Wires made by a team of Harvard University researchers are almost too small to imagine – thousands of times thinner than a human hair and just millionths of an inch long. The long-term result may be computers much smaller and faster than the speediest supercomputers available today. Such supercomputers would be super cool, operating at about minus 458 degrees Fahrenheit. How small can such machines be? That depends on how small their wires can be made and still function as superconductors. No one knew the lower limits until Harvard physicists provided the first answer: roughly 5 millionths of a millimeter across (5 nanometers), or about 200 thousandths of an inch.