What caused the rapid extinction, some 12,900 years ago, of large mammals such as woolly mammoths, saber-toothed cats, and giant ground sloths that roamed North America? The NOVA program explored the leading theories, including the possibility that a comet broke apart in the atmosphere and smashed into the continent in multiple pieces, triggering explosions, forest fires and other devastating effects that led to the demise of up to 35 species of large mammals. The judges called the program, which used striking computer animations of the animals in question, a balanced exploration of a controversial theory.

“The piece exhibited great writing, with dramatic tension between competing views,” said Janet Raloff of Science News. Kathy Sawyer, a freelance science writer formerly with The Washington Post, said the program “dramatizes the rigors of the scientific method in such compelling areas as the search for a specific layer of ice from 12,900 years ago, the discovery of extraterrestrial nano-diamonds that brings one scientist to tears, and clues hidden in sloth poop.” Hamilton said there were no guarantees when his team decided to follow a scientific expedition in Greenland where the outcome was very uncertain. In the end, he said, “not only were the results really fascinating, it allowed us to show real science in action—from strenuous field work to the emotional thrill of those rare moments of discovery.”