Eerie Green 'Digital Rain' Filmed Moving Across The Sky
By Dave Basner
February 9, 2023
Gazing out into space you'll see stars, planets, the moon and perhaps even be treated to a meteor shower, but you probably aren't expecting to see what was captured on camera last week - strange green lasers shooting down to Earth. That's just what happened over Hawaii but if anyone watching blinked, they might've missed it.
Fortunately, the spectacle was filmed by the Subaru-Asahi Star Camera, which is attached to the dormant volcano Mauna Kea on Hawaii's Big Island. The camera is owned by the National Astronomical Observatory of Japan, which shared to Twitter and YouTube an image and video of what was captured. In their tweet, the observatory explained, "The lights are thought to be from a remote-sensing altimeter satellite ICESAT-2/43613."
On Jan 28, 2023, HST, Subaru-Asahi Star Camera captured green laser lights in the cloudy sky over Maunakea, Hawai`i. The lights are thought to be from a remote-sensing altimeter satellite ICESAT-2/43613.— Subaru Telescope Eng (@SubaruTel_Eng) January 31, 2023
Watch the video:https://t.co/xqoJvSa24s#SubaruTelescope pic.twitter.com/5hhIsewuNp
That satellite, owned by NASA, uses lasers to measure altitude, specifically of ice on the planet. The beams are fired down to Earth and the length of time they take to bounce back reveals altitude. NASA gave a more technical explanation saying:
"The pulses of light travel through a series of lenses and mirrors before beaming to the ground. This pathway along the optical bench serves to start the stopwatch on the timing mechanism, check the laser's wavelength, set the size of the ground footprint, ensure that the laser and the telescope are perfectly aligned, and split the laser into six beams. About 20 trillion photons leave ATLAS through its box structure with each pulse; only about a dozen return to the satellite’s telescope. To catch these photons, ATLAS is equipped with a beryllium telescope, 2.6 feet in diameter."
The machine can fire up to 10,000 laser pulses in one second, which might explain why those who have seen what it looks like refer to it as "digital rain." You can learn more about NASA's space lasers at their ICESAT website.