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Most SF movies prefer to show only planets of the terrestrial type, in order to allow the actors to roam freely there and show their uncovered faces to the cameras. At most there have been a few novels or movies that have attempted to describe less familiar landscapes, such as those that could be encountered on the satellites of Jupiter or Saturn. There have been a few SF stories about planets made of some exotic materials, like diamond or some metals or some superheavy elements, but those were complete fantastic stories without any scientific base and the planets described there could not exist anywhere in the known universe. I am not aware of any novel or movie that has tried to show a completely alien planet, of the kind that could not exist in the Solar System, but which could really exist in other stellar systems. A planet from a stellar system with a high C/O ratio might have rocks made of abrasive carborundum (i.e. silicon carbide), an atmosphere composed of methane, carbon monoxide and carbon dioxide and an ocean containing a mixture of hydrocarbons, like some kind of petroleum. If there would be life forms there, they could have very significant differences from the life forms that can appear in the stellar systems of the Solar type. Here on Earth, an essential chemical property for life is the distinction between hydrophobic and hydrophilic substances, i.e. the fact that water and oil do not mix, which enables the existence of the cells of all living beings, which are made of hydrophobic membranes that partition a hydrophilic solvent. Perhaps on a planet with reversed abundances, where hydrocarbons are very abundant and water is scarce, one could have reversed cell structures, with a hydrophobic solvent partitioned by hydrophilic membranes, though it is not clear if such structures can be made stable. In such a place, most metals would be present in easy to reduce compounds, so living beings with metallic skeletons might exist. (Though at least for now, the appearance of life in such stellar systems seems less likely. In the terrestrial kind of planets, the energy flux for the appearance of life has been provided mainly by the free dihydrogen generated by the oxidation of Fe(II) ions to Fe(III) ions by water, in volcanoes and in hydrothermal vents. It is not known whether some equivalent energy source can exist in a place with little water, but abundant hydrocarbons.) An SF novel or movie with such a subject, about the exploration of a completely unfamiliar world, could be interesting, but this kind of SF novels were written only up to around a half of century ago. Most modern SF novels or movies no longer try to analyze the consequences of intriguing scientific hypotheses, but they choose the lazier way of just transposing traditional fantastic stories into a pseudo-scientific framework. |