2006-09-22 07:46:04 · 9 answers · asked by eamane_t999 1 in Science & Mathematics ➔ Geography
As far as the eye can see :P
2006-09-22 10:20:48 · answer #1 · answered by ? 2 · 0⤊ 0⤋
The horizon (from Greek orizein, to limit) is the line that separates earth from sky. More precisely, it is the line that divides all of the directions you can possibly look into, into two categories: those which intersect the Earth, and those which do not. At many locations, the true horizon is obscured by trees, buildings, mountains and so forth. The resulting intersection of earth and sky is instead known as the visible horizon.
Distance to the horizon
The distance d in kilometers to the true horizon on earth is approximately
where h is the height in meters of the eyes. Examples:
Standing on the ground with h = 1.70 m (eye-level height), the horizon is at a distance of 4.7 km.
Standing on a hill or tower of 100 m height, the horizon is at a distance of 36 km.
To compute to what distance the tip of a tower, the mast of a ship or a hill is above the horizon, add the horizon distance for that height. For example, standing on the ground with h = 1.70 m, one can see, weather permitting, the tip of a tower of 100 m height at a distance of 4.7+36 ≈ 41 km.
In the Imperial version of the formula, 13 is replaced by 1.5, h is in feet and d is in miles. Examples:
Standing on the ground with h = 5 ft 7 in (5.583 ft), the horizon is at a distance of 2.89 miles.
Standing on a hill or tower of 100 ft height, the horizon is at a distance of 12.25 miles.
The metric formula is reasonable (and the Imperial one is actually quite precise) when h is much smaller than the radius of the Earth (6371 km). The exact formula for distance from the viewpoint to the horizon, applicable even for satellites, is
where R is the radius of the Earth (note: both R and h in this equation are in kilometers).
The above formula for d is for the straight line of sight distance to the top of the object of view. A different relationship involves the arc length distance s along the curved surface of the Earth to the bottom of object:
The distances d and s are nearly the same when the height of the object is negligible compared to the radius (that is, h<
As a final note, the actual visual horizon is slightly further away than the calculated visual horizon, due to the slight refraction of light rays due to the atmospheric density gradient. This effect is typically neglected.
2006-09-22 07:55:37 · answer #2 · answered by mysticideas 6 · 1⤊ 0⤋
If you are at a ship at sea, you can see 4 kilometers, till the earth makes a bow...
you can suddenly see a sail at the horizon and the distance is about 4 km, or 3 miles
2006-09-22 07:55:41 · answer #3 · answered by frenzie-ann 4 · 0⤊ 0⤋
Ont the ocean, the only true horizon, 13 miles. On land anywhere from 100 yards to 13 miles.
2006-09-22 07:54:48 · answer #4 · answered by Anonymous · 0⤊ 0⤋
The "horizon" is merely what you can't see due to the curve of the Earth. You can measure it, but I don't know how. But you can't "get to the Horizon", because you'll always have a new horizon.
2006-09-22 16:41:31 · answer #5 · answered by Anonymous · 0⤊ 0⤋
I read somewhere that it is about 3 miles distant if you are standing on a flat surface on the ground. I would suppose that is you are in an airplane, it would be a good deal farther.
2006-09-22 07:54:17 · answer #6 · answered by Bibi B 2 · 0⤊ 0⤋
It depends on your altitude and if its clear or cloudy. At sea level on a clear day you can see approx. 3 miles. At an altitude of 90 feet you can see about 30 miles.
2006-09-22 07:52:31 · answer #7 · answered by Anonymous · 1⤊ 0⤋
I was always told it was about 15 miles
2006-09-22 07:53:42 · answer #8 · answered by The Cheminator 5 · 0⤊ 0⤋
Just past the end of your nose.
2006-09-22 08:16:01 · answer #9 · answered by Anonymous · 0⤊ 0⤋