ENCORE The light bulb needs changing.  Edison’s incandescent bulb, virtually unaltered for more than a century, is now being eclipsed by the LED.  The creative applications for these small and efficient devices are endless: on tape, on wallpaper, even in contact lenses.  They will set the world aglow.  But is a brighter world a better one? Discover the many ingenious applications for LEDs and the brilliance of the 19th century scientist, James Clerk Maxwell, who first discovered just what light is.  But both biologists and astronomers are alarmed by the disappearance of dark.   Find out how light pollution is making us and other animals sick and – when was the last time you saw a starry night? Guests: •  Ian Ferguson – Engineer, dean of the College of Engineering and Computing, Missouri University of Science and Technology •  Jay Neitz – Professor, department of ophthalmology, University of Washington •  Martin Hendry - Professor, gravitational astrophysics and cosmology, University of Glasgow •  John Barentine  - Program manager, International Dark Sky Association