CHAP. 32] THE ORIGIN OF LIFE 863 



during the day. The colors of Mars have been observed for many years by many 

 people. The planet exhibits seasonal changes: green or bluish in the spring and 

 brown and reddish in the autumn. Sinton (1959) has observed absorptions at 

 3.43 [JL, 3.56 II and 3.67 [i in the reflected light of Mars. The 3.43 [j. absorption 

 corresponds to the C — H stretching frequency of most organic compounds at 

 this wavelength. The changing colors of Mars and the 3.5 {jl absorption are the 

 best evidence, however poor, for the existence of life on the planet. One thing 

 that can be stated with confidence is that if life exists there, then hquid water 

 must have been present on the planet in the past, since it is difficult to believe 

 that life could have evolved in its absence. If this was so, water must have 

 escaped from the planet, as very little water remains there now, and no hquid 

 water has been observed. Hence, oxygen atoms must escape from the planet. 

 This is possible if the high atmosphere has a temperature of 2000°K, and this is 

 not impossible in view of the high temperatures in the high atmosphere of the 

 Earth. 



Surely one of the most marveUous feats of 20th-century science would be the 

 firm proof that life exists on another planet. All the projected space flights and 

 the high costs of such development would be fully justified if they were able to 

 estabhsh the existence of life on either Mars or Venus. In that case, the thesis 

 that life develops spontaneously when the conditions are favorable would be far 

 more firmly established, and our whole view of the problem of the origin of 

 life would be confirmed. 



References 



Abelson, P. H., 1956. Paleobiochemistry: Inorganic synthesis of amino acids. Carnegie 



Inst. Wash. Year Book, 55, 171. 

 Abelson, P. H., 1956a. Amino acids formed in "primitive atmospheres". Science, 124, 935. 

 Abelson, P. H., 1957. Some aspects of paleobiochemistry. Ann. N.Y. Acad. Sci., 69, 276. 

 Bahadur, K.. 1954. Photosynthesis of amino acids from paraformaldehyde and potassium 



nitrate. Nature, 173, 1141. Also in Oparin et al. (Eds.), Proc. 1st Intern. Symp. Origin of 



Life on the Earth. Pergamon Press, London, 1959, p. 140. 

 Bernal, .J. D., 1949. The physical basis of life. Proc. Phys. Soc. London, 62A, 537; 62B, 



597. 

 Bullard, E., 1954. The interior of the earth. In G. P. Kuiper (Ed.), The Earth as a Planet, 



Chicago Univ. Press, Chicago, 111., 110. 

 Calvin, M., 1956. Chemical evolution and the origin of life. Amer. Set., 44, 248. 

 Curtis, A. R. and R. M. Goody. 1956. Thermal radiation in the upper atmosphere. Proc. 



Roy. Soc. London, A236, 193. 

 Dose, K. and B. Rajewsky, 1957. Strahlenchemische Bildung von Aminen und Amino- 



carbonsauren. Biochim. Biophys. Acta, 25, 225. 

 Ellenbogen, E., 1958. Photochemical synthesis of amino acids. Abstr. Amer. Chem. Soc. 



Meeting, Chicago, 1958, p. 47C; and personal commimications. 

 Fox, S. W. et al., 1956. On biochemical origins and optical activity. Science, 124, 923; 



Ann. N.Y. Acad. Sci., 69. 328 (1957); J. Chem. Ed. 34, 472 (1957). 

 Garrison, W. M., D. C. Morrison, J. G. Hamilton, A. A. Benson and M. Calvin, 1951. 



Redviction of carbon dioxide in aqueous solutions by ionizing radiation. Science, 114, 



416. 



