Snell’s Window

How the species under water see the world above? The entire horizon is visible to them through a window, a disc, called Snell’s window named Dutch mathematician Willebrord Snellius. Anything outside this window is not visible. In fact the area outside this window looks dark. The diameter of disc varies with the depth at which the viewer is located below water. As the depth of eye increases, the disc gets bigger in size. All this depends upon the strange properties of the light which illuminates this world and which enters our eyes which act as a camera. We know now that …

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