First of all, a theory is exactly that – a theory. One step up from a hypothesis! Belief in theory is not the scientific way … it is the way of the dreamer, one who builds castles in the sky.
Now, without dreamers to concoct good theories, we would not have science as we know it today – but theories must pass the proverbial litmus test to join the ranks of the believable. Has Primordial Soup Theory passed such a litmus test?
Primordial Soup Theory proposes that life began in a warm pond or ocean as a result of a mix of atmospheric chemicals along with some form of energy to make amino acids – the building blocks of proteins from which all species of life then evolved. This process is presumed to have happened at least 3.8 billion years ago.
In this theory, amino acids came from a simple molecule which formed in the atmosphere. This molecule was then energized by a combination of lightning and rain from the atmosphere creating an “organic soup.”
In 1950, Chemist Stanley Miller and physicist Harold Urey experimented to test this theory by mixing gases thought to be present on a primitive earth: hydrogen (H2), ammonia (NH3), methane (CH4), water (H2O) – no oxygen.
Then, in much like a Dr. Frankenstein experiment, they electrically sparked the gas mixture to simulate lightning. The results culminated in amino acids; it was later discovered that other energies could also be used to excite gases and to produce all 20 amino acids. These catalytic energies include ultraviolet light and heat energy.
There were problems with the theory including:
1. Amino acids are building blocks of protein, not the assembled structure. Amino acids would yet have to become protein.
2. Earth’s early atmosphere would have contained different gases than those used by Miller and Urey; for instance, no ammonia or methane would have been present.
3. The Second Law of Thermodynamics got in the way – according to this law of physics, systems tend to become less organized over time – which would mean that amino acids would not spontaneously form protein (which would signify a progressive organization).
In another experiment (by Sidney Fox), heated amino acids gave off water as steam and formed peptide chains. These were proteinoids (protein-like molecules) though, not real proteins. Some theories propose that proteinoids were a precursor to the first living cells.
The fact that Primordial Soup Theory has not yet been proven, does not invalidate it as a potential scientific fact … perhaps we need to keep experimenting and testing the theory. Do I believe in Primordial Soup Theory? I believe in it as a worthy theory; worthy of further speculation and experimentation. It has not however been proven yet beyond a doubt.
The fact that this theory has lead to discovery (and greater understanding) regarding the formation of amino acids and of protein-like molecules formed inorganically from amino acids certainly indicates its usefulness – as a springboard for discovery! In as much as that, I certainly do believe in Primordial Soup Theory, but as yet, we are only stirring the surface of it.