  There is increasingly more evidence being accumulated for the occurrence of
large amounts of organic material in the cosmos, particularly in the form of
aromatic compounds. These molecules can be found on the surface of Earth and
Mars, in the atmospheres of the larger planets and on many of their satellites,
on asteroids, comets, meteorites, the atmospheres of red giant stars,
interstellar nebulae, and in the spiral arms of galaxies. Many of these
environments are expected to be of low temperature and pressure, implying that
the Gibbs free energy for the formation of these complex molecules should be
positive and large, suggesting that their existence could only be attributed to
non-equilibrium thermodynamic processes. In this article we first review the
evidence for the abundance of these molecules in the cosmos and then describe
how the ubiquity can be explained from within the framework of non-equilibrium
thermodynamics on the basis of the catalytic properties of these pigment
molecules in dissipating photons of the ultraviolet and visible emission
spectra of neighboring stars, leading to greater local entropy production. A
relation between the maximum wavelength of absorption of these organic pigments
and the corresponding stellar photon environment, provides a guide to
determining which aromatic compounds are most probable in a given stellar
neighborhood, a postulate that can be verified on Earth. It is suggested that
at least some of the baryonic dark matter may be associated with these
molecules which emit in the extreme infrared with many, but weak, emission
lines, thus so far escaping detection. This thermodynamic explanation for the
ubiquity of these organic molecules also has relevance to the possibility of
life, both as we know it, and as we may not know it, throughout the universe.
