Haldane coined the term 'prebiotic soup' or 'prebiotic atmosphere' that consisted of an abundance of methane, ammonia, and water. This term became a powerful symbol of the Oparin-Haldane view of the origin of life. In 1953, two scientists set out to test Oparin and Haldane's hypothesis. Harold Urey and his student Stanley Miller tried to calculate the chemical constituents of the atmosphere of the early Earth. They based their calculations on the view that the early atmosphere was reducing.