At first, it was thought that the Earth's atmosphere consisted of hydrogen compounds—methane, ammonia and water vapour—and that life began under such reducing conditions, which are conducive to the formation of organic molecules.
Prvo se mislilo da se Zemljina atmosfera sastojala od hidirda - metana, amonijaka i vodene pare - i da je život počeo u takvim uvjetima pogodnim za formiranje organskih molekula.