Astronomers have used a homemade motion-detecting camera to capture the mysterious green laser beam

Fujii, director of the Hiratsuka City Museum, captured three dazzling green lights streaking across the night sky -- something Japanese astronomers had never seen before.

As Fujii took a closer look, he realized that as the beam of light streaked across the sky, a small green dot briefly appeared in the clouds above.

The flashing dot gave Fujii a clue that it was a satellite, so he checked the orbital data and found that NASA's Ice, Cloud and Land Elevation Satellite 2, or ICESat-2, was overhead that night.

This striking footage marks the first time the ICESat-2 team has seen footage of the satellite's green late beam from Earth. The talented Fujii also recently captured the meteorite that crashed into the moon last month.

"ICESat-2 appears to be almost directly above him, with the beam hitting the low clouds at an Angle," said Tony Martino, ICESat-2 instrument scientist at NASA's Goddard Space Flight Center in Greenbelt, Maryland.

"To see lasers, you have to be in the right place at the right time, and you have to have the right conditions."

What is a laser beam?

The ICESat-2 satellite uses Lidar to measure the height of Earth's ice, water and land surfaces from space. Its laser instrument fires 10,000 times a second, sending six beams of light to Earth to measure how long it takes for individual photons to bounce off the surface and return to the satellite.

The program calculates ice loss in Greenland and Antarctica, looks at how much polar ocean is frozen, determines the height of freshwater reservoirs, maps shallow sea areas and more.

NASA says lasers are harmless and hard to spot. Attempts have been made to photograph it in the past, with little success, with Martino explaining that the camera requires the laser to bounce off some object in order to see the beam.

On the night Fujii's camera caught the laser, there were enough clouds to scatter it so that the camera could see it, but not so many that the light was completely blocked. Martino added that if a person stood directly under the satellite and looked up, the laser would be more powerful than a camera flash from 100 yards away.

Source: Laser Net