Courtesy NASA Asteroidal assassins People have been worrying about cosmic collisions for a long time, but the field only gained scientific legitimacy in the 1980s when the extinction of the dinosaurs was pinned on a single strike of a comet or asteroid. Now we have the assertion , based on a computer simulation by Australian engineer Michael Paine , that during the last 10,000 years, Earth was hit about 350 times by asteroids as large as the rock that wasted 2,000 square kilometers of Siberian forest in 1908. According to the simulation, during the next 10,000 years, cosmic junk could kill 13 million people, and perhaps cause wars, famines and general-purpose chaos. Although the assertion was not published in a refereed journal, the alarming news was discussed at a national scientific meeting in February. A 10-kilometer asteroid strikes north of the Yucatan Peninsula, causes a global firestorm, then a cold snap and finally a global warming that extinguishes the dinosaurs.
Mammals move to center stage.
Some eventually make important discoveries like bingo, the Edsel , and the painful effects of asteroids. Because the stony object exploded in the atmosphere, there's no crater. In equal parts bogus and frightening, Velikovsky casts the entire field of impact studies into disrepute. The goal is to get a statistical picture of orbiting rocks anywhere in the solar system. Physicist Luis Alvarez and his team blames the dinosaur extinction on the environmental havoc of a collision.