Finding Extraterrestrial Organisms Living on Thermosynthesis

Abstract

During thermal cycling, organisms could live on thermosynthesis, a theoretical mechanism applicable to the origin of life and the early evolution of biological energy conversion. All extraterrestrial ice may be a repository for frozen dead or dormant organisms from earlier stages of evolution. In the presence of a thermal gradient within the ice, organisms might still be harvesting energy from thermosynthesis. Possible habitats for thermosynthesizers can be found throughout the Solar System, particularly in the cold traps on Mercury and the Moon, convecting waters on Mars, the oceans on moons in the outer Solar System, and smaller bodies rotating in the sunlight such as cosmic dust, meteorites, asteroids, and comets. A general strategy for detecting thermosynthetic organisms on Earth is offered, and highlights of current and upcoming robotic exploratory missions relevant to the detection of thermosynthesis are reviewed.

Sorption heat engines: Simple inanimate negative entropy generators

“…8), similarities that are in accordance with Orgel's continuity principle during evolution [92]. In the thermosynthesis model for the emergence of bioenergetics, the first enzyme was proposed to have been a heat engine driven by thermal cycling in convecting volcanic hot springs [47,[93][94][95][96]. This first enzyme dehydrated bound reactants (or 'substrates' in the terminology of biochemistry), binding them at a low temperature in the enzymatic cleft in which water was absent, performing a dehydration reaction, and releasing the condensation product by a thermal unfolding at a higher temperature.…”

“…The emergence made the acquisition of many proteins/enzymes possible, which allowed in turn the emergence of fermentation and photosynthesis. For the latter a model has been given that starts with a heat engine using the thermotropic lipid phase transition in a biomembrane [94,95,98,99]. Because of the similarities in its chemiosmotic machinery, respiration could easily have evolved from photosynthesis -and vice versa.…”

Emergence of Animals from Heat Engines – Part 1. Before the Snowball Earths

“…This 'membrane-associated thermosynthesis' (MTS) is a proposed progenitor of bacterial photosynthesis, with as an intermediate link a mechanism based on a light-induced dipole potential effected by light-dark cycling [6,85,86]. An early ATP Synthase would have been able to vary the coupling ratio, for instance with the temperature.…”

The prospect of alien life in exotic forms on other worlds

“…In his model, electrogenic ATPases would convert the electrical energy gained by thermosynthesis into ATP if their activity and stoichiometry were properly regulated (Muller 1993). If correct, thermosynthesis could be a plausible basic pathway of metabolism for early organisms on Earth, possibly a progenitor of bacterial photosynthesis (Muller 1995(Muller , 2003, and an option for possible life on other worlds.…”