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Galactic rays and evolution - Life, the mind, civilisation, economics, financial markets
I'm not sure when the first papers were published regarding the influence of galactic rays on terrestrial processes, but this theme seems to have developed following the suggestion of a correlation between galactic rays and cloud cover by ??? in the ?1950's?. Work by ?Fris-? and "Svendsen? supported the concept of a climate-galactic ray link, presumably due to the influence of galactic rays on cloud cover, but perhaps other mechanisms might also explain the galactic ray - climate link.
[Harrison, Prospero 1974] discussed early efforts [Uffen,RJ, Nature, v198, p143 1963] to tie discontinuities in evolutionary records to cosmic radiation exposures during periods of low geomagnetic field strength. However, this explanation was apparently later rejected because it was thought that the changes in cosmic radiation would be insufficient to account for the discontinuities. Direct influence of magnetic fields on biology was one suggestion at the time, but Harrison & Prospero focussed on the gomagnetic influence on climate. They reffered to [Roberts and Olson - I don't have their reference on hand], who suggested that cosmic rays affected cirrus cloud cover and hence climate.
A key paper by Nir Shaviv and Jan Veizer pointed out the galactic ray - climate link over the Phanerozoic era. Although the original paper was based on relatively few meteorite samples, many critiques of the paper have been address (although one can expect uncertainty as ideas evolve) and the number of publications on this theme has rapidly grown. At this point in time it appears that galactic rays are one of the key climate drivers on all time scales, and the field is quite exciting.
Part of the galactic ray variability is due to smooth astronomical trends, of which a key long-term trend seems to be the bobbing of the solar system above and below the plane of the Milky Way, exposing Earth to more or less galactic rays, and possibly extra-galactic rays (from beyond the Milky Way) on the "North side of the Milky Way".
Another part of the variability of galactic rays is due to the chaotic variability of solar activity, which shields the Earth somewhat, and the probable variability of the sources of galactic rays.
Galactic rays can easily damage cells and DNA, and apparently can even kill lifeforms. Medvedev & Melott estimate that the "bobboing" mechanism could result in galactic rays varying by a factor of 100, and that the 69 My periodicity to the boobing would explain the frequency of mass extinctions and biological diversity as seen in the geological record over the Phanerozoic era. Wickson has also presented material on the potential influence of galactic rays on the evolution of life.
Howell has proposed a model for the influence of solar activity (and other astronomical processes such as Milankovic cycles and galactic rays) on the rise and fall of civilisations.
It is also suggested that galactic rays may influence the evolution of the human mind (beyond the trends and events in history, which creat tremendous evolutionary pressure!), economics, and financial markets. However, there has been time to elaborate on these last themes.
Given that this webpage is very incomplete and that it may take until Jun07 to take the time to really build it up, at least the [background - concept - framework] document on civilisations will provide early illustrations and comments. Hopefully permission will be granted to post key papers on this website, as some of this material is difficult to obtain.