What is Furthest point on the horizon the human eye can see?

Answer 1

How far can we see across the water to the horizon?
Let r = the Earth's radius = 3963 miles
Let h = height of a person in miles
Let d = distance seen to the horizon in miles

The sight line of a person to the horizon would be on a line passing through their eyes and tangent to the Earth at the seen horizon.

Since the radius of any circle is perpendicular to the tangent, the tangent and the radius make the legs of a right triangle. The radius plus the person's height (in miles) are the hypotenuse. We can then use the Pythagorean Theorem. Be careful to convert the person's height into miles.

c2 = a2 + b2

thus ( r + h )2 = d2 + r2

then d2 = ( r + h )2 - r2

d = sqrt ( ( r + h )2 - r2 ) )

Examples: A person with eyes 6 feet off the surface would see approximately 3 miles. From the Bank of China building (1033 ft tall) you would see approximately 39.4 miles.

Remember that mathematics is an approximate representation of the world around us. These numbers must be taken in that light. For instance, these numbers does not take into account atmospheric interference. We are also making the assumption that the Earth is a uniform sphere with a uniform radius of 3963 miles.

Answer 2

I asume that you mean, standing on land looking out over the ocean. The distance to the horizon would depend on the height of your eye above sea level.

If the height of your eye is 6 feet the horizon is about 3.3 statute miles .

Answer 3

Some of the stars are WAY out there, and we can see them. The human eye is a complex device that focuses light images and rods and cones convert the light to nerve impulses. It doesn't really matter how far the light has traveled, only that it's bright enough to make the neural impulse.

Answer 4

When standing at sea level, the distance to the horizon in miles is approximately the square root of one-and-a-half the person's height in feet.

For example, if a person was six feet tall, the horizon would be about three miles away.

The higher above sea level you are, the further away the horizon is.

This is why astronauts can see half the earth's surface when in space and why ships have a 'crows nest' many meters above the deck where a watchman can look out for land.

Answer 5

Visible distance (in nm) = 1.17 x the square root of the height (in feet)

This means, sitting in my sea kayak, the "horizon" is really only about 2 miles away. However, a 50 foot tree on the shore line could be seen 8.5 miles away.

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Answer 6

Everybody sees different in different surroundings. For example, if you're flat against a mountain, you can only see a few inches. If you're at the beach or on a prairie, you can see for miles. Also, some people are nearsighted, some are farsighted, and some have perfect vision.

Answer 7

Human vision is classified as infinite as we do not seem to have any visual range limit. Think about it, we can see the sun, 93 million miles away, and the stars, light years away!

Answer 8

It depends on how well a human's vision is.

Answer 9

About 7 miles at the most.