understand how science is applied to such an open-ended question. Learn several fundamental concepts of astronomy, geosciences, and biology, and understand the roles they play in the development of life here and elsewhere. Be able to distinguish between real science (SETI, planet detection, microbiology, NASA s Origins project) and pseudo-science (Alien Autopsies, Abduction Insurance, crop circles) on the subject. Have learned enough of the basic science that they are able to keep up with new developments in the field. Textbook Readings and questions will be assigned from The Search for Life in the Universe, Goldsmith & Owen, Third Edition. Earlier editions might well be ok, but you re responsible for making sure the content and questions are the same. 1

2 Search for Life in the Universe 2 Marking Credits will be awarded for assignments, quizes, and a final project or presentation. Full credits will be given for fully correct or complete work. Half-credits will be given if the answer is not fully correct or complete, but the student has convinced me that they fully understand the material. No credits otherwise. At the end of the course, a pass mark will be given if a student has gotten slightly more than half of the credits available (that is, on average they understand all the material); a fail mark will be given otherwise. There will be bonus credits for bringing clippings of news or current events material from the past week relevant to the class, and for other class participation activities as they arise. There will be one assignment (worth two credits) and one short quiz on the readings (worth one credit) per week. The two bigger assignments on March 12 and May 7 will be worth four credits. A final project or presentation will be worth ten credits. Lecture Structure Most class sessions will go something like this: 1:00 Reading Quiz on the material to be covered today 1:10 Discussion of questions from last week, and of materials brought in by students today. 1:25 Overview of concepts for this week 1:40 Lecture 1 : 2 or minute lectures, each followed by class discussion/problem solving 2:35 Well-deserved break 2:50 Lecture 2 : 2 or minute lectures, each followed by class discussion/problem solving 3:45 Hand out assignment on this material and readings for next week, and the weekend begins Contacting the Instructor Messages for me can be left in my mailbox; you ll probably get a quicker response by , which I check at least daily (jdursi@artic.edu). I ll take questions about course material by private , but I d prefer that you (also?) post it to the course blog so that we can all discuss the answer together. Attendance We ll be going through a lot of material, so showing up prepared both teacher and students is important. I ll do roll call attendance the first couple of classes to make sure I know students names. Students who miss more than two reading quizzes will have to meet with me.

3 Search for Life in the Universe 3 Course Outline This outline is (of course) subject to change depending on the progress we make through the semester. I expect that we will cover all of the chapters in the textbook, although there will be some material in many chapters that we will likely skip. Chapters for assigned readings are given; in class (and on the blog) I will specify which sections of each chapter can be omitted. Jan 30 Feb 6 Feb 13 Questionnaire Lecture 1: Search (How does science search for knowledge?) What is Science? How do Scientists know things? What are the alternatives? Discussion of the questionnaire Lecture 2: Life (What are we searching for, and how will we know it?) What do we mean by life? What can t be alive? What sort of life are we looking for? Readings: Skim chapters 1 (the search), 7 (Life on Earth), 10 (Limits of Life); Read chapters 2 (the Universe), 18 (Drake Equation). Assignment 1, on Chapters 1,7, & 10. Reading Quiz (Chapters 2 & 18) Lecture 3: The Universe What is the Universe Made Of Structure in the Universe: Clusters, Galaxies, Stars Measuring Distances The Distance Scale Lecture 4: Life in the Universe The Drake Equation Readings: Chapter 6 (galaxies) and handout. Assignment 2, on Chapters 2 & 18. Reading Quiz Lecture 5: Tools for looking at our Universe Electromagnetic radiation Spectra Inverse Square Law Lecture 6: Galaxies

4 Search for Life in the Universe 4 Feb 20 Feb 27 Mar 5 Readings: Chapter 3,4,5 (stars). Assignment 3, on Chapter 6 and handout. Reading Quiz: Chapter 3, 4, 5. Questionnaire II Lecture 7: Stars Birth Evolution Death, and birth of new stars Lecture 8: Planets and Solar Systems Formation of Planets in Solar System Evolution of Planets Readings: Chapter 8 (Origin of Life). Assignment 4, on Chapters 3,4,&5 Reading Quiz, Chapter 8 Lecture 9: Origin of Life I Getting an atmosphere Evolution of the Atmosphere History of thought of the origin of life Lecture 10: Origin of Life II Chemical Evolution Model Testing the Model Alternatives Readings: Chapter 9 (Evolution of Life). Assignment 5, on Chapter 8 Reading Quiz, Chapter 9 Lecture 11: Evolution of Life I Uni-cellular and multicellular life Increasingly complex life What is necessary for these organisms Lecture 12: Evolution of Life II Suitable Stars Suitable Planets Intelligence Assignment 6 on Chapter 9

5 Search for Life in the Universe 5 Mar 12 Mar 19 Lecture 13: Student Presentations Lecture 14: Review: How life (may have) come to be Galaxies, Stars, Planets, Life The Drake Equation Readings: Chapters 11 & 12. (Big) assignment 7 on Parts 2 & 3, and student presentations. Reading Quiz, Chapter 11 & 12 Lecture 15: A Brief History of the Solar System The picture Evidence from comets, dust Complex organics in the solar system Lecture 16: Venus and the Greenhouse Effect Measurements and Explorations of Venus Why Venus is so different Life on Venus? Readings: Chapters 13 & 14. Assignment 8 on Chapters 11 & 12. Mar 26 Spring Break Apr 2 Questions from last class, and discussion of related materials Reading Quiz, Chapters 13 & 14 Lecture 17: Mars Observations and Explorations of Mars Viking Spirit, Opportunity Lecture 18: The Search for Life on Mars What does an alien microorganism look like? Analysis of early experiments Consequences of those results Readings: Chapters 15 & 16. Assignment 9 on Chapters 13 & 14. Apr 9 Critique Week Apr 16

6 Search for Life in the Universe 6 Apr 23 Apr 30 May 7 May 14 Reading Quiz on Chapters 15 & 16 Lecture 19: The Giants and their moons Explorations of outer solar system What the gas giants are made of Could life exist there? Lecture 20: How Unique is Earth? What makes Earth so lively? Accidentally staying alive The search for other planets Readings: Chapter 17. Assignment 10 on Chapters 15 & 16. Reading Quiz, Chapter 17 Lecture 21: Extrasolar Planets I How do we know Techniques Results Lecture 22: Extrasolar Planets II Looking closer at the planets Atmospheres? NASA PlanetQuest Readings: Chapter 19, 20. Assignment 11 on Chapters 17. Reading Quiz, Chapter 19, 20 Lecture 23: Interstellar Travel Lecture 24: Interstellar Communications Reading Quiz, Chapter 21, 22 Lecture 25: UFOs? Lecture 26: Are We Alone? Readings: Chapter 21, 22. (Big) assignment (13!) on Parts 4 & 5. Lecture 27: Student Presentations Lecture 28: Conclusion

7 Search for Life in the Universe 7 Web Resources The course website will be at ljdursi/seti/. I will keep current course materials available there. Linked from that page will be the course blog; I ll post announcements and news there. It s also the best place to ask questions about the course; you are welcome to me questions privately, but if you post your questions on the blog, we can all discuss the answers together. The Origins theme of NASA research is described at This theme of research asks the question of how life originated here, and how it might have originated elsewhere. There s a wealth of information here. The NASA PlanetQuest website ( contains detailed information and current news on the search for planets, and especially Earth-like planets. Astrobiology Magazine, at is a great web-based news site on Astrobiology. Another similar site is which is aimed more at working scientists. The SETI (Search for ExtraTerrestrial Intelligence) web page is Thinkquest has an Astrobiology web page that contains some good introductory information at The debate on whether there is evidence for past life on Mars is described in some course materials at Dartmouth ( humbio01/desc.html). Another good web source for information about the search for life in the solar system in general is available at intro.htm. For general astronomy, is the Astronomy Picture of the Day, and is always a good place to go for stunning pictures and nice explanations. Light Years, and great explanations for some other Astronomy jargon, is described at the Electronic Sky ( For descriptions of really bad Astronomy in the movies or on TV, the Bad Astronomy website is indispensable ( is a really good set of pages for introductory biology information.