Meet the recently developed 4-stroke nanomotor.  It’s so tiny (five nanometers in length) that it takes nearly four million set side by side to equal the diameter of a penny, it’s shaped like a macaroni noodle, is fueled by solar energy…and they create absolutely no waste.

The process is quite similar to the operation of a standard automotive four-stroke combustion engine, on a infinitely smaller scale, and the exhaust is an electron, rather than pollutants.  It will also continue operating — individually or with others — as long as energy is available, and has been proven, under mild environmental conditions, to remain stable for at least 1000 cycles.  While it’s only 2-12% efficient, the advantage is that sunlight is free, and there’s no need to refuel.

Here’s how they work:

Energy, in the form of photons from sunlight, excites one end of the molecule, which sets off a four-step process. Electrons are transferred along the molecule until they reach the ring structure, causing it to slide 1.3 nanometers forward on the molecule. As the electron continues its path, it reaches a section that recycles it back to the beginning. This causes the molecule to “reset,” and the ring returns, piston-like, to its original position.

The whole process takes about 100 microseconds.

What is the future for these tiny motors?  It’s too early to put them to practical use, but as gas prices rise and the need for power soars as we collect more and more electric devices, alternative fuels always warrant a mention.

Read More | LiveScience