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
Faith in the Earth all. The Earth represents our one and only window of opportunity, at the same time as it symbolizes all of our unknown higher potentials. Neither spaceman nor God will come to save us. But this is not a bleak dystopian materialism, because just as our simian ancestors couldn't realize that the development of their vocal cords (something they already had at least in rudimentary form) would open up those new dimensions of reality that we call language, civilization, and culture, just so we ourselves cannot yet get our minds around what we might be able to do already in rudimentary