Sample Questions (exam)

Life in the Universe: Drake Equation & Fermi Paradox

Some of the following is an expansion of earlier material. The material covered since Test 2 is mainly Jovian moons, interstellar travel, and SETI and CETI.

• What is the Drake Equation? What are the different factors contained in the Drake Equation? Which are astronomical factors? Which are biological factors? Which are sociological factors? Are there factors that are blends of the preceding classifications? How well-determined is the solution to the Drake Equation?
• Describe the parts of the Drake Equation that can be determined from astrophysical observation. How are these factors determined and what are their values? What is likely to be the most well-determined term in the Drake Equation? Which are the poorly determined factors?
• What is the Habitable Zone? What determines the size of the Habitable Zone? How many planets in our Solar System are in the Habitable Zone? Which planets are in the Habitable Zone? Describe the differences between Venus, Earth, and Mars in the context of Habitable Zone? What caused Venus, Earth, and Mars to evolve so differently?
• Roughly how many extra-Solar planets have been discovered since 1995? What are the methods used to find extra-Solar planets? Describe the two methods brought up in class. Which method has been used to discover the most extra-Solar planets?
• How many extraterrestrial civilizations are there in our Galaxy based on the Drake Equation? Give your assumptions (assumed values for the individual terms)? Why are the results so uncertain? What is the Kepler satelllite? Has Kepler discovered any planets in the Habitable Zone?
• Venus, Earth, and Mars were likely quite similar at birth and yet, today, they have grossly different atmospheres and surface conditions. Briefly sketch the atmospheric evolution of the Earth and then point out why Venus, Earth, and Mars turned out so differently.
• What evidence is that there Mars once had a much more lush environment in the past than today (that is, what is the evidence for water on Mars?
• Describe the Viking biology experiments. Describe the outcome of the Viking biology experiments. What is the current take on the results of the Viking life experiments? Be sure to mention how the Phoenix and Curiosity results have changed our views of the Viking results.
• What is LAWKI? How did the idea of LAWKI influence the design of the Viking experiments? What is the Gaia Hypothesis?
• CETI and SETI. For what do the acronyms CETI and SETI stand? Are we engaged in CETI? In what ways? Are attempts inadvertent? Describe the Arecibo message to M13? How was it sent and how was it to be interpreted? What are the problems in formulating our attempts to communicate with extraterrestrials? Do we want to communicate with extraterrestrials? Do you think the Voyager plaques (and the earlier Pioneer plaques) are useful? Why or why not?
• What is the Fermi Paradox? Describe the Fermi Paradox. Are there resolutions for the Fermi Paradox? What are Neumann machines?
• What is the major difficuty when considering interstellar travel? Cite examples of how difficult it will be. Describe the Twin Paradox. Describe the concept of a black hole? What is a wormohole? How would wormholes help up to explore the galaxy (or Universe)? What is a major problem with traversing a wormhole? How could the problem be overcome? Are clocks affected by whether a person is still or moving? Are clocks affected by the strenth of gravity about them? In both, if yes, what kind of effects are seen?
• We earlier defined Habitable Zone of a system as where the energy a planet receives from its pair is just so in the sense that it allows the planet to sustain large amounts of water in its liquid state. We now recognize that habitable zone concepts need modifiction. How do Europa and Enceladus suggest we expand our thinking on Habitable Zones? What is tidal forcing? Why are Europa and Enceladus now thought to be further interesting objects for studies of extraterrestrial life? What are the recent observations of Enceladus that suggest conditions for life exist on Enceladus? What is methanogenesis?
• Venus, Earth, and Mars were likely quite similar at birth and yet, today, they have grossly different atmospheres and surface conditions. Briefly sketch the atmospheric evolution of the Earth and then point out why Venus, Earth, and Mars turned out so differently.
• What evidence is that there Mars once had a much more lush environment in the past than today (that is, what is the evidence for water on Mars?
• Describe the Greenhouse Effect.
• What is the Faint Young Sun Problem? What is the likely solution to the Faint Young Sun Problem? What is meant by equilibrium temperature?
• What is the water trap?