Mysterious green glow in Hawaii sky likely rare atmospheric phenomenon
A mysterious green ripple in the sky over Hawaii has flummoxed the government and military, but a rare atmospheric phenomenon is likely the culprit.
A strange green ripple was seen in the sky over Kailua-Kona in late April.
A video showing a mysterious green glow in the sky during sunset above Hawaii this weekend has perplexed officials.
KHON reports that the sight over Keahole Point on Saturday and Sunday flummoxed officials at the local Army base, Department of Transportation and Observatory. However, a rare low-light atmospheric phenomenon was the likely culprit.
A green sky over Hawaii at sunset on April 25 and April 26. (Jake Asuncion)
A natural assumption would be that this green color was from the northern lights. But for the aurora borealis to be seen in Hawaii, an extreme geomagnetic storm would have to be in progress, as Hawaii is mostly below the latitude of Cuba.
Another explanation might be a green flash, but this occurs on the ocean at sunset, not farther in the sky after sunset.
The most likely explanation is an event known as "airglow" rippled by gravity waves. There are several examples of similar green, banded skies from airglow events in Kansas in 2001 and Chile in 2016. Astronauts on the International Space Station have also taken photos of a ring of green and red airglow encircling the Earth.
An astronaut onboard the International Space Station took this nighttime panorama while looking north across Pakistan’s Indus River valley. Airglow can be seen at the top of the photo. The winding border between Pakistan and India is lit by security lights that have a distinct orange tone. (NASA)
Airglow forms at similar heights to the aurora, according to Atmospheric Optics. Green light from oxygen atoms excited by the sun's ultraviolet rays glows 60 miles above the Earth's surface. Slow moving gravity waves create banded structures.
While photos exist of airglow, you won't be able to see it with your naked eye. The light generated is below the human threshold of color perception. Airglow can only be seen with low-light cameras or long exposures. That explains why Jake Asuncion, who filmed the green sky, was surprised to see it upon viewing the footage.
Airglow was sighted on a grayscale weather satellite photo in 2012, NASA says, when the gravity waves that disturb the phenomenon were caused by thunderstorms.
Airglow is disrupted by gravity waves from thunderstorms over Texas in 2012. (NASA)
