Rain by laser

In the future, lasers can become a more effective rain-generating tool for all existing rain-generating techniques.

>>>To energize aircraft with lasers

Clouds form when steam rises, meet a cold environment and condense into droplets of water or ice around microscopic particles in the gas. People call these microscopic particles 'cloud nuclei' . As the number of cloud nuclei increases, many drops join together to form larger droplets. When the volume is large enough the drops fall and form rain.

A series of rain-generating techniques were born in the war against humanity. Their basic principle is to release microscopic particles - like dry ice or silver iodine - into the air to create clouds and rain.

"However, rain-generating techniques are becoming controversial ," said Jérôme Kasparian, a physicist at the University of Geneva in Switzerland.

Controversy arises because many people doubt the effectiveness of cloud making techniques. For example, airplanes often spread chemical particles on a large scale, while air characteristics vary by region and time. Therefore, assessing the impact of chemicals on the atmosphere is difficult.

Livescience said Kasparian and colleagues studied the technique of laser rain generation. In tests with infrared lasers on the Rhone River in Switzerland, the team found that lasers can produce droplets of a few microns in diameter (one micron equal to a millionth of a meter) even when degrees Air humidity is relatively low (less than 70%). However, the drops are not big enough to create a rain.

'At that moisture, condensation cannot occur under natural conditions,' Kasparian told Livescience .

Laser beams can cause a variety of chemicals to become 'cloud nuclei' - like nitric acid - that form in the air. Those particles tend to bind to water molecules. They act as glue, which means keeping the water droplets together in relatively dry conditions. If they do not exist, the dry state of the air will cause them to evaporate.

'We still cannot create any rain with a laser. Laser beams can create tiny water particles and increase their size, but their size is still limited to a few millionths of a meter. Their size must be 10 to 100 times larger to be large enough to produce rain , 'Kasparian said.

Kasparian judged that if people overcome the aforementioned obstacles, we will not need to use an airplane to fire lasers.

'The types of lasers we are using can reach a height of several kilometers, so we only need lasers from the ground , ' he said.

According to Kasparian, combining lasers with other cloud-forming techniques is not a wise idea, because that combination will create too many 'cloud nuclei'.

'Creating too many microscopic particles can cause the opposite effect, because the particles will scramble for water vapor in the atmosphere. Because of the competition between too many beads, the droplets will be so small that they cannot fall to become rain , 'he explained.