Sky Over Antarctica Glowing Electric Blue from Ice Clouds

Something weird happened recently in the skies over Antarctica: sparkling blue flashes pulsing around the dark South Pole like an electrified iris around a pupil.

The source of the strange flashes, noctilucent ice clouds, occur under strict atmospheric conditions, and only during a handful of weeks in the year. Seeded by fine debris from disintegrating meteors, noctilucent clouds glow a bright, shocking blue when they reflect sunlight.

And this year, they’ve come early.

NASA’s Aeronomy of Ice in the Mesosphere, or AIM, spacecraft first recorded the sparkling lights on Nov. 17, tying with the earliest start yet in the AIM record of the Southern Hemisphere, the agency said.

(MORE: Former American Astronaut Buzz Aldrin Evacuated from South Pole

Data from NASA’s Aeronomy of Ice in the Mesosphere, or AIM, spacecraft shows the sky over Antarctica is glowing electric blue due to the start of noctilucent, or night-shining, cloud season in the Southern Hemisphere.
(NASA)

“This season … is tied with 2013 for the earliest Southern Hemisphere season in the CIPS data record,” Cora Randall, a member of the AIM science team at the University of Colorado, told EarthSky. “This was not at all a surprise: The Southern Hemisphere polar stratospheric winds switched to their summer-like state quite early this year.”

Noctilucent clouds form in the mesosphere, nearly 50 miles above the Earth's surface, where so few air molecules exist that it becomes extremely difficult to produce ice crystals. But when conditions are just right - namely, a temperature below minus-207 degrees Fahrenheit - tiny cubic ice crystals can form at latitudes greater than 40 degrees.

Since its 2007 launch, AIM data has shown that changes in one region of the atmosphere can impact responses in another distinct, and sometimes distant, region, NASA said. It's a phenomenon scientists call atmospheric teleconnection.

In addition to appearing earlier in the year, noctilucent clouds have spread to regions beyond the poles, NASA said in 2013 press release.

"When noctilucent clouds first appeared in the 19th century, you had to travel to polar regions to see them," the release states. "Since the turn of the century, however, they have been sighted as close to the equator as Colorado and Utah."

James Russell, a principal investigator of AIM, told Tech Times that growing methane content in the atmosphere could be responsible for the early onset as it allows more water vapor to be loaded into ice crystals leading to these clouds.

https://www.wunderground.com/news/nasa-detects-early-noctilucent-ice-clouds-over-antarctica