Structure of the Earth obducted onto the continental crust and preserved as ophiolite sequences. Many rocks now making up Earth's crust formed less than 100 million (1) years ago; however, the oldest known mineral grains are about 4.4 billion (4.4) years old, indicating that Earth has had a solid crust for at least 4.4 billion years. Earth's mantle extends to a depth of 2,890 km, making it the thickest layer of Earth. The mantle is divided into upper and lower mantle. The upper and lower mantle are separated by the transition zone. The lowest part of the mantle next to the core-mantle boundary is
The Core as those found in "The Core". In a poll of hundreds of scientists about bad science fiction films, "The Core" was voted the worst. On February 21, 2010, "The Guardian" ran an article about American professor Sidney Perkowitz's proposals to curb bad science in science fiction movies. In the article, Perkowitz is said to have hated "The Core". "If you violate [the coherent rules of science] you are in trouble. The chances are that the public will pick it up and that is what matters to Hollywood. "The Core" did not make money because people understood the science was so