- Posted July 7, 2012 by
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This iReport is part of an assignment:
Light Years: Your view of space and stars
When summer night skies light up (noctilucent cloud)
- Jareen, CNN iReport producer
Noctilucent cloud (Night-shining cloud - NLC) is the highest cloud in Earth's atmosphere and it is one of the most amazing shows on Earth only mother nature can create. These clouds are visible during summer nights, in the latitudes approximately 45-65 degrees. All you need is Noctilucent cloud present, clear night and look towards north about an hour and a half, two hours after sunset and the same time before sunrise.
The clouds are about 80 km (50miles) above the Earth and are illuminated by the sun that is bellow the horizont. The clouds are silvery white, almost electric blue. They get commonly mistaken with cirrus clouds, but when you'll see NLC you will be able to tell the difference between them. The season usually starts in the beginning/mid month of May and lasts until end of August. The peak for NLC season is in mid July, so you can expect the best displays around this time.
Even though NLCs are very rare, their sightings have been on the increase in recent years. They were only discovered in 1880's, and there is no positive records that they existed before this time. They are not only one of the newest clouds in the atmosphere, but are also the least understood and many qustions and mysteries elude them. The clouds consist of ice particles that are in very thin sheets, forming in a very dry, clear and very cold atmospheric conditions. Because of the structure of atmosphere they can not be transported from the Earth surface to the mesosphere where they occur. Popular hypothesis is that the water in ice particles in Noctilucent clouds comes from cometary water. As there have been positive sightings linked to rocket and satellite launches another theory is that the water in ice particles comes from the constituent elements of the space shuttle fumes which consist mostly of water.
I have seen them for the first time three years ago and I got hooked straight away. I can count on two hands how many times I have witnessed the Noctilucent cloud, but every time it is a breathtaking show.