Purchase of this book includes free trial access to www.million-books.com where you can read more than a million books for free. This is an OCR edition with typos. Excerpt from book: H. Protection of Deposited Molecules and Present Location of Lunar Deposits of Organic Matter During the time of deposition, the lunar atmosphere would have inhibited thermo- and photo-dissociation of the deposited molecules. As the secondary lunar atmosphere gradually escaped to space, and outgassing declined, the rate of atmospheric organic synthesis decreased and the penetration of short wavelength radiation to the surface increased. In addition, the surface temperature gradually rose, due both to the loss of the insulating atmosphere, and to radioactive heating. The effect of heat and ultraviolet light on the molecules described above is most remarkable. Although the second law of thermodynamics is obeyed, a large fraction of the molecules, with activation energies supplied, partake in organic syntheses of a higher order of complexity. Polypeptides arise from amino acids, hydrocarbon dimers and trimers form long- chain polymers, and in general very complex organic molecules are constructed (v., e.g., Oparin, 1957; Fox, 1956). Finally, because complex molecules are more resistant to heat and radiation than are simpler molecules (at least in part due to the Franck- Rabinowitch cage effect), the syntheses are biased towards the net production of the most complex organic molecules (Gordy, Ard, and Shields, 1955; Sagan, 1957). Although continued radiation and high temperatures would lead to the eventual destruction of all these molecules, we must remember that meteoritic matter was falling into the lunar atmosphere throughout the period of organic synthesis. Whipple (1959) estimates that about 50 gm cm2 of meteoritic matter falls on the Moon each 108 years at present rates of infall. In addition, it is almost certain that the rate of meteoritic infall on the Moon in primi...