Nadir is employed during remote sensing of the atmosphere, as well as when an astronaut faces the Earth while performing a spacewalk. The term nadir can also be used to represent the lowest point reached by a celestial body during its apparent orbit around a given point of observation. This can be used to describe the location of the Sun, but it is only technically accurate for one latitude at a time and only possible at the low latitudes. The sun is said to be at the nadir at a location when it is at the zenith at the location's antipode
Point-to-point (telecommunications) connection that links only two computers or circuits, as opposed to other network topologies such as buses or crossbar switches which can connect many communications devices. "Point-to-point" is sometimes abbreviated as "P2P". This usage of "P2P" is distinct from "P2P" meaning "peer-to-peer" in the context of file sharing networks. A traditional point-to-point data link is a communications medium with exactly two endpoints and no data or packet formatting. The host computers at either end take full responsibility for formatting the data transmitted between them. The connection between the computer and the communications medium was generally implemented through an RS-232 or