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
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.
References: selected articles, mostly related to solar and climate
- CGA Harrison, JM Prospero 16Aug74 "Reversals of the Earth's magnetic field
and climatic changes" Nature v250 August 16 1974, p563-564
- Nir Shaviv, Jan Veizer “Celestial driver of Phanerozoic climate?” GSA
Today, July 2003, pp4-10
- Jan Veizer "Celestial climate driver: A perspective from four billion years of the carbon
cycle" Geoscience Canada, vol32 n1, pp13-28, March 2005
- Edouard Bard, Martin Frank "Climate change and solar variability: What is new under
the sun?" Earth & Planetary Science Letters 248 (2006) pp480-493
- Svensmark and colleagues
- Charles A. Perrya "Evidence for a physical linkage between galactic cosmic
rays and regional climate time series" Advances in Space Research, Article
in Press, Corrected Proof http://tinyurl.com/283ga5
- Mikhail V. Medvedev, Adrian L. Melott "Do extragalactic rays induce cycles
in fossil diversity?" arXiv:astro-ph/0602092v1 Dept of Physics & Astronomy,
Uof Kansas, 4 Feb 2006 13pp
- Steven Wickson "Galactic influences over the last 65 million years"
presentation to a Uof Calgary Astrophysics class, ?2006?
- Steven Wickson "The solar system's motion in the galactic tidal field"
Uof Calgary Astrophysics course 599, Final Report 19Jan06