Core–mantle boundary Core–mantle boundary The core–mantle boundary (CMB in the parlance of solid earth geophysicists) of the Earth lies between the planet's silicate mantle and its liquid iron-nickel outer core. This boundary is located at approximately 2891 km (1796 mi) depth beneath the Earth's surface. The boundary is observed via the discontinuity in seismic wave velocities at that depth due to the differences between the acoustic impedances of the solid mantle and the molten outer core. P-wave velocities are much slower in the outer core than in the deep mantle while S-waves do not exist at all in the liquid portion of
How the Snake Lost Its Legs many of the, "nuts and bolts of evolution, deeper than just natural selection," are on display in the book, revealing, "precisely what genetic/physiological mechanisms are being selected for." The molecular biologist Arnaud Martin observes that, "As children, we have all wondered about 'the How and the Why' of animal features, and if you are reading this it is in fact quite possible that a similar inquisitiveness still burns within you. The tone of "How the Snake Lost its Legs" finds its roots in the famous "Just So Stories" of Joseph Rudyard Kipling by tickling this curiosity with the formulaic "How