Dark matter in the solar system: Hydrogen cyanide polymers

Abstract

Abstract. In the presence of a base such as ammonia liquid HCN (bp 25 °C) polymerizes readily to a black solid from which a yellow-brown powder can be extracted by water and further hydrolyzed to yield c~-amino acids. These macromolecules could be major components of the dark matter observed on many bodies in the outer solar system. The non-volatile black crust of comet Halley, for example, may consist largely of such polymers, since the original presence on cometary nuclei of frozen volatiles such as methane, ammonia, and water makes them possible sites for the formation and condensedphase polymerization of hydrogen cyanide. It seems likely, too, that HCN polymers are among the dark --C=N bearing solids identified spectroscopically by Cruikshank et aL in the dust of some other comets, on the surfaces of several asteroids of spectral class D, within the rings of Uranus, and covering the dark hemisphere of Saturn's satellite Iapetus. HCN polymerization could account also for the yelloworange-brown coloration of Jupiter and Saturn, as well as for the orange haze high in Titan's atmosphere. Implications for prebiotic chemistry are profound. Primitive Earth may have been covered by HCN polymers through cometary bombardment or terrestrial synthesis, producing a proteinaceous matrix that promoted the molecular interactions leading to the emergence of life.

Nitrogen Incorporation in CH4-N2 Photochemical Aerosol Produced by Far Ultraviolet Irradiation

“…The formation of HCN or nitrile-rich materials is of great interest with regard to multiple planetary bodies within the Solar System because of the strong spectral features and prebiological potential of these types of molecules (Matthews, 1992). Thus, it is important to understand the complete range of formation conditions given the wide array of radiation and compositional constraints of different planetary environments.…”

Optical properties of poly-HCN and their astronomical applications

“…Matthews (1,54) proposes that this is due to poly-HCN and generated from HCN in the Titanian atmosphere. In Fig.…”

“…Specifically, claims are made for the dark involatile surface of the nucleus of Comet Halley, D-class asteriods, the rings of Uranus, the dark hemisphere of Iapetus, the orange-brown clouds of Jupiter and Saturn, and the haze of Titan (1)(2)(3).…”

“…72, 678 (1994). Matthews (1992) has proposed that HCN "polymer" is ubiquitous in the solar system. We apply vacuum deposition and spectroscopic techniques previously used on synthetic organic heteropolymers (tholins), kerogens, and meteoritic organic residues to the measurement of the optical constants of poly-HCN in the wavelength range 0.05-40 pm.…”

Exploring the structure of a hydrogen cyanide polymer by electron spin resonance and scanning force microscopy

“…The reaction conditions which produce adenine, when maintained for a period of days, also produce cyanide polymer as a reaction product (Volker 1960). Moreover, what appear to be similar materials can be produced by an electrical discharge in gaseous HCN, or by adding base to liquid HCN (Mathews 1992, Minard et al 1998. In general, the polymeric materials formed in these reactions seem to be heterogeneous in color, structure, and chemical properties depending on the conditions under which the polymer is formed (Ferris et al 1981, Liebman et al 1995, Minard et al 1998.…”