If you're talking about sky as in sky on this planet, then your answer would be the horizon (the point were the ground meets the sky from any vantage point on the surface). Or you could be talking about the atmosphere, which is the boundary between the earth and space and keeps life alive, and air on earth.
The Horizon line
horizon came first because the horizon runs in a line along the sky, which really is an optical illusion to us, so people in ancient times would think the horizon was a straight line sideways hence the word horizontal
The horizon is where the ground and sky appear to meet at eye level. It is the apparent line that separates the Earth from the sky when viewed from a specific vantage point.
At sea level, the horizon appears to be the point where the sky seems to meet the ocean. This is due to the curvature of the Earth, which creates the illusion of a flat line separating the sky and the sea.
The zenith is the point directly overhead in the sky, while the horizon is the line where the sky appears to meet the Earth. The zenith is the highest point above an observer, while the horizon represents the farthest visible point on the Earth's surface.
The line where the earth meets the sky is called the horizon. It is the apparent line that separates the Earth from the sky when viewed from a specific point.
The horizon. It is a imaginary line where land and sky appear to meet.
A horizon and one can be seen from every point on Earth.
The line where the sky and the earth or sea appear to meet is called the horizon.
The horizon line in a photograph is where the sky meets the land or water. It is often used as a reference point for determining composition and balance in a photo. Placing the horizon line higher can emphasize the sky, while placing it lower can emphasize the foreground.
Horizon Line
The Horizon line
The line where the earth and sky seem to meet is called the horizon. It appears as a visual boundary separating the land from the sky. The horizon is an important reference point for navigation and observing celestial events.
Horizon line. :)
horizon line
Horizon d is the point at which the observer's line of sight meets the horizon, creating a horizontal line separating the sky from the earth. It signifies the boundary where the sky appears to meet the ground or sea in the distance.
where the ground and sky meet