[In Depth] Your self-driving car could kill radio astronomy
Add energy-saving streetlights, self-driving cars, and balloon-borne internet services to the threats facing astronomers needing dark skies free of electromagnetic smog. The rise of all three technologies is posing new challenges to ground-based researchers who use the optical and radio spectrum to observe the universe, speakers warned earlier this month at the annual meeting of the American Astronomical Societ in Grapevine, Texas. The main problem with light-emitting diodes (LEDs) is not that they are brighter; it's that they are the wrong color. With a large element of blue light, which is preferentially scattered by the atmosphere, LEDs help create more of a light "haze" that obscures the view of telescopes. For radio astronomers, broadcasts at nearby frequencies can fill protected bands with an electromagnetic fog that mars observations. As the sources multiply, astronomers seeking ever-fainter signals from the cosmos are in the position of someone trying to listen to an...