The sky above Antarctica glowing in electric blue has made big news after NASA updated about the arrival of noctilucent, or night-shining clouds, in the Southern Hemisphere.
In terms of looks, the luminescent clouds are looking wispy as in a blue-white aurora borealis when seen from the ground. The same looks like a blue gossamer haze when seen from space.
The data and images sent by NASA's Aeronomy of Ice in the Mesosphere spacecraft (AIM) above the Antarctic sky showed the sky as radiating bright with electric blue color.
What makes it special this year is their early arrival, stumping scientists who suspect it as yet another manifestation of the warming of Arctic region.
Some scientists hold the view that this corresponds to an earlier seasonal change at lower altitudes. NASA spokesperson Lina Tran explained that the clouds were seeded by fine debris from disintegrating meteors.
Since its launch in 2007, AIM spacecraft has been monitoring the atmosphere. Data show that changes in one region of the atmosphere also affect another region in what is called as "atmospheric teleconnections".
The spacecraft's evolving orbit has come handy in measuring the atmospheric gravity waves that are contributing to these teleconnections.
"AIM studies noctilucent clouds in order to better understand the mesosphere, and its connections to other parts of the atmosphere, weather and climate. We observe them seasonally, during summer in both the Northern and Southern hemispheres. This is when the mesosphere is most humid, with water vapor wafting up from lower altitudes," NASA explained in a statement.
Early Arrival Of Noctilucent Clouds
As mentioned, the early start of blue shining clouds this year — from Nov. 17 instead of late November or early December — has baffled scientists. So there is more mystery in the early start of the shining clouds season in the Southern Hemisphere.
Considered the highest and coldest clouds of Earth, Noctilucent clouds are normally spotted around 50 miles above the Earth's surface in the mesosphere region.
The blue shine happens when ice crystals formed from the interaction of water vapors with the dust, and micro-debris from meteors start reflecting when sunlight falls on them.
One pivotal explanation to the phenomenon was offered by James Russell, a principal investigator of AIM. He said growing methane content in the atmosphere could be responsible for the phenomenon as it allows more water vapor to be loaded into ice crystals leading to these clouds.
Gary Thomas, a professor at the University of Colorado, calls noctilucent clouds a relatively new phenomenon.
"They were first seen in 1885,' about two years after the powerful eruption of Krakatoa in Indonesia, which hurled plumes of ash as high as 80 km into Earth's atmosphere," he said. But even after the ash dispersed, the clouds persisted.
The onset of night-shining clouds coinciding with the early arrival of summer in the Antarctica is a matter of concern for climatologists and NASA.