Life in the Universe ASTR 1420 Tu/Th 12:30-1:45, Room 221 by Inseok Song Lecture #1

I am an exo-planet hunter! 1 st Imaged Exo-palnetary system !

… trying to understand the origin of planetary systems In Pleiades, a collision between two planets! In Pleiades, a collision between two planets!

First Day of the Class Office Telephone Number: Office Telephone Number: Address: Address: Office Hours: Tue/Thu after the class or by an appointment Office Hours: Tue/Thu after the class or by an appointment Syllabus Syllabus contact info. Inseok Song Physics Building, Room or  “course websites”  ASTR Check the course webpage frequently! Course Webpage: Check the course webpage frequently!

First Day of the Class Course Goals: This course is not the one to simply memorize gory details. Course Goals: This course is not the one to simply memorize gory details. 1.Understanding the meaning of life in the Universe 2.Scientifically understand the possibility of alien life forms in the Universe and put us in the grand context 3.Appreciating the precious nature of human beings are the most important goal Syllabus Syllabus contact info. course goals Generally, class attendance will not be tracked. But, there will be significant(?) benefit for attending classes. ;-)

First Day of the Class Textbook: Life in the Universe, Addison- Wesley, by Bennett & Shostak (2 nd Ed. Or later) Textbook: Life in the Universe, Addison- Wesley, by Bennett & Shostak (2 nd Ed. Or later) Additional Reading: Occasional reading material (not in the textbook) will be posted in the course webpage. Additional Reading: Occasional reading material (not in the textbook) will be posted in the course webpage. Prerequisite: None Prerequisite: None Exam: Three in-class exams, two best ones (40% + 40%) and the lowest one (20%). Occasional optional homework for bonus credit (up to 10%). Questions will be a mixture of “multiple choices, “short answers”, and “essay”. Exam: Three in-class exams, two best ones (40% + 40%) and the lowest one (20%). Occasional optional homework for bonus credit (up to 10%). Questions will be a mixture of “multiple choices, “short answers”, and “essay”. Syllabus Syllabus contact info. course goals textbook + exam Final Score = best two in-class exams (80%) + lowest exam score (20%) + bonus credits (up to 10%)

First Day of the Class Grading: Final score will be scientifically rounded (i.e., 89.9  90 and 89.4  89). Grading: Final score will be scientifically rounded (i.e., 89.9  90 and 89.4  89). Extra credits: Occasional extra credit works Extra credits: Occasional extra credit works Term paper: A term paper counted as bonus points (up to 5%) toward the final score. Term paper: A term paper counted as bonus points (up to 5%) toward the final score. Make-up of missing exam: With a legitimate excuse, student may submit an essay paper (about 10 pages) on a subject from the list of term paper topics. Make-up of missing exam: With a legitimate excuse, student may submit an essay paper (about 10 pages) on a subject from the list of term paper topics. Syllabus Syllabus contact info. course goals textbook + exam grading extra credits make-up exam Term paper: Single-spaced Single-spaced ~5 pages ~5 pages 87 ≤ B+ < ≤ C+ < ≤ D < 70 F < ≤ A83 ≤ B < 8773 ≤ C < ≤ B– < 8370 ≤ C– < 73

First Day of the Class Method of Instruction: During class periods, lectures will be given mostly via powerpoint presentation and all lecture notes will be accessible from the course webpage. Method of Instruction: During class periods, lectures will be given mostly via powerpoint presentation and all lecture notes will be accessible from the course webpage. Withdrawal Policy: Know the rules concerning withdrawals and incompletes, published in the UGA Undergraduate Bulletin. Note that I will NOT withdraw you from the course for excessive absences. Note also that after the midpoint of the semester, a withdrawal is assigned a grade of WF, except in those cases in which the student is doing satisfactory work and a withdrawal is recommended by the Office of Student Affairs (because of emergency or health reasons). Withdrawal Policy: Know the rules concerning withdrawals and incompletes, published in the UGA Undergraduate Bulletin. Note that I will NOT withdraw you from the course for excessive absences. Note also that after the midpoint of the semester, a withdrawal is assigned a grade of WF, except in those cases in which the student is doing satisfactory work and a withdrawal is recommended by the Office of Student Affairs (because of emergency or health reasons). Syllabus Syllabus contact info. course goals textbook + exam grading extra credits make-up exam course goals instruction method withdrawal policy

First Day of the Class Academic honesty: If you are using someone else’s work in your report, you need to clearly provide the reference (even if it is a simple URL). Otherwise, your work will be regarded as plagiarism and a serious case will be reported to the University. Academic honesty: If you are using someone else’s work in your report, you need to clearly provide the reference (even if it is a simple URL). Otherwise, your work will be regarded as plagiarism and a serious case will be reported to the University. Classroom code of Conducts: Follow general rules and use your common sense. Classroom code of Conducts: Follow general rules and use your common sense. Syllabus Syllabus contact info. course goals textbook + exam grading extra credits make-up exam course goals instruction method withdrawal policy Academic honesty Code of conducts

Synopsis of the Course

ASTROBIOLOGY SCIENCE VS. NON-SCIENCE sections 1.1, 1.2, 1.4, 2.1, 2.3

Is it reasonable to imagine life beyond Earth? Universality of Physics and Chemistry Universality of Physics and Chemistry Observed data show that same laws of nature govern our Earth, Solar System, Galaxy as well as galaxies far far away. Similarly, distant stars/galaxies are made from the same chemical elements as ours. Can biology also be universal? Can biology also be universal? If we find a nearly identical planet to Earth, then could a similar biological process happened on Earth take place on this planet? o Vast Universe! One step at a time: We can make a significant advance in the 1 st part of the question (“if we find identical planets”) already! We should be able to find such planet(s) in near future.

Vast Universe Hubble Ultra Deep Field: in a very small region of the sky (similar to the angular extent of a penny placed at the end of a football field), ~10,000 galaxies were found.

Vast Universe : Hubble Ultra Deep Field In the Universe, there are about 100 billions galaxies! And, each galaxy has about the same number of stars as in the Milky Way  So, there have to be Earth-like planets somewhere out there…

Astrobiology What is astrobiology? What is astrobiology? scientific study of life in the Universe : (= bioastronomy = exobiology) Currently, it does not include all kinds of conceivable life forms! It spans biology, chemistry, geology, physics, paleontology, planetary science, religion, philosophy, and astronomy. Three major areas of astrobiology Three major areas of astrobiology o Astronomy : provide context to the search. “If something happened here on Earth, the same thing might have happened somewhere else.” o Planetary science : understand planets; frequency, formation & evolution.  Habitability of planets! o Biology : universality of biology?

Astrobiology More than a simple search for extraterrestrial life or intelligence. More than a simple search for extraterrestrial life or intelligence.  Connection between life and environment  Therefore, even the “null result” of the search for life is significant as finding life! Astrobiology is … Astrobiology is …

Search for Life as a science What is Science ? Characteristics of Science 1.Seek explanations for observations 2.Create/test models to explain observations 3.Testable predictions scientific observations  should be verifiable by a 3 rd person. counter-example: UFO sightings models  should be as simple as possible.  Occum’s razor

Occum’s Razor lex parsimoniae = Law of Parsimony = Law of Succinctness 14 th century English Franciscan Theologian, William Ockahm “entities must not be multiplied beyond necessity” “Occum’s razor” = a true explanation of a given phenomenon should make as few assumptions as possible. All science models should be in the simplest form!

Pseudo-Science (“false” science) Pseudo-science : handling the nature appearing as a true science, but it involves a non- scientific handling of evidence or method. (Ex) Biorythm: every human being has three distinct cycles (physical: 23 days, emotional: 28 days, intellectual: 33 days) which determine the fate of an individual.

Pseudo-Science Astrology : a relationship between astronomical phenomena and events in the human world.

Scientific… Say that you are looking for a used car, and you are offered a lovely, 1-year old Porsche for just $3,000. Say that you are looking for a used car, and you are offered a lovely, 1-year old Porsche for just $3,000. It’s quite natural for you to wonder… ?Why should the price be so low? ?Does the car run? ?Has it been wrecked and poorly rebuilt?  Ask your friend  Take a test drive  Get examined by a mechanic you trust  Or all of the above being scientific : skeptical and looking for greater confidence in drawing a conclusion. You are being scientific in your daily life… $3,000

Being “Scientific” is relative! 200 years ago, French Academy of Science declared that the notion of stones falling from the sky (e.g., meteorites) by Chladni is not scientific; a complete nonsense. 200 years ago, French Academy of Science declared that the notion of stones falling from the sky (e.g., meteorites) by Chladni is not scientific; a complete nonsense.  why? Scientific evidence for this hypothesis (claim) is lacking and there is no way to confirm it or deny.  Then, the claim by Ernst Chladni received a spectacular confirmation by a prominent meteor shower near L’Aigle, France in 1803.

Scientific or not? ?UGA has the best college football team in the nation. ?Several miles below its surface, Europa (one of Galilean moons) has an ocean of liquid water. ?Terrestrial bacteria can survive on Mars. ?A huge fleet of alien ships will land on Earth and introduce an era of peace and prosperity on January 1, ?There is no liquid water on the surface of Venus today. ?My house is haunted by ghosts, who makes the creaking noises I hear each night. ?God created the Universe with all Laws of Nature (e.g., Law of Motion, evolution, etc) Logic and clarity are the most important!

Astrobiolgy Astrobiology is the scientific study of life in the Universe! The origin, evolution, distribution, and future of life in the Universe Verifiable!!

In summary… Important Concepts Universality of Natural Laws Astrobiology as science Scientific or non-scientific? Important Terms Astrobiology Occum’s razor Pseudo-science Chapter/sections covered in this lecture : sections 1.1, 1.2, 1.4, 2.1, 2.3