When standing at sea level how far away is the horizon? Is there a specific measurement?

Answer 1

This is a simple bit of trigonometry.

Think of a right angle triangle. The right angle is at the distant point on the horizon. The two sides are that point to earth centre (earth radius = r) and that point to you, (distance to horiz = d). The hypotenuse is earth radius (r) plus (h) your eye's height above sea level.

Using Pythagoras

d^2 = (h+r)^2 - r^2

= h^2 + r^2 + 2rh - r^2

= h^2 + 2rh

r = 6366 Km
h = say 1.5m

d^2 = 2.25 + 19098000 metres

d^2 = 19098002.25 metres

d = 4370m or 4.37 km

Answer 2

At sea level it's about 3 miles. But from the top of the White Cliffs od Dover you can see France, 21 miles away. Thus the higher above sea level you are, the further away the visible horizon is. It's all down to trigonometry.

Answer 3

1st. In Malaysia, the Penang Bridge have about 13.6 km long across the sea. So, from the starting point before enter, we might see the blur land over there with 13.6km distance. With this, the tower called Komtar are only the object that we can focus with blur sight. If think with our logical thinking dat kind of blur, if the land far only about 1 or 2 or 3km, mean the bridge about +-17km long, sure we cant see whats inside the land.

2nd. The longest bridge with distance about 38km. What intesting here is, when people was in the middle (about 16km) of the bridge, people couldnt see land from both side.

3rd. visibility depends on condition but the answer 1 n 2 doesnt include visibility. That mean in normal visibility.


This factor shown, in clear day we can see the horizon until
+-17km long.

Answer 4

About 3 miles.

Answer 5

Around 3 miles.

Answer 6

About three miles. You can see a ship on the horizon at twelve miles from the bridge of a type 23 frigate (about forty feet) and eighteen from the bridge of a UK aircraft carrier (about eighty feet.)

Answer 7

Bloody good question. But I'm sorry I don't know the answer!
It must be a fair way, because I remember being taught at school about how man began to learn the earth wasn't flat.
And one of the contributing factors to this was: people stood on seashores with nothing but a vast ocean in front of them and began to notice a very, very slight curvature of the horizon.

Thanks for getting my brain ticking, Simon!

Answer 8

I think it's between 2 and 3 miles.

Answer 9

It all depends on the elevation of where you are standing, the surrounding terrain, and how tall you are. But in general, as people here have said, its about 3 miles

Answer 10

20-30 miles, i can see a hill from my back garden which is 6 miles away, but i can see way past that.