On January 28, a green laser could be seen silently tracing a route towards the horizon above the Hawaiian islands, resembling a glitch in the Matrix’s programming. From a telescope atop Hawaii’s highest summit, the scene was captured on camera.
Fortunately, this wasn’t some extraterrestrial spacecraft looking for life on Earth. It appears that the enigmatic green beams were launched by an orbiting satellite. but not the one we had in mind.
The camera’s co-owner, the National Astronomical Observatory of Japan (NAOJ), initially declared on Twitter that the green light was most likely coming from a radar unit on an orbiting satellite called ICESat-2.
The NASA-owned ICESat-2 monitors the extent of the ice sheets, forests, and sea ice covering the planet. However, NAOJ revised their video of the laser beam on February 6, 2022, stating that it was unlikely to be NASA after all based on the trajectory.
It is not by their instrument, but by others, claims Dr. Anthony J. Martino, a NASA scientist who is working on ICESat-2 ATLAS, according to a note on the YouTube video.
Daqi-/AEMS Set As A Support
The Chinese Daqi-1/AEMS satellite was determined to be the most likely option for the ACDL instrument by his coworkers, Dr. Alvaro Ivanoff et al., who ran a simulation of the orbital paths of satellites that carried a similar sensor.
Using devices of a similar type, his collaborators Dr. Alvaro Ivanoff and others completed a simulation of the satellites’ trajectories and determined that the Chinese Daqi-1/AEMS satellite was the most likely candidate for the ACDL device.
“We greatly appreciate their efforts in identifying the light,” We apologise for any uncertainty we may have caused on this incident and its potential effects on the ICESat-2 crew.
Launch Of China’s Satellite
Similar to ICESat-2, China’s Daqi-1 satellite was launched in April of last year to study the atmosphere. That indicates that it is orbiting the planet to keep an eye on air pollution and the amount of carbon in the atmosphere.
Daqi-1 is equipped with five equipment, among them the ACDL (Aerosol and Carbon Dioxide Detection Lidar). Lidar, which stands for laser imaging, detection, and ranging, functions somewhat similarly to sonar.
But it sends out laser beams to map the region instead of sound waves.
These lasers are also thought to be what lighted up the sky over Hawaii towards the end of January. With ACDL, different compounds in the Earth’s atmosphere can be found by sending out dual-wavelength lasers at particular wavelengths.
A Dawn Of China’s Space Expedition
The amount of time it takes for these laser beams to bounce back reveals details about the atmosphere and earth below. By generating two 1572 nanometer-wavelength alternate lasers, for instance, ACDL can determine how much CO2 is present in Earth’s atmosphere.
The China Aerospace Science and Technology Corporation, the company that developed Daqi-1, stated in a press release from March 2021 that Daqi-1 “can monitor fine particle pollution like PM2.5, pollutant gases including nitrogen dioxide, sulphur dioxide, and ozone, as well as carbon dioxide concentration.”
Daqi-1 is still in its infancy, thus we have not yet received the scans’ results. The satellite is only the beginning of China’s attempts to monitor air pollution, though, if all goes as planned.
In the future, China will build a number of Daqi satellites, which will be used to monitor atmospheric pollution, support environmental authorities with remote sensing data, and aid scientific research into global climate change, according to a March 2021 press release.
“Daqi-1 will be networked with other satellites, including Daqi-2,” according to the statement, “to realise greenhouse gas monitoring and assist China in decreasing carbon emissions.”
It will be interesting to watch if China succeeds in deploying these green atmosphere-detecting lasers.