Astronomy
1st Edition
ISBN: 9781938168284
Author: Andrew Fraknoi; David Morrison; Sidney C. Wolff
Publisher: OpenStax
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Textbook Question
Chapter 30, Problem 29E
Suppose astronomers discover a radio message from a civilization whose planet orbits a star 35 lightyears away. Their message encourages us to send a radio answer, which we decide to do. Suppose our governing bodies take 2 years to decide whether and how to answer. When our answer arrives there, their governing bodies also take two of our years to frame an answer to us. How long after we get their first message can we hope to get their reply to ours? (A question for further thinking: Once communication gets going, should we continue to wait for a reply before we send the next message?)
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Chapter 30 Solutions
Astronomy
Ch. 30 - What is the Copernican principle? Make a list of...Ch. 30 - Where in the solar system (and beyond) have...Ch. 30 - Give a short history of the atoms that are now in...Ch. 30 - What is a biomarker? Give some possible examples...Ch. 30 - Why are Mars and Europa the top targets for the...Ch. 30 - Why is traveling between the stars (by creatures...Ch. 30 - What are the advantages to using radio waves for...Ch. 30 - What is the “cosmic haystack problem”? List as...Ch. 30 - What is a habitable zone?Ch. 30 - Why is the simultaneous detection of methane and...
Ch. 30 - What are two characteristic properties of life...Ch. 30 - What are the three requirements that scientists...Ch. 30 - Can you name five environmental conditions that,...Ch. 30 - Would a human have been possible during the first...Ch. 30 - If we do find life on Mars, what might be some...Ch. 30 - What kind of evidence do you think would convince...Ch. 30 - What are some reasons that more advanced...Ch. 30 - What are some answers to the Fermi paradox? Can...Ch. 30 - Why is there so little evidence of Earth’s...Ch. 30 - Why was the development of photosynthesis a major...Ch. 30 - Does all life on Earth require sunshine?Ch. 30 - Why is life unlikely to be found on the surface of...Ch. 30 - In this chapter, we identify these characteristic...Ch. 30 - Given that no sunlight can penetrate Europa’s ice...Ch. 30 - Why is Saturn’s moon Enceladus such an exciting...Ch. 30 - In addition to an atmosphere dominated by...Ch. 30 - How can a planet’s atmosphere affect the width of...Ch. 30 - Why are we limited to finding life on planets...Ch. 30 - Suppose astronomers discover a radio message from...Ch. 30 - The light a planet receives from the Sun (per...Ch. 30 - Think of our Milky Way Galaxy as a flat disk of...
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