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 through the crust underwater, leaving them safe on the ocean floor, but power and communications are offline. They believe themselves lost underwater but use the remaining power to activate a weak sonar beacon. The beacon attracts a nearby whale pod, and Finch is able to trace their whale songs to locate the "Virgil". A week after the mission, Finch unleashes the full details of the mission (including those lost) and of DESTINI to the public via the Internet. "The Core" had out-to-sea scenes, starring , with full support of the US Navy. The film garnered mixed reviews. The film received