In a recent unpleasant diary of mine - filled with vapid remarks from mystics who have a special cult like religious relationship with the destroyed reactor at Three Mile Island - the decidedly unpleasant confrontation with mystics was broken up by a serious scientific question.
The question arose when I considered that one of the only things that really worries me about nuclear power is that it will have the long term effect of reducing the radioactivity on earth. I remarked that only 9% of the radioactive potassium-40 isotope that was present during the formation of the earth is still present, the rest having decayed to the Argon 40 which makes up a considerable part of earth's atmosphere. I believe that life - which evolved bathed in radiation - may depend on environmental radioactivity in subtle ways, and I remarked that there is some suggestion that the origins of life bear a trace of this dependence, chirality.
For a description of what chirality is, I suggest that one turn to the fine diary by the Kossack diarist, the chemist Translator, on the subject.
His diary, Pique the Geek: Chirality may be found by clicking on the link.
Just as the origins of the sun's energy was unknown until it was explained by Hans Bethe, political liberal and powerful nuclear power advocate - he died a few years ago at the ripe age of 99 - the real origins of chirality are not understood, and it remains one of the great mysteries in science.
In my unpleasant diary, OMG! Radioactive Co-60 Leaching in Open Soils at Oak Ridge!!!!!! I wrote the following comment:
It is easily shown that if all of the radioactive (3+ / 0-)
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fission product cesium were deliberately dumped in the ocean - potassium and cesium are very close chemical analogues - it would set the geological clock back only a few tens of millions years as far as life in the oceans is concerned. A caveat is that cesium has a higher propensity for being absorbed into minerals than does potassium, and, as a larger atom, less proclivity for living tissue. (The biological half life of cesium in Chernobyl area soils is vastly lower than the radiological half-life.)
The half-life of K-40 - most of which was formed in the series of supernovae from which all elements found on earth that are heavier than lithium originated - is about 1.28 billion years.
The commonly accepted age of the earth is 4.5 billion years.
Thus since the origin of this planet, only about 9% of this potassium remains.
My thesis is that the origin of life is intimately tied to radioactivity. This gut feeling of mine derives from the unexplained origins of chemical asymmetry in all living systems. There is only one of the 4 fundemental forces which is asymmetric, that is the weak nuclear force. C.N. Yang won the Nobel Prize for discovering this. Gravity, electromagnetism and the strong nuclear force are all symmetric.
It has been shown that it is possible - although only on a very small scale - to induce chirality in molecules in the presence of beta decay.
A correspondent wrote:
Really? Fascincating! (1+ / 0-)
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Regarding the induction of chemical chirality in the presence of radioactive decay - wow, that's really cool.
I'd love to read some literature on the subject... (hint, hint.)
So this brief throwaway diary is to provide a link to said literature, because it is always far more pleasant to discuss science than it is to discuss mysticism.
The paper I will cite is Radiation Physics and Chemistry 77 (2008) 961– 967.
From the paper:
- Introduction
Radioracemization can be defined as the degradation processes caused by high-energy radiation on chiral molecules, which leads to a reduction of the optical activity and, for a sufficiently high radiation dose, to the complete racemization, i.e. loss of any optical activity of a given chiral molecular specie. Two parallel processes may be active during the radioracemization: the radiolysis of the chiral molecules into other molecular species without centres of asymmetry or the inversion of chiral centres when a chiral molecule is brought into an excited or transient state followed by its decay into the enantiomeric form (Cataldo et al., 2004). Radioracemization has important implications on the theories of the origin of life because chirality must have preceded the emergence of life and chiral molecules probably were formed in the giant molecular clouds of the interstellar medium or in the solar nebula and then have been included in comets and meteorites and delivered to Earth (Bonner, 1991a, b; Cataldo, 2007a). Experimental evidences of such theories lie in the discovery of chiral prebiotic molecules in meteorites (Pizzarello and Cronin, 2000; Pizzarello, 2004). Thus, if circularly polarized light or other force field may have caused the formation of the chiral excess observed in meteorites, cosmic rays and radionuclide decay may have played against the preservation of such excess just because of the radioracemization phenomena (Cataldo et al., 2005; Cataldo, 2007a).
With these premises it is not surprising that the studies on amino acids radioracemization were started already more than 30 years ago (Bonner et al., 1979, 1985; Bonner and Lemmon, 1981; Bonner, 1984, 1999). More recently, the studies on the radioracemization have been focused also on selected terpenes (Cataldo et al., 2004; Cataldo, 2007b). The results of such studies have been applied to estimate the survival of chiral molecules embedded inside comets and meteorites (Cataldo, 2007a). Certainly, the molecules deeply inside comets and meteorites although they gain an impressive amount of radiation dose in millions of years are not destroyed completely by radiolysis.
The quotation is intended to provide a link to references to parties interested in this subject to read.