Stunning Noctilucent Cloud Phenomenon Lights Up Summer Night Sky
(WorldNews Environment)

Once rare, but now becoming increasingly common, noctilucent, or “night-shining”, clouds form in the upper part of Earth`s atmosphere, tens of kilometers above weather clouds, at mid-latitude locations. As the lower atmosphere warms during the summer months, air is circulated upwards where it expands and cools in the Mesosphere, around 80 kilometers (50 miles) above sea level. If there is enough water vapor in these cold...