China's Green Lasers

          China's Green Lasers

• A NASA scientist says a Chinese satellite flashed previously unidentified lights over Hawaii last month.
• Japan originally said the lights came from NASA.
• The green lights are the latest in a string of mysterious objects in the sky.

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China is most likely behind the mysterious green lights that were seen last month in the skies over Hawaii.

The Chinese pollution-monitoring satellite Daqi-1 probably produced the lights spotted over Hawaii on January 28, according to a NASA scientist. The comments apparently put to rest earlier theories that the lights were coming from a U.S. satellite.

The lights were first seen during a live stream. Footage from the Subaru-Asahi Star Camera, which is situated on the Mauna Kea volcano, showed the line of green light quickly flashing across the sky.

A week after the incident, experts at the National Astronomical Observatory of Japan (NAOJ), which co-owns the camera, claimed on Twitter that the green light originated from radar on the NASA satellite ICESat-2. But a week later, NAOJ revised its theory, saying that based on the trajectory, it was unlikely the lights were coming from NASA’s satellite after all.

The Daqi-1 was launched in April. The satellite has LIDAR (laser imaging, detection, and ranging) for detecting atmospheric aerosols and carbon dioxide. Daqi-1 also measures nitrogen dioxide, sulfur dioxide, ozone, and fine particle pollution. Lidar uses laser beams for mapping, and it’s believed that these lasers illuminated the sky over Hawaii in January.

The Daqi-1 isn’t the only satellite using LIDAR to monitor Earth. The Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation (CALIPSO) has been orbiting for more than 15 years. The CALIPSO’s High Spectral Resolution Lidar (HSRL) provided the first global observations of the North Atlantic phytoplankton bloom.

Early NASA experiments proved the value of orbiting LIDAR. For example, the LITE (Lidar In-Space Technology Experiment) was used in 1994 as the first LIDAR system for atmospheric studies from space. The instrument was positioned in the payload bay of Space Shuttle Discovery, measured Earth’s cloud cover, and tracked various particles in the atmosphere.