So far, the technology has succeeded in creating tiny droplets of water, less than 0.01 millimeters in diameter. For the particles to be heavy enough fall as rain, they would have to be at least one hundred times bigger. However, it may be possible to induce these tiny droplets in water that is headed towards a natural feature such as a mountain range. As the air is forced to rise over the mountain range, it will cool, causing the droplets to grow larger until they are eventually heavy enough to fall as rain.
So how does it work? The laser beam causes particles of nitric acid to form in the cloud. Nitric acid forms bonds with water vapour in the air, acting as a means of bringing water molecules together so that condensation into liquid water takes place. The nitric acid-bonded water droplets have increased stability, so are less likely to re-evaporate than naturally formed droplets.
To read more about the significance of the technology, and the old silver iodide method that it could potentially replace, follow this link:
Making Rain With Laser Beams
*Image courtesy of Flickr user openuser