Abstract
Extremophiles thrive on the edge of temperature, pH, pressure, hypersalinity, dryness, and desiccation. Such microorganisms may resemble the first living organisms which evolved on the early Earth. They may also serve as analogues of microbes on other worlds. Some celestial bodies may provide conditions for life, such as liquid water and other essential ingredients for microbial life. Consequently, life may exist elsewhere in the Solar System, even though the environments available may be more extreme than those on Earth. Wherever there is life we expect the presence of microbial life such as prokaryotic microorganisms. Prokaryotes have thrived on Earth at least since the period corresponding to 3.5 to 3.8 billion years before the present (Ga BP). They have dominated our biosphere during its first 2 Ga, even before the first eukaryote appeared, and have been the least affected through major climatic astronomical and geological events in the early Earth. Therefore, prokaryotes are the most likely candidates for a presumed biota on other worlds (although eukaryotes are also a possibility). The most promising worlds, which may harbor living microbes are Mars and the Jovian moon Europa.
Original language | English |
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Pages (from-to) | 255-260 |
Number of pages | 6 |
Journal | European Space Agency, (Special Publication) ESA SP |
Issue number | 496 |
State | Published - 2001 |
Event | 1st European Workshop EXO-/ASTRO-BIOLOGY - Frascati, Italy Duration: 21 May 2001 → 23 May 2001 |