Newton knew what he had done. He was no accidental writer. A parabola, of course, is a curve that keeps on going – and that meant that at the end of a very long and very dense book, he lifted off again from the hard ground of daily reality and said, in effect, look: All this math and all these physical ideas govern everything we can see, out to and past the point where we can’t see anymore.
Most important, he did so with implacable rigor, a demonstration that, he argued, should leave no room for dissent. He wrote “The theory that corresponds exactly to so nonuniform a motion through the greatest part of the heavens, and that observes the same laws as the theory of the planets and that agrees exactly with exact astronomical observations cannot fail to be true.” (Italics added).
Todd Suomela on 07 Apr 09Of the twenty amino acids used in proteins, ten were formed in Miller's atmospheric discharge experiments. The two other major proposed sources Of prebiotic amino acid synthesis include formation in hydrothermal vents and delivery to Earth via meteorites. We combine observational and experimental data Of amino acid frequencies formed by these diverse mechanisms and show that, regardless Of the source, these ten early amino acids can be ranked in order Of decreasing abundance in prebiotic contexts. This order can be predicted by thermodynamics. The relative abundances Of the early amino acids were most likely reflected in the composition Of the first proteins at the time the genetic code originated. The remaining amino acids were incorporated into proteins after pathways for their biochemical synthesis evolved. This is consistent with theories Of the evolution Of the genetic code by stepwise addition Of new amino acids. These are hints that key aspects Of early biochemistry may be universal.
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