Honors 228 Astrobiology Prof. Geller Meeting #2 - Physical Origins Presented 27 January 2005

Overview of Chapter 1 1.1 Life “Elsewhere” Some discussion in 1st meeting 1.2 Worlds Beyond Imagination distances between worlds distances between stars communications between star systems 1.3 Stuff of Life birth and death of stars and planets origin of the chemical elements chemistry review formation of solar system other solar systems

Another Word about Astrobiology 1.5 The new science of astrobiology How new is it? What is new about it? Astrobiology according to Geller ODDS origins development distribution search

Discussion Questions Question #1: A) Can life exist in places that never receive sunlight? If Yes » What types of life forms could exist? If No » Cite the physical reasons why life cannot exist without sunlight. B) What elements are the most important for the existence of life? Explain your reasoning.

Discussion Questions Question #2: A) Consider the following statement: "For a life form to exist, liquid water must be present in the local environment in at least small amounts or for short time periods." Do you agree or disagree with this statement. If You Agree » Explain why liquid water is necessary. If You Disagree » What type of life could exist and what would the environment be like? B) We know that there are 9 planets orbiting the Sun in our solar system. Would you expect there to be other planets orbiting other stars outside our solar system? Explain why or why not.

Discussion Questions Question #3: A) Can any forms of life exist in environments with temperatures much greater than 100°C (the boiling point of water) or much less than 0°C (the freezing point of water)? If Yes » What types of life forms could exist at either of these temperatures? State the form of life and the corresponding temperature. If No » Cite the physical reasons why life cannot exist at either of these temperatures. B) Circle the elements that must be present for life to exist. Explain your reasoning for each choice. (listed are hydrogen, potassium, zinc, oxygen, calcium, uranium, magnesium, sulfur, carbon, nitrogen, iron, and sodium)

Discussion Questions Question #4: A) Describe an environment on Earth that would not allow any form of life to exist. Cite specific examples and explain why these environments cannot support life. B) Do scientists have evidence that indicates whether life exists anywhere other than Earth? Explain your reasoning.

Sample Phase Diagram

Density vs. Temperature (water)

Homework Assignment Compare and contrast the differences and similarities between the big bang origin of the universe and the formation of the solar system. minimum 2 typed pages of science-based modeling consider class discussion, material from book, and material from HNRS 227