The low temperature organic chemistry of Titan's geofluid

Exobiological Implications of a Possible Ammonia–Water Ocean inside Titan

“…In the absence of evidence to the contrary we must assume that if there ever was life on Titan it originated in the same way as it did on Earth, plausibly through a period of abiological chemogeny-yielding the building blocks of proteins and DNA-and then via a set of as yet unknown steps to the living state (see, for example, Laczano and Miller 1996, Lifson 1997, Freeland et al 1999. Although these theories call for a biochemistry based on water, it has been suggested by Raulin et al (1995) that "ammono" analogs of terrestrial biomolecules (in which oxygen atoms are replaced by NH groups) might yield an equally viable pseudo-biochemistry. This could prove to be a fruitful avenue for future investigation.…”

“…The action of ionizing radiation (Sagan and Thompson 1984), of lighting (Borucki et al 1984), and of meteorite impacts Lewis 1987, Thompson et al 1992) is very likely to have driven an exotic prebiological chemistry, perhaps as far as the amino acid/nucleotide base stage. Organic chemistry on Titan's surface, in the atmosphere, and in the liquid hydrocarbon lakes thought to exist in order to sustain methane photolysis has been reviewed in a considerable amount of detail (Gupta et al 1981, Khare et al 1986, Raulin 1987, Raulin et al 1995. However, with a surface temperature of ∼95 K, it is only sporadic events (lightning strikes, etc.)…”

“…that are able to catalyze any extensive chemical activity. The half-lives of simple reactions-the polymerisation of HCN for example-are of the order of the age of the Solar System in the absence of a sustained driving force (Raulin et al 1995). The absence of water also provides a serious stumbling block to the formation of biological molecules (unless one accepts the possibility of an ammonia based biochemistry as mentioned earlier).…”

Ionizing Radiation and Life

“…Although these orbital detections of large species are from the upper ionosphere, similar organics are also expected to be produced in the lower, CR-generated ionosphere, and so contribute to the organic inventory and biological potential of Titan's surface environment. Cosmic rays that penetrate through the atmosphere may also induce additional organic synthesis on the surface, especially in the polar lakes of methane and ethane , such as driving the polymerization of HCN (Raulin et al, 1995).…”

The prospect of alien life in exotic forms on other worlds

“…Haldane (1954) pointed out ammonia analogues to water and suggested the possibility of building proteins, nucleic acids, and polypeptides within a liquid ammonia solvent. Raulin et al (1995) suggested that "ammono" analogues of Terran biomolecules in which oxygen atoms are replaced by NH groups might yield an equally viable pseudobiochemistry. Firsoff (1963) went into some detail showing similarities of synthesis reactions in water-based, ammonia-based, and water-ammonia mixtures.…”