http://digfir-published.macmillanusa.com/deu6e/deu6e_ch15_1.htmlChapter Introduction54adc3ea757a2e8957000000
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http://digfir-published.macmillanusa.com/deu6e/deu6e_ch15_2.html15-1 Astrobiology connects the cosmos and the origins of life54adc3ea757a2e8957000000
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http://digfir-published.macmillanusa.com/deu6e/deu6e_ch15_3.html15-2 The existence of life depends on chemical and physical properties of matter54adc3ea757a2e8957000000
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http://digfir-published.macmillanusa.com/deu6e/deu6e_ch15_4.html15-3 Evidence is mounting that life might exist elsewhere in our solar system54adc3ea757a2e8957000000
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http://digfir-published.macmillanusa.com/deu6e/deu6e_ch15_5.html15-4 Searches for advanced civilizations try to detect their radio signals54adc3ea757a2e8957000000
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http://digfir-published.macmillanusa.com/deu6e/deu6e_ch15_6.html15-5 The Drake equation: How many civilizations are likely to exist in the Milky Way?54adc3ea757a2e8957000000
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http://digfir-published.macmillanusa.com/deu6e/deu6e_ch15_7.html15-6 Humans have been sending signals into space for more than a century54adc3ea757a2e8957000000
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http://digfir-published.macmillanusa.com/deu6e/deu6e_ch15_8.htmlSUMMARY OF KEY IDEAS54adc3ea757a2e8957000000
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http://digfir-published.macmillanusa.com/deu6e/deu6e_ch15_9.htmlEnd of Chapter Questions54adc3ea757a2e8957000000
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