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费米悖论
The Doctor and His Wife answered the Fermi Paradox: the alien civilization was too developed to encounter a crisis and gave up visiting Earth
费米悖论
Alien civilizations
恩里科·费米
earth
05-05
![The Doctor and His Wife answered the Fermi Paradox: the alien civilization was too developed to encounter a crisis and gave up visiting Earth[fig]](data:image/gif;base64,R0lGODlhAQABAIAAAP///wAAACwAAAAAAQABAAACAkQBADs=)