Born of Meteor Dust, Unusual Clouds Appear in the Night Sky

If you look to the darkening sky after the end of a long summer day, you might see tendril-like clouds with a blueish tinge that hang at the edge of space. They appear when conditions are right, generally at latitudes close to the North or South Poles, and only when the Sun is invisible, over the horizon. 

The  to T.W. Backhouse, who, like many other people, took up sky-watching following the cataclysmic eruption of Indonesia’s Mount Krakatoa in 1883. The volcano spurt ash high into the atmosphere,