A photographer has captured a spectacular image of an eerie atmospheric phenomenon known as "night-shining" clouds.
Ollie Taylor snapped the "noctilucent" clouds (NLCs) over a 12th century church—located within a Neolithic henge monument—in southwestern England at around 2 a.m. on June 22.
NLCs are rare clouds that appear very high in the night sky, usually on clear summer nights. They form in the mesosphere—the upper part of Earth's atmosphere—at altitudes of around 50 miles, making them the highest clouds in the atmosphere.
Read more
Electrical Activity in Animals Is Similar to Atmospheric Electric Fields
209-MPH Wind Gust Measured at California Peak Could Be a Record-Breaker
'Gargantuan' Hail Pelted Argentine City, Including Potential Record-Breaker
Consisting of collections of ice crystals, NLCs only become visible during twilight when the sun illuminates them from below the horizon—usually about the same time that the brightest stars appear in the sky, according to the U.K. Met Office.
The clouds, which often appear bluish or silvery in color, can usually only be seen between latitudes of 45° and 80° in the northern and southern hemispheres. However, there is very little land between these latitudes in the Southern Hemisphere, meaning sightings there are much less common.
NLCs require the same ingredients as other clouds to form—water vapor, dust, and very low temperatures. The latter are common in the mesosphere, however, water vapor and dust are not.
Relatively little is known about these clouds, but scientists think that dust from tiny meteors in space may enable them to form, although dust from volcanoes or man-made pollutants could also play a role.
It is possible that the required moisture may travel into the mesosphere through gaps in the tropopause—the boundary between the lowest part of the Earth's atmosphere, the troposphere, and the layer above, the stratosphere. However, there is also a chance that chemical reactions between methane and other substances could produce the moisture needed for the clouds to form.
The first documented mention of the clouds was in 1885, around two years after the catastrophic eruption of the Krakatoa volcano in Indonesia. While NLCs are a relatively rare phenomenon, there have been an increased number of sightings in recent years, which some have linked to rises in greenhouse gas emissions, according to the European Space Agency (ESA.)
