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
And What Will We Do Tomorrow? And What Will We Do Tomorrow? "And What Will We Do Tomorrow" is a short story by Orson Scott Card. It first appeared in his short story collection "Capitol" and then later in "The Worthing Saga". This story is about Mother the empress of Capitol. In it she wakes up from suspended animation for her one waking day every five years and meets with all of her ministers. All of them try lying to her except for the minister of colonization who doesn’t know anything about what is going on in his department. She sends him away and asks to