Although pointing high-energy lasers at the sky to cause pouring rain is currently a high-tech dream, the motivation behind controlling the weather has existed since the days of our ancient ancestors.
Throughout human history, many civilizations developed magical or religious methods in an attempt to increase or decrease precipitation.
In light of this history, current techniques that shoot laser beams or launch chemicals into the sky for the same purpose seem to be just the latest manifestation of this goal.
Nevertheless, these cloud seeding techniques are controversial, both for their effectiveness at inducing rainfall and for their possible harmful side effects. In a recent review paper published in the IOP’s Journal of Physics D: Applied Physics, a team of scientists from Switzerland and Germany has examined the latest results of laser-induced condensation and discussed the future of the field.
One of the first successful demonstrations of laser-induced condensation came just last year, when researchers – including the authors of the current review – used a powerful laser to produce tiny water particles in moderately humid air.
The water particles were just a few micrometers in diameter, which is about 100 times too small to fall as rain droplets. However, the experiments demonstrated the ability to transform particles in a gas phase to a liquid phase through condensation, and larger droplets are expected to be feasible.
“At this stage, our work clearly shows that lasers can induce the formation of tiny particles,” Jérôme Kasparian of the University of Geneva in Switzerland told Phys.org. “This is not, at least at this stage, efficient cloud seeding for making rain, but rather a newly opened direction for research in this direction.”