The evidence for the origin of life from inanimate matter was provided through an experiment, conducted in 1953, by Stanley L. Miller and Harold C. Urey.
- In an experiment, they assembled an atmosphere containing molecules like ammonia, methane and hydrogen sulphide, but no oxygen, over water. This was similar to the atmosphere that thought to exist in early heart
- . This was maintained at a temperature just below 100°C and sparks were passed through the mixture of gases to simulate lightning.
- At the end of a week, 15% of the carbon from methane was converted to simple compounds of carbon including amino acids which make up protein molecules and support life in basic form. From this, it was inferred that life arose afresh on earth.