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
The Future and Its Enemies The Future and Its Enemies The Future and Its Enemies: The Growing Conflict Over Creativity, Enterprise, and Progress is a 1998 book by Virginia Postrel where she describes the growing conflict in post-Cold War society between "dynamism" – marked by constant change, creativity and exploration in the pursuit of progress – and "stasism", where progress is controlled by careful and cautious planning. Postrel endorses the former, illustrates the differences between the two, and argues that dynamism should be embraced rather than feared. Richard Ebeling wrote a positive review for the Future of Freedom Foundation in May 1999. He remarked, Dr.