The laser technique works by using photodissociation. Photons break down atmospheric compounds, which produces ozone and nitrogen oxides. That causes nitric acid particles to form, and those bind water molecules together, creating rain. A challenge for scientists will be to unravel the details of the process, but there are major benefits compared with a chemical approach, such as sending silver iodide particles into clouds. For one, it's easier to plan experiments with lasers, since they have an on-off switch that can be toggled and tested for effectiveness. A laser-induced approach could also be less likely to cause unintended problems in the surrounding atmosphere.