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A search for life on Earth from the Galileo spacecraft

Naturevolume 365pages715721 (1993) | Download Citation

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Abstract

In its December 1990 fly-by of Earth, the Galileo spacecraft found evidence of abundant gaseous oxygen, a widely distributed surface pigment with a sharp absorption edge in the red part of the visible spectrum, and atmospheric methane in extreme thermodynamic disequilibrium; together, these are strongly suggestive of life on Earth. Moreover, the presence of narrow-band, pulsed, amplitude-modulated radio transmission seems uniquely attributable to intelligence. These observations constitute a control experiment for the search for extraterrestrial life by modern interplanetary spacecraft.

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Affiliations

  1. Laboratory for Planetary Studies, Cornell University, Ithaca, New York, 14853, USA

    • Carl Sagan
    •  & W. Reid Thompson
  2. Atmospheric and Cometary Sciences Section, Jet Propulsion Laboratory, Pasadena, California, 91109, USA

    • Robert Carlson
  3. Department of Physics and Astronomy, University of Iowa, Iowa City, Iowa, 52242-1479, USA

    • Donald Gurnett
  4. Laboratory for Atmospheric and Space Physics, University of Colorado, Boulder, Colorado, 80309, USA

    • Charles Hord

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