Chapter Review

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Vocabulary

Review Questions

1. Which stars have large habitable zones and which ones have small habitable zones?
2. Why should the search for life be narrowed to stars with masses 0.5 to 1.4 solar masses?
3. What spectral types of stars are excluded from S.E.T.I.?
4. What is the range of temperatures for stars included in S.E.T.I.?
5. Why are binary or multiple star systems usually excluded from S.E.T.I. searches? Which type of binary system might be good ones to check out?
6. What are the characteristics of life?
7. What is the definition of life? How do you know if something is living?
8. Where can life exist?
9. How will we be able to detect if life exists on an exoplanet?
10. Where in the Galaxy should the search be concentrated (bulge, stellar halo, disk, dark matter halo) and why?
11. Where is extraterrestrial intelligent life expected to be found?
12. How do we estimate how many other communicating civilizations we expect to find? What parts of that estimate are fairly well-known, what parts are much more uncertain, and what makes the terms more or less certain?
13. What do you find when you plug in values for the Drake Equation?
14. What frequency or wavelength bands are the focus of current SETI searches and why?
15. What are the facts and assumptions behind Fermi's Question and what are some possible reasons why we haven't found signs of an extra-terrestrial civilization?

References and Web Links

1. NASA Astrobiology Program. NASA's Astrobiology Program addresses three fundamental questions: How does life begin and evolve? Is there life beyond Earth and, if so, how can we detect it? What is the future of life on Earth and in the universe? The nine elements in the NASA Astrobiology Program include:
   1. NASA Astrobiology Institute
   2. Exobiology and Evolutionary Biology Program
   3. Habitable Worlds Program
   4. Emerging Worlds Program
   5. Planetary Science and Technology Through Analog Research Program (PSTAR)
   6. MatiSSE
   7. PICASSO
   8. Laboratory Analysis of Returned Samples Program (LARS)
   9. Nexus of Exoplanet Systems Science (NExSS) project
2. The Berkeley SERENDIP homepage discusses U.C. Berkeley's contribution to the SETI project (will display in another window).
3. The SETI Institute's homepage. Will display in another window.
4. Robert Hazen's "Origin of Life" lectures with the Teaching Company.
5. My list of information about the detection of other planets.
6. PBS NOVA's "Finding Life Beyond Earth" video. See also the PBS LearningMedia California lesson plans for "Finding Life Beyond Earth".
7. Life in the Universe edited by John Billinham (MIT Press: Cambridge, MA, 1982). Topics covered:
   • The Origin of Life---organic chemical evolution, role of sulfur and water.
   • Life-Supporting Environments---atmospheres, continents, oceans, climatic stability, stellar influences, planetary orbits (in single and multiple star systems), oxygen's role, detecting extrasolar planets.
   • Evolution of Complex Life in the Galaxy---protein synthesis, multicellular organisms, development of intelligence and technology, development of life elsewhere in the Galaxy, biochemical keys, development of land plants and role of gravity, how does rise of homo sapiens and our future fit the evolution of intelligent life theories.
   • Detectability of Technological Civilizations---finding suitable stars, manifestations of advanced civilizations, search strategies, eavesdropping and our radio leakage, plan for SETI.
8. Scientific American October 1994 issue. Entire issue devoted to extraterrestrial life. Topics covered:
   • The Evolution of the Universe
   • The Earth's Elements
   • The Evolution of the Earth
   • The Origin of Life on the Earth
   • The Evolution of Life on the Earth
   • The Search for Extraterrestrial Life
   • The Emergence of Intelligence
   • Future of Homo Sapiens---Merging of Nanocomputer circuitry With the Human Brain
   • Sustaining Life on the Earth
9. Paul Patton, The Three Suns of Centaurus in Astronomy Magazine January 1982, pp. 6 - 17. He talks about the stars themselves and also about stable planet orbits. He then discusses life zones (``ecospheres''), possible types of intelligent life (very speculative!), and Project Daedalus and other starships.

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last updated: May 21, 2019