Later, as the months wear on, a series of additional messages arrive from Gerry -- always delivered in the most remarkable and surprising of ways. With each new message comes a new adventure, and each letter signs off in the same familiar way: P.S. I love you..
For a person standing at sea level, however, the horizon is only about 3 miles away. Lets do the calculations. The figure below shows an observer whose eyes are a distance E above sea level. A straight line drawn from the observers eyes tangent to the seas surface touches it at the distance d1, which is the distance to the horizon. If R is the radius of the earth, then, to first order in E/R, it is easy to show that.
The following diagram shows you how the distance to the horizon can change depending on the height of the observer : So the distance to the horizon depends on the height of your eyes above the water. If your eyes are 8 inches (20 cm) above the water, the distance of the horizon is about 1 mile (1.6 km) away. A rough formula for calculating the distance to the horizon is: where height above surface is in feet and distance to horizon is in miles. If you are 6 feet tall and standing right at the water's edge, then your eyes are about 5.5 feet above the surface. The distance to the horizon is: In metric, the equivalent is: