In the early stages of its devolepment which the hot gases condensing and molten matter which was solidifying to form what are rocks, today, the earth acted as the huge factory producing many kinds of compounds . the sources of energy available for the formation of numerous type of molecules were comic rays ultraviolet radiation, electrical discharges such a lightening, radioactivity , and heat from the volcanoes and hot springs. molecules of all sorts were being continuosly created and destroyed due to their state of agitation . the lighter gases of the atmosphere such as hydrogen , helium ,etc.were continuosly created.