Mantle (geology) Mantle (geology) The mantle is a layer inside a planetary body bounded below by a core and above by a crust. Mantles are made of rock or ices, and are generally the largest and most massive layer of the planetary body. Mantles are characteristic of planetary bodies that have undergone differentiation by density. All terrestrial planets (including Earth), a number of asteroids, and some planetary moons have mantles. The Earth's mantle is a layer of silicate rock between the crust and the outer core. Its mass of 4.01 × 10 kg is 67% the mass of the Earth. It has
Innovation and Its Discontents Innovation and Its Discontents Innovation and Its Discontents: How Our Broken Patent System Is Endangering Innovation and Progress, and What To Do About It is a book () by Adam B. Jaffe and Josh Lerner. Princeton University Press published the book in 2004. The authors of the book outline changes made to the patent system in the United States in the late 1980s and early 1990s which they say has led to a situation in which patents have become extremely powerful economic weapons, and are being issued irresponsibly and at an unreasonable rate. The end result, the authors claim, is