The cynics might say that there's no practical use for any of this, that there might be other uses for all the money and brainpower going into these machines. But we live in a civilization shaped by physics. Computers use microprocessors, devices that would not exist without the discoveries of modern physics. The World Wide Web was invented thanks to research at CERN by computer scientist Tim Berners-Lee. The iPod couldn't exist without something called "giant magnetoresistance," discovered by physicists in the late 1980s without much thought of how it might eventually be used. Of course, many discoveries in physics have applications that are less beneficial for humanity. We know, for example, that the forces within an atom are so powerful that, unleashed and directed against humankind, they can obliterate cities in an instant.