by neufer » Tue Aug 20, 2013 5:42 pm
http://www.universetoday.com/104239/the-highest-clouds-on-earth-shine-at-the-top-of-the-orbit/#ixzz2cX2LEEzX wrote:
Earth’s Highest Clouds Shine at the “Top of the Orbit”
by Jason Major, Universe Today, August 20, 2013
<<Looking for a new desktop background? This might do nicely:
a photo of noctilucent “night-shining” clouds seen above a midnight Sun over Alaska, taken from the ISS as it passed over the Aleutian Islands just after midnight local time on Sunday, August 4. When this photo was taken Space Station was at the “top of the orbit” — 51.6 ºN, the northernmost latitude that it reaches during its travels around the planet.
According to the NASA Earth Observatory site, “some astronauts say these wispy, iridescent clouds are the most beautiful phenomena they see from orbit.” So just what are they? Found about 83 km (51 miles) up, noctilucent clouds (also called polar mesospheric clouds, or PMCs) are the highest cloud formations in Earth’s atmosphere. They form when there is just enough water vapor present to freeze into ice crystals. The icy clouds are illuminated by the Sun when it’s just below the horizon, after darkness has fallen or just before sunrise, giving them their eponymous property. Noctilucent clouds have also been associated with rocket launches, space shuttle re-entries, and meteoroids, due to the added injection of water vapor and upper-atmospheric disturbances associated with each. Also, for some reason this year the clouds appeared a week early.>>
[quote=" http://www.universetoday.com/104239/the-highest-clouds-on-earth-shine-at-the-top-of-the-orbit/#ixzz2cX2LEEzX"]
[float=right][img3="[b][color=#0000FF][size=150]Noctilucent clouds (NLCs) drift over a midnight sunrise
above Alaska on August 4, 2013 (NASA)[/size][/color][/b]"]http://d1jqu7g1y74ds1.cloudfront.net/wp-content/uploads/2013/08/ISS036-E-028913_lrg-580x386.jpg[/img3][/float]Earth’s Highest Clouds Shine at the “Top of the Orbit”
by Jason Major, Universe Today, August 20, 2013
<<Looking for a new desktop background? This might do nicely: [url=http://d1jqu7g1y74ds1.cloudfront.net/wp-content/uploads/2013/08/ISS036-E-028913_lrg.jpg]a photo of noctilucent “night-shining” clouds[/url] seen above a midnight Sun over Alaska, taken from the ISS as it passed over the Aleutian Islands just after midnight local time on Sunday, August 4. When this photo was taken Space Station was at the “top of the orbit” — 51.6 ºN, the northernmost latitude that it reaches during its travels around the planet.
According to the NASA Earth Observatory site, “some astronauts say these wispy, iridescent clouds are the most beautiful phenomena they see from orbit.” So just what are they? Found about 83 km (51 miles) up, noctilucent clouds (also called polar mesospheric clouds, or PMCs) are the highest cloud formations in Earth’s atmosphere. They form when there is just enough water vapor present to freeze into ice crystals. The icy clouds are illuminated by the Sun when it’s just below the horizon, after darkness has fallen or just before sunrise, giving them their eponymous property. Noctilucent clouds have also been associated with rocket launches, space shuttle re-entries, and meteoroids, due to the added injection of water vapor and upper-atmospheric disturbances associated with each. Also, for some reason this year the clouds appeared a week early.>>[/quote]