A laser has been used to generate small clouds on demand in lab, and real-world experiments suggest this could be a way to call down rain when it’s needed.
People have experimented with cloud seeding for decades in the hope of boosting rainfall, usually by sprinkling silver iodide crystals into clouds high in the atmosphere.
These crystals encourage large water droplets to form around them, and the droplets then fall as rain – in theory, at least. “The efficiency of this technique is controversial,” says Jérôme Kasparian at the University of Geneva, Switzerland, one member of a research team that think lasers may be a better way to trigger rain on demand.
Kasparian and colleagues have just reported the first successful use of this technique to summon clouds from air both in the lab and in the skies over Berlin, Germany.