What is nadir in astronomy?

Nadir: Nadir is a term used in astronomy for the point in the heavens exactly opposite to the zenith, the zenith and nadir being the two poles of the horizon. That is, the zenith is directly overhead, the nadir directly underfoot. read more

Nadir is directly down. Nadir is a great term outside of astronomy. For example, in the stock market. If you think of the high point as the zenith, you can think of the low point as the nadir point. read more

Study Astronomy Online at Swinburne University All material is © Swinburne University of Technology except where indicated. NADIR: The point directly below in the direction of the center of the earth. read more

Nadir, a term used in astronomy for the point in the heavens exactly opposite to the zenith, the zenith and nadir being the two poles of the horizon. That is, the zenith is directly overhead, the nadir directly underfoot. read more

The point 180° opposite the zenith, directly underfoot, is the nadir. Astronomical zenith is defined by gravity; i.e., by sighting up a plumb line. If the line were not deflected by such local irregularities in the Earth’s mass as mountains, it would point to the geographic zenith. read more

In astronomy, “nadir” is usually the direction of the local net gravitational force on a stationary object on the surface of a planet. It’s “down” if you define “down” as the direction of the local net gravitational force (including effects planetary rotation), which is generally true in most surface applications. read more

Specifically, in astronomy, geophysics and related sciences (e.g., meteorology), the nadir at a given point is the local vertical direction pointing in the direction of the force of gravity at that location. The direction opposite of the nadir is the zenith. read more