Unlike the tubes of old, however, NASA's vacuum-channel transistors measure the gap between electrodes, not in millimeters but in nanometers. Making them nanoscale has a couple of key advantages.

Which is why NASA's Ames Research Center is going back to the future with its new vacuum transistor -- a nanometer-scale vacuum tube that, in early testing, has reached speeds of up to 460GHz.

The next step for the group is to scale down the vacuum tubes and explore their many applications. If their research pans out, the computers of the future may be using technology from a century ...