NOCTILUCENT CLOUDS

NOCTILUCENT CLOUDS

This morning in Northern Ireland, the usual rosy glow of sunrise was fringed with electric blue. "We had quite a stunning display of noctilucent clouds," reports photographer Noel Blaney, who sends this picture from the city of Bangor in County Down:

 

"This was the 3rd significant display of the season," says Blaney.

He can expect the apparitions to become more frequent. Noctilucent clouds (NLCs) are a summertime phenomenon, and the clouds generally grow brighter and more widespread after the summer solstice, which is only days away.

NLCs are Earth's highest clouds. Seeded by meteor smoke and boosted by the greenhouse gas methane, they float 82 km above Earth's surface at the edge of space itself. The natural habitat of noctilucent clouds is the Arctic Circle. In recent years, however, they have spread to lower latitudes with sightings as far south as Utah and Colorado. This will probably happen in 2014 as well.

Observing tips: Look west 30 to 60 minutes after sunset when the Sun has dipped 6^o to 16^o below the horizon. If you see luminous blue-white tendrils spreading across the sky, you may have spotted a noctilucent cloud.

 

From SpaceWeather.com