Mysterious Night-Shining Clouds Glow Above Northern Ireland (Photo)

Noctilucent Clouds Above Ireland — Astrophotographer John McConnell took the images on June 20, 2014 from Maghaberry, Northern Ireland. (Image credit: John C McConnell)

Electric-blue noctilucent clouds glimmered in the sky just before dawn when this amazing image was captured.

Astrophotographer John McConnell took the photo on June 20, 2014 from Maghaberry, Northern Ireland.

Noctilucent clouds or NLCs are blue-white clouds that are so bright they can be seen in the twilight sky. They typically form about 50 to 53 miles (80 and 85 kilometers) above ground in the atmosphere, at altitudes high enough to reflect light even after the sun has slipped below the horizon. [See more images of these mysterious clouds]

"This was the best display since the 2009 season," McConnell wrote in an email to Space.com

These rare clouds form in an upper layer of the Earth's atmosphere called the mesosphere during the summer, visible only when illuminated by sunlight from below the horizon. Scientists speculate the water molecules in these clouds stick to dust associated with matter from outer space. Upwelling winds during the summertime can carry water droplets from the moist lower atmosphere toward the mesosphere. These droplets, combined with tiny particles of what could be meteoroid dust, can create the noctilucent cloud.

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Nina Sen is a freelance writer and producer who covered night sky photography and astronomy for Space.com. She began writing and producing content for Space.com in 2011 with a focus on story and image production, as well as amazing space photos captured by NASA telescopes and other missions. Her work also includes coverage of amazing images by astrophotographers that showcase the night sky's beauty.