Did an Asteroid Really Kill the Dinosaurs?
Join a class as they visit a museum to see the dinosaurs they have displayed. As part of the discussion, students learn about meteorites, asteroids, and comets and how they have affected Earth. They ask, "Did an Asteroid Really Kill the Dinosaurs?"
Earth is continually struck by space fragments of varying sizes. Classic examples of impact events are illustrated, including those in Arizona, Siberia, Alabama, New York, and the 2013 explosion over Chelyabinsk, Russia. Viewers also learn about an ancient impact crater in Wisconsin and how craters tell scientists about the early days of the Solar System. In short, evidence of impacts can be found on every planetary system and even explain how Earth's Moon may have been formed.
Despite showing interest in things that have crashed into Earth from space, the students really want the guide to tell them about the dinosaurs. A brief introduction about the reign of the dinosaurs is given along with visuals to illustrate that positions of the continents and oceans of Earth were different compared to the planet we know today. The "Age of the Dinosaurs," or Mesozoic, is comprised of three geologic periods called the Triassic, Jurassic, and Cretaceous Periods.
Walter and Luis Alvarez discovered a thin layer of clay between sediments deposited at the end of the Cretaceous and the start of the Paleogene, the first period of the Cenozoic. The Alvarezes discovered that the clay layer was enriched with Iridium, an element found more abundantly in space rocks than in those on the Earth's surface. This finding and a worldwide distribution of the clay suggested an asteroid impact.
An asteroid impact prompted scientists to look for other kinds of proof from shocked quartz, soot, and an impact crater. Eventually a crater (Chixulub) near the Yucatan Peninsula of Mexico was discovered that appears to be a smoking gun for a mass extinction event on Earth. Scientists today still are studying this impact event and wonder what would happen today if the Earth were struck. Today, scientists understand that an asteroid may be a great resource for man, but an impact would be catastrophic for our planet.
The program concludes with the question, "Did an Asteroid Really Kill the Dinosaurs?," forcing the students to conclude that it looks that way, but science is a process, and more information needs to be found to support this answer. The class moves on with a new question: "What kind of dinosaur would you be?"