Stanley Miller and Harold Urey supported the chemical origin of life proposed by Haldane and Oparin. The famous Miller-Urey experiment in 1953 in which primordial atmosphere was simulated, suggested that lightning might have helped to create the important building blocks of life on Earth. Methane (CH4),ammonia (NH3), hydrogen (H2) in the ratio of 2 : 1 : 2 and water (H2O), the major components of the early Earth’s atmosphere, were taken in a spark chamber which was a closed system.