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) similar interface. Computers in close proximity may be connected by wires directly between their interface cards. When connected at a distance, each endpoint would be fitted with a modem to convert analog telecommunications signals into a digital data stream. When the connection uses a telecommunications provider, the connection is called a dedicated, leased, or private line. The ARPANET used leased lines to provide point-to-point data links between its packet-switching nodes, which were called Interface Message Processors. In modern computer networking, the term point-to-point telecommunications means a wireless data link between two fixed points. The telecommunications signal is typically bi-directional and