Dating fossils top commentators closed
Geochemical studies have found that the chemical properties of the Earth's mantle would have been the same in the past as they are today.found that the chemical properties of the Earth's interior have been essentially constant over Earth's history, leading to the conclusion that "Life may have found its origins in other environments or by other mechanisms." So drastic is the evidence against pre-biotic synthesis of life's building blocks that in 1990 the Space Studies Board of the National Research Council recommended that origin of life investigators undertake a "reexamination of biological monomer synthesis under primitive Earthlike environments, as revealed in current models of the early Earth." Because of these difficulties, some leading theorists have abandoned the Miller-Urey experiment and the "primordial soup" theory it is claimed to support.
(Reducing gasses are those which tend to donate electrons during chemical reactions.) UC Santa Cruz origin-of-life theorist David Deamer explains this in the journal This optimistic picture began to change in the late 1970s, when it became increasingly clear that the early atmosphere was probably volcanic in origin and composition, composed largely of carbon dioxide and nitrogen rather than the mixture of reducing gases assumed by the Miller-Urey model.After running the experiments and letting the chemical products sit for a period of time, Miller discovered that amino acids -- the building blocks of proteins -- had been produced.For decades, these experiments have been hailed as a demonstration that the "building blocks" of life could have arisen under natural, realistic Earthlike conditions, corroborating the primordial soup hypothesis.Those who harbor doubts about Darwinism need not be terrified by academic bullies who pretend there is no scientific debate to be had.Problem 1: No Viable Mechanism to Generate a Primordial Soup According to conventional thinking among origin of life theorists, life arose via unguided chemical reactions on the early Earth some 3 to 4 billion years ago.From there, they believe Darwinian natural selection took over, favoring those molecules which were better able to make copies.
Eventually, they assume, it became inevitable that these molecules would evolve complex machinery -- like that used in today's genetic code -- to survive and reproduce.
Either way, origin of life theorists must then explain how amino acids or other key organic molecules linked up to form long chains (polymers) like proteins (or RNA).
Chemically speaking, however, the last place you'd want to link amino acids into chains would be a vast water-based environment like the "primordial soup" or underwater near a hydrothermal vent.
As the National Academy of Sciences acknowledges, "Two amino acids do not spontaneously join in water.
Rather, the opposite reaction is thermodynamically favored." In other words, water breaks protein chains back down into amino acids (or other constituents), making it very difficult to produce proteins (or other polymers) in the primordial soup.
In 1953, a graduate student at the University of Chicago named Stanley Miller, along with his faculty advisor Harold Urey, performed experiments hoping to produce the building blocks of life under natural conditions on the early Earth.