Environmental Pollution
A clean atmosphere is indicated by the fact that the Milky Way is visible. Comparing the zenith with the horizon, shows how the "blue quality" is degraded depending on the amount of air pollution and dust. The twinkling of a star is an indication of the turbulence of the air. This is of importance in meteorology and for the "seeing" of astronomy.
Light pollution is a significant problem for amateur astronomers but becomes less late at night when many lights are shut off. Air dust can be seen even far away from a city by its "light dome".
Read more about this topic: Naked Eye
Famous quotes containing the word pollution:
“Like the effects of industrial pollution ... the AIDS crisis is evidence of a world in which nothing important is regional, local, limited; in which everything that can circulate does, and every problem is, or is destined to become, worldwide.”
—Susan Sontag (b. 1933)