This program explores Earth's age, uncovers fossils and traces evolution through the geological time periods. It also examines continental drift, studies cockroaches, early communication, and the role of mass extinctions throughout history.
"Asteroids come in all shapes and sizes--and hit our planet in them, too. But what happens if a catastrophically large one approaches earth? By looking on the ground at historical asteroid craters and present-day falls, and up into space for the big ones yet to come, a wide variety of scientists are trying to figure out how to track asteroids--and how to avoid devastating impacts in the future."--.
Twelve-year-old twins Nick and Eryn investigate why their mother and new stepfather are keeping secrets, why they are forbidden to meet their stepsiblings, and, most important, why their lives are in danger.
When Dominique, Eric, Josephine, and Ajay return to the Smithsonian they see that modern animals are extinct and dinosaurs have been brought back to life, so they time travel to the 1876 Philadelphia Exhibition to stop this wicked plot.
