Keep in mind that you are not seeing a complete "half" of the earth in this picture. As your distance increases, the effective horizon encompasses more of the s

Keep in mind that you are not seeing a complete "half" of the earth in this picture. As your distance increases, the effective horizon encompasses more of the surface. Only at infinite distance would you see exactly half of a sphere (mathematically speaking). Try taking a picture of your globe closer and closer to the surface and watch as less of the surface is visible in each.