A search for life on Earth from the Galileo spacecraft
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.
- Publication:
-
Nature
- Pub Date:
- October 1993
- DOI:
- 10.1038/365715a0
- Bibcode:
- 1993Natur.365..715S