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Noctilucent clouds

Wangler

Master Poster
Wangler
Joined
Feb 20, 2008
Messages
2,228
Beautiful display of noctilucent clouds above my hometown last night.

These typically only appear at latitudes above 50 degrees, but they have been getting lower and lower (I'm at 42 degrees N).

No record of these clouds before 1885, so they are a recent phenomenon.

Some speculate that climate change may be part of the factor in their appearing with increasing frequency.

They are really beautiful to the eye, they look like they are made of glowing neon.

 
I take it the phenomenon is explained by high clouds catching the setting suns light, only at far northern latitudes the sun never sets. So there is no reason the clouds were never seen 'so far south before' except maybe the clouds are higher? Or the sun is reflecting off of open ocean?
 
Or maybe like the WWII sub captain who saw an enemy convoy lined up in the sky? The convoy was 20 miles away, or twice as far as the horizon. I don't know the phenom involved, but I guess it is possible to 'see' light over the horizon.
 
casebro said:
I take it the phenomenon is explained by high clouds catching the setting suns light, only at far northern latitudes the sun never sets. So there is no reason the clouds were never seen 'so far south before' except maybe the clouds are higher? Or the sun is reflecting off of open ocean?
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The clouds must be at a certain high altitude, and the sunlight has to be at just the right angle, and there must be a specific content of water in the clouds...

Wangler, nobody hacked your drive. I checked, and the shot was a different example, though similar. :)
 
Wangler, you are very lucky to have spotted these clouds. I read at space weather that for the very first time they were spotted at relatively low latitudes and to watch out for them the following evening. I looked but didn't find any. A friend of mine who lives on the Oregon coast caught some about a year ago. I find them fascinating and really want to see them some day. I think one theory is that particles from space travel are seeding these clouds. One thing is for sure: they are becoming more common for whatever reason.
 
Wangler said:
It's a pretty sure bet that anything "live" is a recent phenomenon.
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And it's a pretty sure bet that any cloud you see is less than a week old, and any sunlight you see illuminating it is less than a day old.
 
portlandatheist said:
I think one theory is that particles from space travel are seeding these clouds.
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The liquid H2/O2 based rockets, such as the space shuttle main engine also dump water vapour in the higher layers of the atmosphere. I'm not sure if the amounts are significant enough, though.
 
Theory of Noctilucent Clouds
Mesopause is one of the most difficult locations in Earth's atmosphere to observe. Satellites, lidars, and radars, for example, can be used to do remote sensing measurements, but In situ measurements can only be carried out using expensive rockets. Remote sensing methods cannot provide direct measurements, and a rocket provide data with very limited spatial or temporal resolution (they penetrate the thin NLC layer with high speed in a few seconds, and only in two highly localized points, once on their way up and once on their way down).
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Kind of interesting we can determine the composition of distant stars by their spectrographic pattern but no one is sure whether noctilucent clouds are dust or ice.
 
portlandatheist said:
Wangler, you are very lucky to have spotted these clouds. I read at space weather that for the very first time they were spotted at relatively low latitudes and to watch out for them the following evening. I looked but didn't find any. A friend of mine who lives on the Oregon coast caught some about a year ago. I find them fascinating and really want to see them some day. I think one theory is that particles from space travel are seeding these clouds. One thing is for sure: they are becoming more common for whatever reason.
Click to expand...

I was very lucky...I have been looking for them on a regular basis, but this night my daughter saw them before I did....believe me, the pictures don't do them justice...they are magnificient.

I hope you can see them someday soon.
 
Had to post this up here


Picture97.jpg


http://www.dailymail.co.uk/sciencet...cloud-hovering-Earth-captured-astronauts.html

Unreal :boggled:
 
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