Crust (geology) centers, where partial-melting of the underlying mantle yields basaltic magmas and new ocean crust forms. This "ridge push" is one of the driving forces of plate tectonics, and it is constantly creating new ocean crust. That means that old crust must be destroyed somewhere, so, opposite a spreading center, there is usually a subduction zone: a trench where an ocean plate is being shoved back into the mantle. This constant process of creating new ocean crust and destroying old ocean crust means that the oldest ocean crust on Earth today is only about 200 million years old. In contrast, the
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