Concept explainers
Explain all answers clearly, with complete sentences and proper essay structure if needed. An asterisk (*) designates a quantitative problem, for which you should show all your work.
*23. SET! Search. Suppose there are 10.000 civilizations broadcasting radio signals in the Milky Way Galaxy right now. On average, how many stars would we have to search before we would expect to hear a signal? Assume there are 400 billion stars in the galaxy. How would the answer change if there were only 100 civilizations instead of 10,000?
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