Asteroid as powerful as 10 billion WWII atomic bombs may have wiped out the dinosaurs
(CNN) -- Scientists have discovered evidence that the impact of an asteroid as powerful as 10 billion World War II-era atomic bombs caused the extinction of the dinosaurs. The 7.5-mile (12-km) wide asteroid struck the Earth 66 million years ago and caused 75% of life on the planet to become extinct, according to research led by the University of Texas and published in the PNAS journal. It is thought the event triggered wildfires over 900 miles away, as well as sparking a devastating tsunami.