Hiding Behind the Flat Earth Water Horizon
Click the thumbnails in this Interactive Lesson to change photos to see if you can detect a difference in the photos as the camera position and/or location changes.
The
Breakwater Pier photos were all taken in a total period of about 10 minutes.
The
Power Plant Smokestack photos were both taken in a total period of about 15 minutes.
And the
Chicago Skyline photos were taken over a span of several years.
If you live near a large body of water, you can take photos of structures or even trees along the shore. Photos can be taken from a boat or from the shore while looking at another section of shore along the same coast.
If the Earth is flat then no matter what your elevation above the water surface is, you should always be able to see the entire distant shore completely from the water surface to the top of the object that you are looking at.
However, if the Earth is a sphere, then the further from the object you are the object’s base will be increasingly hidden behind your water horizon.
It is important to understand that if the Earth is spherical, looking at objects that are 5 or
more miles away and with the observer’s eyes less than 8 feet above the water surface will offer the best observable result.
If you are about 5 feet 8 inches tall and are standing at the same level as the water surface and if the Earth is a sphere, then things will begin to progressively be hidden by your water horizon starting at about 3 miles away as your distance
from the object increases. You can use
Lesson 10 to determine your water horizon and how much of an object should be hidden by the water horizon from a given distance when your eyes are at a given height.
When calculating distant objects like the
Chicago Skyline, make sure to add the land surface height to the height of the tallest towers in the skyline. St Joseph, MI is about 120 feet above the water surface of Lake Michigan.
To make certain that your conclusions are accurate, including the land surface height is a key factor.