Nemesis

nemesis Nemesis Origin of the theory The Nemesis shot was an outgrowth of the discovery of Alvarez et al., that the impact of a large (10 km diameter) comet or asteroid was responsible for the great mass slake that took place 65 million years ago. Studies of the fossil make by Dave Raup and Jack Sepkoski shows that this was not an isolated event, but exclusive of several mass extinguishings that appear to occur on a regular 26 million year cycle. Their original report analyzed marine fossil families, and was published in the levelheaded proceeding of the National Academy of Science USA, vol 81, pages 801-805 (1984).

The original experimental extinction sel ective information of Raup and Sepkoski are replotted in the following figure. The vertical axis vertebra shows the extinction rate. This was receden from the values given by Raup and Sepkoski for the pct family extinctions at each geologic boundary. In order to take into direct the uncertainty in the boundary ages, each data bill was plotted as a Gaussian, wi...If you want to hold a full essay, order it on our website: OrderEssay.net

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