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
1066 The Battle for Middle Earth and Hastings, the little village was, according to the book, "laid to waste" in 1066. In the series, it serves as the hometown for the fictional peasant soldiers Tofi, Leofric, and Ordgar, whose names are actual Anglo-Saxon names from the period. Viewers may assume that the programme's title refers to "The Lord of the Rings" books, but Hardy chose "Middle Earth" because Anglo-Saxons frequently used the term to describe their world. He notes that J. R. R. Tolkien, an Oxford professor of Anglo-Saxon, used it, along with other Anglo-Saxon words, for the same reasons. 1066 The Battle for Middle Earth