image stats
rating
2.91
votes
136
views
3174
uploader
Onyma
comments
1
date added
2009-07-20
category
Sport
previous votes
Loading..
Noctilucent clouds
1 star2 stars3 stars4 stars5 stars
Noctilucent clouds

"a group of trees with clouds in the sky"

Rate image:
[ | | ]
[ | ]
Comments for: Noctilucent clouds
Onyma Report This Comment
Date: July 20, 2009 12:13PM

Mysterious, glowing clouds previously seen almost exclusively in Earth’s polar regions have appeared in the skies over the United States and Europe over the past several days.

Photographers and other sky watchers in Omaha, Paris, Seattle, and other locations have run outside to capture images of what scientists call noctilucent (”night shining”) clouds. Formed by ice literally at the boundary where the earth’s atmosphere meets space 50 miles up, they shine because they are so high that they remain lit by the sun even after our star is below the horizon.

The clouds might be beautiful, but they could portend global changes caused by global warming. Noctilucent clouds are a fundamentally new phenomenon in the temperate mid-latitude sky, and it’s not clear why they’ve migrated down from the poles. Or why, over the last 25 years, more of them are appearing in the polar regions, too, and shining more brightly.

“That’s a real concern and question,” said James Russell, an atmospheric scientist at Hampton University and the principal investigator of an ongoing NASA satellite mission to study the clouds. “Why are they getting more numerous? Why are they getting brighter? Why are they appearing at lower latitudes?”

Nobody knows for sure, but most of the answers seem to point to human-caused global atmospheric change.

Continued in the article below...

[www.wired.com]