Astrobiology: From Extremophiles in the Solar System to Extraterrestrial Civilizations

Abstract

Life on Earth is ubiquitous. Most of the organisms that we know thrive in normal environments that we consider to be ambient habitats. Extremophiles are among the microorganisms living on the edge of life under severe conditions. In recent years microorganisms have been discovered living in extreme environments, such as very high temperature (up to 115{\textdegree}C), and also at very low temperature (∼ minus 20{\textdegree}C). In addition, they can also withstand a variety of stresses, amongst them we mention both ends of the pH range; very strong acidity vs. high alkalinity; saturated salt solutions and high hydrostatic pressure. Astrobiology considers the possibility that extraterrestrial civilizations may be present in some exoplanets in the large suite that has been discovered so far. The instruments of research are radio telescopes. Astrobiology also raises the possibility of life elsewhere in the Solar System. (The most promising examples are Mars, Europa, and possibly Titan and Enceladus). We suggest that if microbial communities can thrive under extreme conditions on Earth, they could also emerge on extraterrestrial environments.