The zenith and nadir are terms used in astronomy and geography to describe two points in the sky relative to an observer’s position.
- Zenith: The zenith is the point in the sky directly above an observer. If you imagine a straight line going up from where you’re standing, the zenith is where that line intersects the celestial sphere above you.
- Nadir: The nadir is the point directly opposite the zenith, located directly beneath you. It’s the point straight down, under the Earth’s surface, relative to your position.
In short:
- Zenith = directly overhead.
- Nadir = directly beneath your feet.
These terms are often used to describe the position of celestial objects as they move across the sky, like the sun, moon, or stars.