Lightning is one of the scariest things to happen somewhere fifty times every second. Enormous bolts of electricity, hotter than the surface of the Sun, strike the Earth from above with little or no warning, frying trees, buildings, people, and everything else in the way to most efficienctly ground themselves. Nevermind the trees, but buildings and people tend to react badly to being struck by lightning, which is why scientists at the University of Arizona and the University of Central Florida are using lasers to try and steer lightning in other directions.
The idea of shooting lasers into the air to affect weather has been experimented with before, with successful tests of lasers performing limited lightning control in the lab. However, there was always one major problem: the lasers aren't capable of traveling long distances through the air to where the lightning originates. The issue is that high-intensity lasers lose energy very quickly. In fact, in lab experiments, these laser beams could only travel a few feet at the most.
The researchers have solved this problem with new laser technology. Instead of shooting a single laser beam, they shoot one beam wrapped within another beam into the sky really, really fast: over just a billionth of a millionth of a second. This second beam, called a "dress beam," isn’t as intense as the first: it has a long constant range that provides energy to the first beam, reinforcing it as it travels. This results in a very quick and very powerful laser beam that doesn’t bend at longer distances. In the lab, this meant a beam that traveled a total of seven feet, significantly farther than the original undressed beam.
The top image shows what happens with a single high-intensity laser with a limited range before diffusion. The bottom image shows new laser technology that involves a "dress beam" around the first beam to create a longer-range high-intensity beam.
The basic concept is to use this technology for controlling lightning bolts. As these laser beams fly upwards, they generate ionized molecules that provide an easy path for lightning to take to the ground. This lightning can then be diverted to a different remote location free of people and buildings. Sounds great in theory, but we still have a lot farther to go from the current range of seven feet.