We've seen some fairly small electric cars in recent years, such as those made by Tango, Think, Wheego, and of course, smart. All of those automobiles are absolute monsters, however, compared to what scientists from Swiss research group Empa have created. Working with colleagues at the Netherlands' University of Groningen, they've built a one-of-a-kind electric car that measures approximately 4 x 2 nanometers.

Constructed from a single molecule, the nano car sports four-wheel drive, with each "wheel" acting as a separate motor. It is able to travel in an almost straight line, across a copper surface. Instead of carrying its own battery, the car receives electricity from the tip of a scanning tunneling microscope, positioned above it. People who dismiss EVs because of their limited range, however, aren't likely to be impressed - the nano car requires a 500-millivolt charge once every half-revolution of its wheels.

When the car receives a fresh jolt, the electrons tunnel through the molecule, causing reversible structural changes in each motor/wheel. Ideally, these changes will cause all four wheels to simultaneously turn forward. In practice, it took some doing to get them all coordinated. Ultimately, however - after ten electrical stimulations - the nano car was observed to have moved forward six nanometers. Reversing isn't possible.

The video below shows a side-view simulation of the way in which the nano car moves - a tiny pair of shock absorbers might be a good addition.

While some people might think that creating a tiny car was a worthwhile project in and of itself, the Empa/Groningen researchers have more practical considerations in mind. The car represents a step toward "molecular transport machines," which could be of great use in nanoscale technology. It is hoped that subsequent nano vehicles could receive power in the form of light, such as directed UV laser beams.

A paper on the research was recently published in the journal Nature.