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Life in the Universe

Life in the Universe. ASTR 1420 Tu/Th 12:30-1:45PM Room 221. by Inseok Song (“ iSong ”) Lecture #1. Are we alone in the Universe?. Ancient folks were wondering also…. Epicurus (341-270 B.C.) : atomists

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Life in the Universe

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  1. Life in the Universe ASTR 1420 Tu/Th 12:30-1:45PM Room 221 by Inseok Song (“iSong”) Lecture #1

  2. Are we alone in the Universe?

  3. Ancient folks were wondering also… • Epicurus (341-270 B.C.) : atomists There are infinite worlds both like and unlike this world of ours. … we must believe that in all worlds there are living creature and plants and other things we see in this world. • Aristotle (384-322 B.C.) : aristotelians The world must be unique... There cannot be several worlds • St. Thomas Aquinas (1225-1274): • integrated Aristotle’s philosophy into Christian theology.

  4. I am an exo-planet hunter! Co-Principal Investigator of Gemini Planet Imager Campaign Science team • Awarded 890hrs of 8m telescope time in Chile • 50 PhDs throughout the world. • 40+ million dollars project • starting late 2012 – 2015 • Will image dozens of Jupiters orbiting other stars The 1st Imaged Exo-palnetary system !

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

  6. First Day of the Class • Professor: Inseok Song • Office Number: Physics Building, Room 240 • Office Telephone Number: 706-542-7518 • E-Mail Address: song@uga.edu • Course Webpage: http://www.physast.uga.edu/iSong/ASTR1420 • Office Hours: 1hr after the class or by appointments (email preferred) • Syllabus contact info. • No Facebook… • Check the course webpage frequently! • http://www.physast.uga.edu “course schedule”  ASTR1420

  7. First Day of the Class • Course Goals: This course is not the one to memorize gory-details of “facts”. • Understanding the meaning of life in the Universe • Logics behind various searches for life • Scientifically understand the possibility of alien life forms in the Universe and put us in the grand context • Appreciating the precious nature of human beings is the most important goal • Syllabus contact info. course goals • Class attendance will not be tracked. • But, there will be significant(?) benefit for attending classes. ;-)

  8. First Day of the Class • Textbook: Life in the Universe, Addison-Wesley, by Bennett & Shostak (2nd Ed.) optional • Additional Reading: Lecture notes.. • Prerequisite: None • Exam: Three in-class exams, two best scores will be counted 40% each, and the worst score is to be counted 20%. Optional term paper for 5% credit. • Test questions will be a mixture of “multiple choices, “short answers”, and “essay”. • Syllabus contact info. course goals textbook + exam • Final Score • = best two in-class exams (80%) + worst exam (20%) + term paper (5%) + bonus credits (5-10%)

  9. First Day of the Class • Grading: Final score will be rounded (i.e., 89.9  90 and 89.4  89). • Extra credits: Occasional extra credit works • Term paper: A term paper counted as bonus points (up to 5%) toward the final score. Need to tell me about your incoming submission by March 1. • Make-up of missing exam: Need to send a notice to me before the exam. Or, with a legitimate excuse, you can tell me afterward. Then, I will arrange a make-up test. • Syllabus contact info. course goals textbook + exam grading extra credits make-up exam • Term paper: • Single-spaced • a separate title page. • no more than 5 pages

  10. 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. • Classroom code of Conducts: Follow general rules and use your common sense. • Syllabus contact info. course goals textbook + exam grading extra credits make-up exam course goals instruction method withdrawal policy Academic honesty Code of conducts

  11. Synopsis of the Course

  12. Astrobiology Science vs. non-Science sections 1.1, 1.2, 1.4, 2.1, 2.3

  13. Is it reasonable to imagine life beyond Earth? • 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? If we find nearly identical planets to Earth, then, could similar biological processes of Earth have happened on those planets? • Vast Universe! At least to the 1st part of the question (“if we find identical planets”), yes we started finding such planet(s) already (Kepler 22b).

  14. Vast Universe!

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

  16. Vast Universe : Hubble Ultra Deep Field In the Universe, there are about 10 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…

  17. Astrobiology • What is astrobiology? scientific study of life in the Universe : (= bioastronomy = exobiology) ; any kind of conceivable life forms! It spans biology, chemistry, geology, physics, paleontology, planetary science, religion, philosophy, and astronomy. • Three major areas of astrobiology • Astronomy : provide context to the search. “If something happened here on Earth, the same thing might have happened somewhere else.” • Planetary science : understand planets; frequency, formation & evolution. Habitability of planets! • Biology : universality of biology? Life on Earth arose quite early in Earth’s history!

  18. Astrobiology • More than 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 …

  19. Astrobiology as a science (not pseudo-science) What is Science ? Characteristics of Science • Seek explanations for observations • Create/test models to explain observations • Testable predictions observations  verifiable by a 3rd person. models  should be as simple as possible. Occum’s razor

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

  21. Pseudo-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.

  22. Scientific… Say that you are looking for a used car, and you are offered a lovely, 1-year old Porsche for just $3,000. ?Why should the price 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 being scientific : skeptical and looking for greater confidence in a drawing conclusion. You are being scientific in your daily life…

  23. Tentativeness : Being “Scientific” is not absolute! • 200 years ago, French Academy of Science declared that the notion of stones falling from the sky (e.g., meteorites) by Chladniis not scientific; a complete nonsense. • why? Scientific evidence for this hypothesis (claim) is lacking… • Then, the claim by Ernst Chladni received a spectacular confirmation by a prominent metro shower near L’Aigle, France in 1803.

  24. 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, 2020. • 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! Does not matter if it is right or wrong!

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

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