Home > Meridian (geography)
:This article is about the geographical concept. For other uses of the word, see Meridian.On the earth, a meridian is a north- south line between the North Pole and the South Pole. It is half of a great circle on the earth's surface. It connects all locations with a given longitude, while the position on the meridian is given by the latitude. It is perpendicular to all circles of latitude.
Considering the meridian that passes through Greenwich, England, as establishing the meaning of zero degrees of longitude, or the Prime Meridian, any other meridian is identified by the angle, referenced to the center of the earth as vertex, between where it and the prime meridian cross the equator. As there are 360 degrees in a circle, the meridian on the opposite side of the earth from Greenwich (which forms the other half of a circle with the one through Greenwich) is 180° longitude, and the others lie between 0° and 180° of West longitude in the Western Hemisphere (west of Greenwich) and between 0° and 180° of East longitude in the Eastern Hemisphere (east of Greenwich). You can see the lines of longitude on most maps.
The term "meridian" comes from the Latin meridies, meaning "midday"; the sun crosses a given meridian midway between the times of sunrise and sunset on that meridian. The same Latin stem gives rise to the terms Ante Meridiem and Post Meridiem.
This article originates from Jason Harris' Astroinfo which comes along with KStarsKStars is a planetarium program that runs under GNU/Linux and other Unix like operating systems. It is part of KDE. It provides an accurate graphical representation of the night sky, from any location on Earth, at any date and time. The display includes u, a Desktop Planetarium for LinuxThis article is about Linux-based operating systems, GNU/Linux, and related topics. See Linux kernel for the kernel itself. See Linux (washing powder) for the Swiss brand of washing powder. Tux, a plump penguin, is the official Linux mascot Linux is the n/ KDEKDE K D esktop E nvironment) is a free desktop environment and development platform built with Trolltech's Qt toolkit. It runs on most Unix and Unix-like systems, such as Linux, BSD and Solaris. There are also ports to Mac OS X using its X11 layer and Mic. See http://edu.kde.org/kstars/index.phtml
