Noctilucent clouds are Earth's highest clouds. It is located between the Earth and space 50 miles above the ground in a layer of the atmosphere called the mesosphere. The mesosphere is directly above the stratosphere and below the thermosphere. Seeded by fine debris from disintegrating meteors, these noctilucent clouds of ice crystals glow a bright blue color when they reflect sunlight.
Know The Noctilucent Clouds
Noctilucent clouds (NLCs), also known as Polar Mesopheric Clouds (PMCs), are tenuous cloud-like phenomena that are the "ragged edge" of a much brighter and pervasive polar cloud layer called polar mesospheric clouds in the upper atmosphere, visible in a deep twilight. They are made of ice crystals. The word noctilucent means night shining in Latin.
They are the highest clouds in Earth's atmosphere, around 76 to 85 kilometers (47 to 53 mi). They are normally too faint to be seen and are visible only when illuminated by the sunlight from below the horizon while the lower layers of the atmosphere are in the Earth's shadow. Noctilucent clouds are not fully understood and are a recently discovered meteorological phenomenon
NASA's AIM Captures The Highest Ice Clouds Over Antarctica
The Aeronomy of Ice in the Mesosphere (AIM) is a satellite to conduct a 26-month study of noctilucent clouds. It is the ninetieth Explorer program mission and is part of the NASA-funded Small Explorer program (SMEX). AIM's focus is to study NLCs. Its mission will help determine what factors — temperature, water vapor, and dust particles — lead to the formation of these clouds.
According to Space Daily, AIM saw the start of noctilucent cloud season on Nov. 17, 2016 - tying with the earliest start yet in the AIM record of the Southern Hemispheres since the beginning of their observation. Scientists say this corresponds to an earlier seasonal change at lower altitudes. In the Southern Hemisphere, AIM has observed seasons beginning anywhere from Nov. 17 to Dec. 16.
Changes in one region of the atmosphere can affect even distant regions, which scientists call "atmospheric teleconnections." Since its 2007 launch, AIM data has shown us that changes. Now, due to natural precession, the spacecraft’s orbit is evolving, allowing the measurement of atmospheric gravity waves that could be contributing to the teleconnections.
