Back to Right Light Proceedings startpage
Syuzo IsobeEnergy Loss of Light Ejected into Space National Astronomical Observatory, Mitaka, Tokyo 181, Japan Abstract Artificial light should be used to make objects visible when people want to see them. However, in many cases light does not illuminate only the objects, but also is thrown into space. There are satellite observations of earth at night which show many bright areas at the most parts of continents. All the light ejected into space is energy loss. In Japan, we measure night sky brightness at observing points larger than 100 every half year and find the night sky brightness is brighter and brighter year by year. There is an international tendency that an amount of useless light ejected into space is growing probably because of careless design of a lighting system. An important consequence of bright night sky is not only loss of energy but also loss of stars which brings loss of a proper cosmic understanding.
|