Jean Thompson

Understanding Rarity in the Earth’s CrustThe Earth’s crust is composed predominantly of oxygen, silicon, aluminum, iron, calcium, sodium, potassium, and magnesium. Together, these eight elements account for more than 98% of its mass. By contrast, a small group of elements exists only in trace amounts—sometimes measured in parts per billion (ppb) or even parts per trillion (ppt). Rarity in the crust is determined by average concentration, geological distribution, and stability. Some elements are scarce because they were never abundant in the early solar system; others are rare because they are unstable and decay rapidly.Below are eight of the rarest chemical…

1) Global Positioning System (GPS)Originally developed by the United States Department of Defense during the 1970s for accurate military navigation and missile guidance, GPS achieved full operational status in 1995. Following the removal of selective availability in the year 2000, civilian precision saw a dramatic enhancement. Presently, GPS supports smartphone map applications, flight routing, maritime logistics, ride-sharing services, precise farming, emergency response, and financial system time-stamping. Contemporary economies depend on satellite positioning systems not solely for cartography, but additionally to synchronize electrical grids, banking operations, and telecommunication networks.2) The InternetThe foundations of the Internet trace back to ARPANET, a U.S.…