The Nemesis Theory
[b]The Nemesis Theory: Explanation for Mass Extinction on Earth[/b]Nemesis' existence was proposed by Whitmire and Jackson in Nature in 1984, 308, 713-715, and also by Davis, Hut & Muller in 1984 (Nature 308 : 715-717) to explain an apparent 26-million year cycle in the occurrence of mass extinctions on Earth.