Normally rare noctilucent (“night shining”) clouds, which glow during the evening, are starting to move out of the polar regions to which they are normally confined, according to detailed pictures taken by a new NASA satellite.
Noctilucent clouds form 50 miles above the Earth’s surface, usually above the North and South pole during the summer months.
The "Aeronomy of Ice in the Mesosphere” (AIM) satellite imaged the noctilucent clouds as far south as Northern Europe on May 25. Not long after, they were seen in the sky by people living in that region.The unusually southern appearance of these clouds is a clear sign that part of our atmosphere is changing, but scientists do not currently know how, why or what this means. The movement of the clouds suggests a global climate change in the lower atmosphere.
LiveScience June 28, 2007
The photo above shows one of the first ground sightings of these strange clouds, captured over Budapest, Hungary on June 15, 2007.
No one knows yet exactly how the clouds form, or what their formation says about the state of our atmosphere. Researchers plan to record two complete cloud seasons over both the Northern and Southern hemisphere, in the hopes of being able to provide an answer.
It is possible that the unusual movement of these clouds is one among many early warning signs of global climate change. If so, the fact that people are seeing these clouds, however beautiful they may be, could potentially herald disastrous problems further down the road.