One fragment, known as Nucleus G, struck with the force of about six million megatons—seventy-five times more than all the nuclear weaponry in existence. Nucleus G was only about the size of a small mountain, but it created wounds in the Jovian surface the size of Earth. It was the final blow for critics of the Alvarez theory.
Luis Alvarez never knew of the discovery of the Chicxulub crater or of the Shoemaker-Levy comet, as he died in 1988. Shoemaker also died early. On the third anniversary of the Shoemaker-Levy impact, he and his wife were in the Australian outback, where they went every year to search for impact sites. On a dirt track in the Tanami Desert—normally one of the emptiest places on Earth—they came over a slight rise just as another vehicle was approaching. Shoemaker was killed instantly, his wife injured. Part of his ashes were sent to the Moon aboard the Lunar Prospector spacecraft. The rest were scattered around Meteor Crater.
Anderson and Witzke no longer had the crater that killed the dinosaurs, "but we still had the largest and most perfectly preserved impact crater in the mainland United States," Anderson said. (A little verbal dexterity is required to keep Manson's superlative status. Other craters are larger—notably, Chesapeake Bay, which was recognized as an impact site in 1994—but they are either offshore or deformed.)