107 



Another possible record from which to study the composition 

 of the early solar system is meteorites. Consideration of models for 

 the origin of solid bodies in the solar system, and data obtained from 

 the study of meteorites raise a number of important issues. 



Differentiation and hydrothermal processes occurred on small 

 bodies very early in the chemical evolution of the solar system. Simi- 

 lar processes took place on the primitive Earth, but the chronology 

 and the consequences of these processes on the thermal, geochemi- 

 cal, and atmospheric evolution of the Earth's prebiotic environment 

 are major unknowns, and require elucidation. Insofar as processes 

 operating on meteorite parent bodies can be generalized or related to 

 similar processes on the Earth, then continued study of their mani- 

 festations in meteorites will contribute significantly to understanding 

 the environment in which life originated. 



The hypothesis that an interstellar cloud of dust and gas pro- 

 vided the spawning ground for the entire solar system is generally 

 accepted. Models based on this hypothesis hold promise of providing 

 a coherent framework for understanding the origin of the solar sys- 

 tem and of, ultimately, life itself. In this context, relationships 

 should exist between the organic matter in interstellar clouds, 

 comets, and carbonaceous meteorites; thus, research efforts aimed at 

 elucidating the nature of the relationship should be strongly encour- 

 aged. Contributions to the confirmation or denial of models for the 

 origin of bodies in the solar system should become a major objective 

 of organic chemical evolution research. 



Planetesimals resembling meteorites and their parent bodies are 

 believed to have supplied the building blocks for formation of the 

 planets. Carbonaceous meteoritic material would have contributed 

 significantly to the crust, mantle, and inventory of volatiles of the 

 primitive Earth. How these contributions influenced its physical- 

 chemical evolution and, therefore, the setting in which life origi- 

 nated should be of major concern in the study of the origin of life. 



We still don't know where the carbonaceous meteorites came 

 from; however, asteroids represent prime candidates. We do know 

 that there are large numbers of dark asteroids whose reflectance 

 spectra resemble those of carbonaceous chondrites. Is there a connec- 

 tion? Do these objects also contain organic compounds? 



From the above considerations it is obvious that detailed 

 studies of meteorites should be continued. And, a mission to the 



