There appears to be a correlation between the rise and fall of civilizations with the rise and fall of radiation from the sun. The graph shows a long-term envelope of sunspot activity derived from the center graph of Carbon 14. More carbon 14 is absorbed in the growth rings of tress during the sunspot minima. Sunspot minima also correlates with mini-ice ages and a winter severity index based on a mean for Paris and London - for the period shown. The Maya disappeared during a sunspot minimum (see also HERE + HERE + HERE)
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