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Providing evidence for possible oil-type occurrences on Mars means providing an indication for the past life on Mars. We do this via analysis of the combed (aligned) gravity strike angles, one of the gravity (gravitational) aspects (descriptors) derived from one of the recent gravitational field models of Mars, currently having the highest accessible precision and resolution. After intensive testing for features on the Earth and the Moon, the gravity aspects are applied for Mars. We detect candidates for the groundwater/hydrocarbon/mud/petroleum-bearing sites in the largest areas with as many as possible combed gravity strike angles, uniformly ordered into ‘plates’. They appear mainly but not only in the hypothetical northern Martian palaeo-ocean (the northern lowlands). It turns out that the combed strike angles are sensitive not only to uniformly ordered sediments of the basins, but also to supposed lahars.
The concept of planetary intelligence as collective intelligence is used to consider possible evolutionary paths of biotechnospheres that emerge on the intersection of the technosphere with the biosphere and support coupling of the technosphere with the biosphere, thus affecting planetary evolution. In mature biotechnospheres, the intelligence of technologies and the intelligence of life forms, including engineered life forms, could act in concert to perform various tasks (e.g. monitoring planetary biospheres and environments; restoring planetary environments and biodiversity; steading planetary environments; providing support for space missions; terraforming cosmic objects). Space exploration can expand biotechnospheres beyond planets and create cosmic ecosystems encompassing planets and other cosmic objects; biotechnospheres, spacecraft and the environments of near-planetary, interplanetary space or interstellar space. Humankind, other civilizations or their intelligent machines may produce biotechnosignatures (i.e. observables and artefacts of biotechnospheres) in the Solar System and beyond. I propose ten possible biotechnosignatures and strategies for the search for these biotechnosignatures in situ and over interstellar distances. For example, if a non-human advanced civilization existed and built biotechnospheres on Earth in the past, its biotechnospheres could use engineered bacteria and the descendants of that bacteria could currently exist on Earth and have properties pertaining to the functions of the ancient bacteria in the biotechnospheres (such properties are proposed and discussed); intelligent technologies created by the ancient civilization could migrate to the Solar System's outer regions (possible scenarios of their migration and their technosignatures and biotechnosignatures are discussed); these two scenarios are described as the Cosmic Descendants hypothesis. Interstellar asteroids, free-floating planets, spacecraft and objects gravitationally bound to flyby stars might carry extraterrestrial biotechnospheres and pass through the Solar System. In connection to the fate of post-main-sequence stars and their Oort clouds, the probability for interstellar asteroids to carry biotechnospheres or to be interstellar spacecraft is estimated as very low.
Discoveries of transient liquid water in the Martian polar caps and the presence of liquid lakes and subsurface oceans in icy satellites have increased the interest of scientists in the capabilities of terrestrial extremophiles to grow and remain metabolically active in these extreme environments. The principal goal of this research is to understand the metabolic capacity of the anaerobic psychrophile, Desulfotalea psychrophila, cultured at subfreezing temperatures in media containing various concentrations of sulphate minerals. In this regard, our experiments focused on the detection of D. psychrophila survival and active metabolism, employing a biochamber that can recreate Martian temperatures. Using standard bacteriological methods for determining growth, combined with molecular and enzymatic determination of sulphate reduction, we have found that D. psychrophila is capable to carry out biological processes at temperatures down to −5°C, at concentrations that range from 0.35 to 18 wt% of MgSO4, 0.1 wt% of CaSO4 and 10 to 14 wt% of FeSO4 in which the highest sulphate concentration gradually returned the biosynthetic rate to basal limits, and the lowest temperature decreased bacterial cell division. These chemical salts, whose ions are classified as chaotropes, are known to act by maintaining water molecules in liquid state at subfreezing temperatures and by altering the stability of cellular components. This ‘chaotropic effect’ could potentially benefit the microbial metabolic activity up to a concentration in which cellular viability is jeopardized. Consequently, our hypothesis is directed towards the detection of metabolic activity as an indirect measurement of the potential influence of these ions in the flexibility/functionality of biological structures that at cold temperatures are highly rigid, compact and partially/non-functional due to water freezing. Studies of this type of microorganism are critical considering the possibility of survival and colonization of psychrophilic sulphate reducers in other planets and icy satellites.
This paper provides an overview of recent historical research regarding scientifically-informed challenges to the idea that the stars are other suns orbited by other inhabited earths – an idea that came to be known as ‘the Plurality of Worlds’. Johannes Kepler in the 17th century, Jacques Cassini in the 18th and William Whewell in the 19th each argued against ‘pluralism’ based on what in their respective times was solid science. Nevertheless, pluralism remained popular despite these and other scientific challenges. This history will be of interest to the astronomical community so that it is better positioned to avoid difficulties should the historical trajectory of pluralism continue, especially as it persists in the popular imagination.