The discovery by Alvarez and Alvarez (1980) of the Cretaceous-Paleocene boundary (~66 million years-ago) asteroid impact, eliminating approximately 80 percent of all species, has among other released enough dust and debris to cloud large parts of planet, enhancing the mass extinction of some 80 percent of species of animals. When Turco et al. (1983) and Carl Sagan (1983) warned the[Read More...]
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