FIG. 353 shows that, during the Viking primary mission period, large areas of the martian surface were above 273░K when an albedo of 0.25 and a thermal inertia of 6.5 were applied. Although the maximum temperature contour drawn for the Viking landing sites is 270░K, that surface temperature would be exceeded where, because of rocks or dark colorations, the albedo was less than 0.25 and/or the thermal inertia was greater than 6.5. Under these conditions, water would be in liquid form. “Thermal observations made half a century ago54,55,56 established that midday equatorial temperatures rose above the melting point of water.”57 Within large geographic areas, the upper layer of the martian soil exceeds the triple point temperature and pressure for water which, thus, would occur in liquid form at least transitorily in diurnal and seasonal cycles.
LR tests performed on the Death Valley sand dunes, shown in FIG. 4, detected microorganisms in the top one or two millimeters of the sand within one hour, as did tests performed on bare rock. Antimetabolites applied to duplicate samples as controls were effective in preventing evolution of gas, confirming the biological nature of the response. Samples of the top 2 mm of the sand were taken and analyzed by a NASA Jet Propulsion Laboratory (JPL) soil microbiologist. The moisture content and microbial populations reported58 were 0.9%, and 5.10 x 103 aerobic cells per gram, respectively.
The above considerations address the presence of liquid water in terms of the more familiar terrestrial biological needs. Other factors concerning water and biology may apply. Even before the announcements of probable evidence for life in the martian meteorites, the possibility that life once existed on Mars was gaining favor.59 It was generally believed, however, that any such early life forms would have become extinct when liquid water was thought to have become unavailable. Alternatively, it was proposed, some organisms might have retreated to discrete “oases” deep below the surface where liquid water might still exist. Recent findings question the presumption that water activity on Mars is too low to permit aqueous moiety reactions. For example, chlorofluorocarbons are adsorbed onto stratospheric ice crystals which provide a liquid-like moiety for the chlorine to react with ozone.60 Such ice activation may accompany the diurnal frost depositions Viking observed on Mars, making biological reactions possible. Alternatively, water vapor rising from the Mars permafrost may be adsorbed on soil particles to form “double donor waters.” These are reported to exist commonly in ice where they expose very large surfaces as thin films and clusters.61,62 An atomic force microscopy study63 of thin films of water indicates a solvating monolayer of phase I ice on adsorbing surfaces. This water might be available for biological reactions. Duracrust formations on Mars are attributed64 to the solvation and transportation of sulfate to the surface by the vapor flux from the Mars permafrost. This water of solvation might also accommodate biological reactions. Current availability of this solvating factor on Mars was indicated by the Viking GCMS results, which were cited65 as evidence for the availability of water to form the duracrust.
Since Viking, life has been found thriving in extreme environments heretofore believed deadly, including high temperatures and pressures, and even in non-aqueous environments.66 A variety of microorganisms, including synergestic combinations such as lichen, live inside rocks in the dry valleys of the Antarctic67, where precipitation is rare and occurs only as light snow. Aseptically removed from within the rock, scrapings produced the positive LR response included in FIG. 6.
Under extraordinarily harsh environments, many species of bacteria can enter a state in which they catabolize slowly, but neither grow nor divide68 until nutrient concentrations, temperature, and other conditions become favorable. A review69 cites many mechanisms for survival, including some for completely anhydrobiotic cells. Examples70,71 of dormant microorganisms indicate survivals approaching geologically significant time periods. Indeed, bacteria have been reported to have been resuscitated72 after 30 million years of dormancy under highly desiccating conditions.