Although Italian by birth, maritime explorer Christopher Columbus sailed across the Atlantic Ocean and discovered the Americas under the Spanish emperorâs name. During his first voyage, he led three Spanish galleons, the NiÃ±a, Pinta, and the Santa Maria.
Instead of the general notion that a void is a region of space with a low cosmic mean density; a hole in the distribution of galaxies, it defines voids to be regions in which matter is escaping; which corresponds to the Dark Energy equation of state, w.
Used in geology, hydrogeology, soil science, and building science, the porosity of a porous medium (such as rock or sediment) describes the fraction of void space in the material, where the void may contain, for example, air or water. It is defined by the ratio :