How far can lasers be?

According to an aviation security officer, green laser lights can light the lights on the aircraft, affecting pilots driving airplanes. So how much can a laser pen reach the maximum distance?

According to Kotaku, Takayuki Ohira, the inventor of the MEGASTAR astronomical projector , conducted an experiment to find the laser's limit and publish the results on Twitter. He used a laser projector with a capacity of 1mW (equivalent to 0.001W) to direct a laser beam into a high-rise building from a distance of 20km to see if the naked eye of the person could see the laser light well. is not.

Ohira's experimental simulation.

Ohira received the support of Japanese astronaut Soichi Noguchi, who will stand in the building and take a photo of the laser beam from his phone.

Ohira also warned that others should not perform similar tests. Ohira's experiment was conducted at night, he also calculated the temperature and weather conditions, and the distance was safe enough for the laser to not harm the retina.

Red laser photo taken from a distance of 20km.

In 2012 alone, there were more than 3,000 cases of pilots piloting disoriented by laser beams into the cockpit.

Ohira said: " If the laser can be seen with the naked eye, it can also be identified by a sensor. Therefore, you can use the laser as a signal to communicate with each other." . After this test, Ohira also hopes to carry out further tests.

Ohira's test was performed with a 1mW laser projector, equivalent to a conventional laser pen. But if using a 1500mW laser projector, Ohira could do more. He thought that he could project lasers to the moon.