Horizon - Netflix

Horizon tells amazing science stories, unravels mysteries and reveals worlds you've never seen before.

Horizon - Netflix

Type: Documentary

Languages: English

Status: Running

Runtime: 60 minutes

Premier: 1964-02-05

Horizon - Horizon - Netflix

The horizon or skyline is the apparent line that separates earth from sky, the line that divides all visible directions into two categories: those that intersect the Earth's surface, and those that do not. At many locations, the true horizon is obscured by trees, buildings, mountains, etc., and the resulting intersection of earth and sky is called the visible horizon. When looking at a sea from a shore, the part of the sea closest to the horizon is called the offing. The word horizon derives from the Greek “ὁρίζων κύκλος” horizōn kyklos, “separating circle”, from the verb ὁρίζω horizō, “to divide”, “to separate”, and that from “ὅρος” (oros), “boundary, landmark”.

Horizon - Objects above the horizon - Netflix

which comes to about 35 kilometres. It is similarly possible to calculate how much of a distant object is visible above the horizon. Suppose an observer's eye is 10 metres above sea level, and he is watching a ship that is 20 km away. His horizon is:

which comes to almost exactly six metres. The observer can therefore see that part of the ship that is more than six metres above the level of the water. The part of the ship that is below this height is hidden from him by the curvature of the Earth. In this situation, the ship is said to be hull-down.

kilometres from him, which comes to about 11.3 kilometres away. The ship is a further 8.7 km away. The height of a point on the ship that is just visible to the observer is given by:

D        ≈        3.57        (                              2                          +                              70                          )              {\displaystyle D\approx 3.57({\sqrt {2}}+{\sqrt {70}})}  

To compute the greatest distance at which an observer can see the top of an object above the horizon, compute the distance to the horizon for a hypothetical observer on top of that object, and add it to the real observer's distance to the horizon. For example, for an observer with a height of 1.70 m standing on the ground, the horizon is 4.65 km away. For a tower with a height of 100 m, the horizon distance is 35.7 km. Thus an observer on a beach can see the top of the tower as long as it is not more than 40.35 km away. Conversely, if an observer on a boat (h = 1.7 m) can just see the tops of trees on a nearby shore (h = 10 m), the trees are probably about 16 km away. Referring to the figure at the right, the top of the lighthouse will be visible to a lookout in a crow's nest at the top of a mast of the boat if

Horizon - References - Netflix