In still other cases (“3”), rays are scattered back to the ground by dust particles or molecules in the atmosphere, forming the familiar “skyglow” seen over cities. Of these rays, a few (“2″) will be detected by satellites as they pass over the nighttime side of our planet.
Some of the light rays (“1″) are directed up into the sky and travel completely through Earth’s atmosphere. The streetlight emits light in many different directions. The illustration below shows how some of the light we emit on the ground ends up in the lenses of cameras aboard satellites. How Light Scatters Creating Light Pollution and Skyglow A variety of sources available on the web help dark skies enthusiasts around the world to access images from these satellites, and to better understand the light in their own local environments. It comes from light on the ground scattering in the atmosphere and back to our eyes, blotting out the stars.īut some of that light manages to travel all the way through the atmosphere and escape to space. Earth-orbiting satellites intercept some of that light, and their cameras provide valuable evidence of not only where artificial light at night is used in the world, but how its changing. Billions of people around the world routinely experience light pollution in the form of skyglow, the ever-present “haze” of light over cities at night.
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