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The search for intelligence beyond Earth has long entranced humans. According to Jon Gertner, a regular contributor to The New York Times Magazine, this search has been defined \u201cby an assumption that extraterrestrials would have developed radio technologies akin to what humans have created.\u201d\n\nHowever, Mr. Gertner writes, \u201crather than looking for direct calls to Earth, telescopes now sweep the sky, searching billions of frequencies simultaneously, for electronic signals whose origins can\u2019t be explained by celestial phenomena.\u201d\n\nWhat scientists are most excited about is the prospect of other planets\u2019 civilizations being able to create the same \u201ctelltale chemical and electromagnetic signs,\u201d or, as they are now called, \u201ctechnosignatures.\u201d