The Blue Clouds Spotted Hovering Earlier Than Usual Over Antarctic

The blue clouds or also known as noctilucent clouds are seen hovering over the Antarctic earlier than usual. This "night-shining" clouds appear yearly over the frozen continent in late November or early December. On the other hand, NASA said that the noctilucent clouds arrived in mid-November.

The noctilucent clouds are considered the Earth's highest clouds. They are in an upper layer of the Earth's atmosphere known as the mesosphere. These are composed mainly of ice crystals that glow a bright, brilliant blue when they reflect sunlight.

NASA's Lina Tran wrote on her blog that noctilucent clouds provide clues to the mesosphere's connections to other parts of the atmosphere, weather and climate. She explained that this is when the mesosphere is most humid, with water vapor wafting up from lower altitudes. She further explained that this is also when the mesosphere is the coldest place on Earth and drops as low as minus 210 degrees Fahrenheit -- due to seasonal air flow patterns.

NASA scientists stated that on Nov. 17, 2016, the noctilucent cloud season started, which ties the earliest start date on record. These noctilucent clouds have become brighter and beginning to spread closer to the equator, in which the scientists say is a result of the greenhouse gas methane.

Once the methane reached the upper atmosphere, it is oxidized by a series of chemical reactions that create water vapors. The additional water vapors then freeze and produce ice crystals that shape the noctilucent clouds, according to Gizmodo.

These noctilucent clouds were first seen in 1885, a few years after the massive eruption of the Krakatoa, an Indonesian volcano. The people thought it was the result of an explosion. Meanwhile, the scientists said that the clouds are a signal of global warming. On the other hand, some said they came from space dust remnants in the atmosphere, in which NASA supports this theory, according to Christian Science Monitor.