The lines leading to chimps, Australopithecine, and us might never have pulled through. The demise of the ruling dinosaurs also probably led to the evolutionary explosion of mammals, adding an additional positive step toward mammalian domination, culminating with the eventual advent of Homo Sapiens. This cometary impact, dating back to 65 million years ago, was studied initially in 1982 by Luis Alvarez and his son Walter, of U.C. Berkeley. They reported on the granddaddy of all anomalies. This anomaly consisted of concentrations of the metal iridium, found as a thin layer restricted to the top of the Cretaceous.
Iridium is very rare in the Earth's crust, but is more common in meteorites and comets.
This accumulation of iridium at the Cretaceous-Tertiary boundary appears to have occurred instantaneously and arrived all in one day aboard a giant meteor or asteroid. This Cretaceous meteor impact event is now quite accepted by the scientific community, with the crater thought to be located in the Caribbean close to the Yucatan Peninsula. Logically, the expected cometary approach, predicted for 2028, should be taken seriously and prepared for well in advance of the event.