The asteroid that wiped out the dinosaurs hit Earth near Mexico. Called the Chicxulub impactor, the large rocky object had an estimated width of approximately 6 miles (10 km). It produced a crater that covers an area of about 90 miles (145 km) and the impact is credited not only with the extinction of the dinosaurs, but also for about 75 percent of the total animal species at the time. This mass extinction event took place 66 million years ago and has come to be widely accepted as the end of the Mesozoic era. Now, researchers have discovered where the marauding asteroid originated.
Using computer models, the researchers studied 130,000 asteroid models to conclude that the asteroid orbited the Sun with others in the main asteroid belt before colliding with the Earth.
Researchers at the Texas-based Southwest Research Institute (SwRI) said the impactor likely came from the outer half of the main asteroid belt. The asteroid belt is between Mars and Jupiter.
The researchers also say that the processes that deliver large asteroids from this region to Earth take place at least 10 times longer than previously thought. The SwRI team, including lead researcher Dr. David Nesvorný and colleagues Dr. William Bottke and Dr. Simone Marchi, said several studies had been conducted over the past decade on the mass extinction that ended the dinosaurs’ reign, but each one of them led to new questions.
Two critical questions remained unanswered, said Bottke. One was about the source of the impactor and the other about the frequency of these Earth collision events. So the researchers began by knowing more about the asteroid, which led them to identify the Chicxulub impactor as a carbonaceous chondrite. Many objects around the Earth share similar compositions to the impactor, but are much smaller in size. “We decided to look for where the Chicxulub impactor brothers might be hiding,” said Nesvorný.
The researchers then used NASA’s Pleaides supercomputer. To their surprise, they found that 6-mile-wide asteroids from the outer half of the asteroid belt hit Earth at least 10 times more often than previously encountered.
Study co-author Marchi described the findings as “intriguing.”