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adreamer adreamer
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6 years ago
Approximately how soon might we expect an immediate response from a civilization that received the signal we sent to the globular cluster M13 (21,000 light-years away) in 1974?
A) 84,000 years
B) 21,000 years
C) 10,500 years
D) 42,000 years
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Life in the Universe

Life in the Universe


Edition: 4th
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19Clyde19Clyde
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adreamer Author
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6 years ago
Thanks!
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