It is an unfortunate fact of today's life that most people are growing up unable to see the stars that our grandparents knew so well. The prime night sky exists only in pictures or at a planetarium. We have lost our view of the stars, and we have mucked up our nighttime environment as well. Such a loss might be acceptable if light pollution were the inevitable price of progress, but it is not.
Most sky glow is unnecessary.
The light that obscures our view of the night sky comes mainly from inefficient lighting sources that do little to increase nighttime safety, security, or utility. They produce only glare and clutter, costing more than one billion dollars annually in the U.S. alone. For astronomy and science, the impact has been even more dramatic. Astronomers require observations of extremely faint objects that can be made only with large telescopes at sites free of air pollution and urban sky glow. For example, scientists interested in how the universe was formed may study the light of galaxies and quasars at enormous distances from Earth.