Ship Wakes and Round Earth
July 27, 2009
Turbulent ship wakes stream aft of vessels and are commonly seen from the stern of a ship. But did you know that these wakes prove that the Earth is round? Look at the left and right edges of the wake. They form two fairly sharp lines that converge in the distance toward the horizon as a result of perspective. But they don’t meet at a point, as they would if the Earth was flat and the line-of-site was infinite. Rather, they’re separated by a small amount of space at the horizon where the observer’s finite line of sight is tangent to the spherical Earth.