Life in the Universe

January 9, 2018 | Author: Anonymous | Category: Science, Astronomy, Solar System
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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!

1st Imaged Exo-palnetary system !

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

First Day of the Class • Syllabus • contact info.

• Office Telephone Number: 706-542-7518 • E-Mail Address: [email protected]

Inseok Song Physics Building, Room 240

• Office Hours: Tue/Thu after the class or by an email appointment

Course Webpage: Check the course webpage frequently! or  “course websites”  ASTR1420

First Day of the Class • Syllabus • contact info. • course goals

• 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

Generally, class attendance will not be tracked. But, there will be significant(?) benefit for attending classes. ;-)

First Day of the Class • Syllabus • contact info. • course goals • textbook + exam

• Textbook: Life in the Universe, AddisonWesley, by Bennett & Shostak (2nd Ed. Or later) • Additional Reading: Occasional reading material (not in the textbook) will be posted in the course webpage. • Prerequisite: None

Final Score = best two in-class exams (80%) + lowest exam score (20%) + bonus credits (up to 10%)

• 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”.

First Day of the Class • Syllabus • contact info. • course goals • textbook + exam • grading • extra credits • make-up exam

• Grading: Final score will be scientifically rounded (i.e., 89.9  90 and 89.4  89). 90 ≤ A

87 ≤ B+ < 90 83 ≤ B < 87 80 ≤ B– < 83

77 ≤ C+ < 80 73 ≤ C < 77 70 ≤ C– < 73

60 ≤ D < 70

F < 60

• Extra credits: Occasional extra credit works

• 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. Term paper: • Single-spaced • ~5 pages

First Day of the Class • Syllabus • contact info. • course goals • textbook + exam • grading • extra credits • make-up exam • course goals • instruction method • withdrawal policy

• 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).

First Day of the Class • Syllabus • contact info. • course goals • textbook + exam • grading • extra credits • make-up exam • course goals • instruction method • withdrawal policy • Academic honesty • Code of conducts

• 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.

Synopsis of the Course


sections 1.1, 1.2, 1.4, 2.1, 2.3

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 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 1st 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? 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 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 •Astrobiology is …

• 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!

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 3rd 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 14th 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 nonscientific 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… You are being scientific in your daily life…

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.

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.

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, 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!


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

Important Terms

• Universality of Natural Laws

• Astrobiology

• Astrobiology as science

• Occum’s razor

• Scientific or non-scientific?

• Pseudo-science

Chapter/sections covered in this lecture : sections 1.1, 1.2, 1.4, 2.1, 2.3

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