The 2014 Nobel Prize in Physics was recently awarded to three scientists (Isamu Akasaki, Hiroshi Amano, and Shuji Nakamura) for inventing the blue light-emitting diode (LED) roughly 20 years ago.

Once upon a time, buying a lightbulb meant choosing an incandescent one of between 25 and 100 watts, depending on how bright you wanted the light to be and the fixture you were putting it in. You ...