Chapter #17 Intellegent Life in the Universe.


1. How long have Homo sapiens been on Earth? What percentage of the Earths existence is this? (page 278)

2. What caused the development of increased intelligence of Homo sapiens compared with its ancestors? When did this development occur? (page 278)

3. What changes in environmental characteristics is likely to have driven the major physiological changes that lead to increased development of early species of primates and human ancestors? (page 279)

4. If we look at the diversity and history of life on Earth, does the development of intelligence appear to be a high or low evolutionary imperative? (page 279 - 282)

5. According to Jakosky how many stars are there in our galaxy? What variable is represents this value in the drake equation? If the age of the galaxy is 10 by, and we assume a uniform rate of star formation, at what rate have stars been forming in our galaxy? (page 283)

6. Approximately what percentage of all stars are thought to be members of a multiple star system? What implication does this have on the variable fp? (page 284)

7. How would the presence of a large gas giant planet like Jupiter cause the estimated value for n to be small, and how the presence of such a planet cause the estimated value for n to be large. (page 284)

8. How does considering the time it took for intelligent life to develop on the Earth affect the estimation of the variable fi? (page 284)

9. What are the range of results to the Drake equation that result from the estimated high and low values given by Jakosky? Interpret these numbers in terms of how many galaxies or stars would need to be looked at if we were to find intelligent life. (page 285)

10. Describe the Fermi Paradox and the predominant possible scenarios that solve the paradox. (page 285 &endash; 286)

11. What type of signal or scientist searching for (or broadcasting) to establish (or contact) if there is intelligent life in the universe? Why is this form of light preferred over visible light? (page 287)

12. Why are the wavelengths between 21-cm and 18-cm thought to be the range of light to look for transmissions from extra terrestrial intelligence? (page 288)