One of America's largest meteor craters is around 100 million years younger than scientists thought, which means the ancient impact coincided with — and potentially contributed to — one of the biggest global extinction events in Earth's history, according to a new study.The underground impact structure, known as Ames crater, is located in northern Oklahoma and is named after a small town that sits above the submerged crater. At around 10 miles (16 kilometers) wide, it is the fourth-largest impact structure in the U.S.Ames crater was created when an Eiffel Tower-size space rock slammed into our planet at more than 70,000 mph (110,000 km/h). At the time, the region was covered in a shallow oce...