Light is the great unifier. John Wheeler, the beloved Princeton physicist, used to draw the universe as a big capital U with a little eye on one leg, signifying that we, human beings, are the eyes of the universe looking back at itself. The universe after many, many billions of years formed human life on planet Earth, and we use light to observe and understand the universe.
The growing understanding of the nature of light through the centuries is the perfect metaphor for science: it is an eye-opener. Almost 350 years ago, Isaac Newton, as a young man, put a prism in a beam of light and unraveled its various colors. This was the beginning of a long story. Around the year 1800, the astronomer William Herschel was the first to measure the temperature of light. He made the startling discovery that the rainbow does not stop at red, but actually continues, invisibly, as infrared light, which we cannot see but can feel as a sensation of warmth.
What is light? Physics has a simple answer: an electromagnetic wave. Exactly 150 years ago, the Scottish physicist James Clerk Maxwell discovered the laws that describe these waves. I have a T-shirt with these equations and the text “And then there was light.” If only Maxwell had patented his equations! It would be enough to finance all research in the world.READ MORE>