The pictures sent back to us from Weather Satellites are simply photographs taken from outer space. We get visible images during the daylight when the earth reflects sunlight back to outer space. Visible pictures show the amount of light reflected back to outer space. Thick water rich clouds, such as stratus (common along the North Coast during Summer months), show up as bright white on visible pictures. Snow pack over the Sierra Nevada during the Winter is another good reflector of sunlight. During the night, visible pictures are completely black as there is very little or no visible light to reflect!