Structure of the Earth the crust, upper mantle, lower mantle, outer core, and inner core. The geologic component layers of Earth are at the following depths below the surface: The layering of Earth has been inferred indirectly using the time of travel of refracted and reflected seismic waves created by earthquakes. The core does not allow shear waves to pass through it, while the speed of travel (seismic velocity) is different in other layers. The changes in seismic velocity between different layers causes refraction owing to Snell's law, like light bending as it passes through a prism. Likewise, reflections are caused by a large
Where Do We Come From? What Are We? Where Are We Going? Boston, acquired it from the Marie Harriman Gallery on 16 April 1936. Where Do We Come From? What Are We? Where Are We Going? Where Do We Come From? What Are We? Where Are We Going? is a painting by French artist Paul Gauguin. Gauguin inscribed the original French title in the upper left corner: D'où Venons Nous / Que Sommes Nous / Où Allons Nous. The inscription the artist wrote on his canvas has no question mark, no dash, and all words are capitalized. In the upper right corner he signed and dated the painting: "P. Gauguin / 1897".