If the answer is yes, you can thank Charles K. Kao, Willard S. Boyle and George E. Smith, who won the 2009 Nobel Prize in Physics last week.

Four decades ago, the men produced key scientific insights that have led to fiber-optic data transmission and digital photography.

Those two technologies today exist side by side -- or more precisely, one in front of the other -- in the endoscopes that are ubiquitous in diagnostic medicine and surgery.

Or course, fiber-optic cable is responsible for carrying much of the information, voices and pictures that ceaselessly course around the planet. And "charge-coupled devices," or the guts of digital cameras, have changed the recording of images from a chemical process into an electronic one.

Rarely has there been a Nobel Prize whose relevance to the ordinary person is as indisputable as this one.

"Taken together, these inventions may have had a greater impact on humanity than any others in the last half-century," said H. Frederick Dylla, director of the American Institute of Physics.

Although the discoveries involve important theoretical insights, they both arose from serious wrestling matches with practical problems.

In the early 1960s, Kao was a young engineer at Standard Telecommunication Laboratories, the research arm of a British telephone company. His assignment was to see whether light might be an alternative to microwaves as a vehicle for transmitting information over long distances.

The problem was that light beams sent through the atmosphere were not stable. So Kao considered the possibility of using glass as a conduit.

While light normally passes through glass and does not go around corners, Kao's work -- aided by that of many other scientists and engineers -- is proof that under the right conditions, those generalities do not hold true. Sometimes light can be kept inside a strand of glass, like water in a pipe.

This is achieved by exploiting light's tendency to bend when it passes from one transparent medium into another. That phenomenon, called "refraction," occurs because the velocity of a beam of light slows, and its wavelength shortens when it enters a "slower" (usually denser) substance.