Light pollution, simply put, is any unnecessary or excessive outdoor illumination. Sadly, it’s become a pervasive and ugly consequence of modern 24/7 society.

Light pollution robs us of the night sky’s beauty, negatively affects the ecosystem, and creates an in-your-face waste of energy. But a new mindset and new technology are poised to slow  and perhaps reverse this bane of modern life.

Kelly Beatty has been explaining the science and wonder of astronomy to the public since 1974. An award-winning writer and communicator, he specializes in planetary science and space exploration as Senior Editor for Cambridge-based Sky & Telescope magazine. Beatty enjoys sharing his passion for astronomy with a wide spectrum of audiences, from children to professional astronomers, and you’ll occasionally hear his interviews and guest commentaries on National Public Radio and The Weather Channel. He served for a decade on the Board of Directors for the International Dark-Sky Association. He will speak in the Weld Hill Building of the Arnold Arboretum on Tuesday, July 16 at 7 pm, sponsored by Greening Rozzie, Boston City Counselor Michelle Wu, and the Boston Food Forest Coalition. The program is free but registration requested at 617-384-5277, or at www.my.arboretum.edu.