Difference between revisions of "Nadir"

Revision as of 21:38, October 13, 2007

The nadir is the point on Earth directly beneath a satellite, the opposite of zenith. Compare with subsatellite point. ^[1]

The point of the celestial sphere that is directly opposite the zenith and vertically downward from the observer.

Etymology: Middle English, from Middle French, from Arabic naḍhīr opposite Date: 15th century. ^[2]

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 [[Image:CenitNadir.gif|right|250px]]
-Point on [[Earth]] directly beneath a [[satellite]], the opposite of [[zenith]]. Compare with [[subsatellite point]]. <ref> [http://earthobservatory.nasa.gov/Library/glossary.php3?mode=all NASA Earth Observatory glossary] </ref>
+The '''nadir''' is the point on [[Earth]] directly beneath a [[satellite]], the opposite of [[zenith]]. Compare with [[subsatellite point]]. <ref> [http://earthobservatory.nasa.gov/Library/glossary.php3?mode=all NASA Earth Observatory glossary] </ref>
 ''The point of the celestial sphere that is directly opposite the zenith and vertically downward from the observer.''