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
What Do You See? What Do You See? "What Do You See?" (就在这里 in Mandarin) is a song by Singaporean band Electrico. It was commissioned as the official theme song for the 2009 National Day Parade. The song is one of the few National Day Parade theme songs that does not mention the word ""Singapore"" in its lyrics. Its lyrics were cited by Prime Minister Lee Hsien Loong in his 2018 National Day Message. Directed by Bertrand Lee, the music video opens with a bokeh and later sharpens to reveal band member David Tan. The camera then traces him around the downtown core of