How far can you see to the horizon?
The circle represents a cross-section of the Earth.
Imagine you are in a balloon at
shows the furthest point, , on the Earth's surface that you could see.Code:B o |\ | \ h| \ | \ | \ * * * \ * | *\ T * | o * R| * * | *R * | * * * o * * O * * * * * * * * * *
The balloon is at miles above the Earth.
The center of the Earth is ; the radius is:
The angle at is 90°.
Using Pythagorus on
Therefore: . , the distance from the balloon to the horizon
. . is given by: . miles
where: . = height of balloon, = radius of the Earth (both in miles).