Researchers in the Netherlands have created a car, made of a single molecule, that is both fully electrical and actually drivable. They built the "car," which they say is one billionth the size of a VW Golf, by fashioning a molecule into a long body and four paddle-like structures that act like wheels. They then used a tiny stylus to direct electron pulses at the wheels, to make them move a quarter turn at a time; the wheels then tried to reset to a more molecularly optimal position, which moved them forward again. They also found that by freezing the car with temperatures as low as 7 kelvin, they could move it even more efficiently.

It's still an early test, more proof of concept than useful technology — the car can't move backward, and takes a relatively huge amount of energy to move a tiny distance (six nanometers). The researchers are now working on controlling the car using light, which might be more efficient. Either way, though, the ability to reliably control and move a motor at such a small level could be a big advance for nanotechnology, and could have implications on how we build larger-scale motors as well.