Why noctilucent clouds on the increase?

[newtonian]

This came up recently when questioning the cause of the recent shuttle disaster- some thought it may have been contributed to by the increase in noctilucent cloud formation.<br /><br />Does anyone know why these clouds have been on the increase recently?

 

[newtonian]

No takers? I?ll help by giving a link and a couple of excerpts from it:<br /><br />This is a space.com article:<br /><br />http://www.space.com/scienceastronomy/strange_clouds_030219.html<br /><br />Space Station Crew Photographs Mysterious Clouds that Shine at Night<br />By Tony Phillips<br />Science.NASA.gov<br />posted: 11:30 am ET<br />19 February 2003<br /><br />Two excerpts:<br /><br />"They hover on the edge of space. Thin, wispy clouds, glowing electric blue. Some scientists think they're seeded by space dust. Others suspect they're a telltale sign of global warming."<br /><br />"A NASA spacecraft scheduled for launch in 2006 should provide some answers. The Aeronomy of Ice in the Mesosphere satellite, or AIM for short, will orbit Earth at an altitude of 342 miles (550 kilometers). Although it's a small satellite, says Thomas, there are many sensors on board. AIM will take wide angle photos of NLCs, measure their temperatures and chemical abundances, monitor dusty aerosols, and count meteoroids raining down on Earth. "For the first time we'll be able to monitor all the crucial factors at once.""<br /><br />The article showed that the huge Krakatoa volcanic eruption in 1883 caused the first observation of Noctilucent clouds in 1885 - apparently never observed before that!<br /><br />However, no such eruption is causing the present increase in observations of Noctilucent clouds.<br /><br />So, what is causing it? Global warming? Or perhaps entry into a galactic cloud by our solar system with increased deposition of galactic (or intergalactic) matter into earth?s upper atmosphere?<br /><br />Anyone?

 

[newtonian]

Still no takers?<br /><br />Here is some more help at this original source:<br /><br />http://science.nasa.gov/headlines/y2003/19feb_nlc.htm<br /><br />This contains beautiful pictures of Noctilucent clouds, and an informative diagram.<br /><br />Here are two excerpts:<br /><br />"Eventually the ash settled [from 1883 Krakatoa eruption] and the vivid sunsets of Krakatoa faded. Yet the noctilucent clouds remained. "It's puzzling," says Thomas. "Noctilucent clouds have not only persisted, but also spread." A century ago the clouds were confined to latitudes above 50[degrees]; you had to go to places like Scandinavia, Russia and Britain to see them. In recent years they have been sighted as far south as Utah and Colorado."<br /><br />"Ordinary clouds, which are close to Earth, get their dust from sources like desert wind storms. It's hard to waft wind-blown dust all the way up to the mesosphere, however. "Krakatoa may have seeded the mesosphere with dust in 1883, but that doesn't explain the clouds we see now," notes Thomas. "Perhaps the source is space itself," he speculates. Every day Earth sweeps up tons of meteoroids--tiny bits of debris from comets and asteroids. Most are just the right size to seed noctilucent clouds."<br /><br />The obvious problem is that earth is always seeded with tiny meteorites, yet earth has not always had this frequent noctilucent clouds.<br /><br />Again I ask:<br /><br />Could this be due to or connected with global warming?<br /><br />Could we be passing through a galactic zone with more dust than usual?

 

[newtonian]

72 views and still no takers? Here is a little more help:<br /><br />From: http://www.daviddarling.info/encyclopedia/N/noctilucent_clouds.html<br /><br />"noctilucent clouds (NLCs)<br />Complex interwoven streaks or knots of cloud, generally white or pearly-blue in color, sometimes with a golden lower edge, best seen from latitudes 50 to 60° during the deep twilight of summer with the Sun 6 to 16° below the horizon. Although not completely understood, they are believed to result from water vapor condensing on small particles (possibly volcanic or meteoritic debris) at an altitude of about 82 km. Although superficially resembling cirrus clouds, NLCs form close to the mesopause - far above the tropopause, to which ordinary clouds are confined - and are distinguishable by their delicate herring-bone structure. "<br />Notice that the source of the dust particles for the core of water condensation is noted to be either volcanic or meteoric.<br /><br />There is no volcanic source scientists have discovered.<br /><br />How about meteoric????<br />

 

[arc2]

Actually, you just need to get the right guy interested. I am interested and will, in fact, call attention to this information and see what my friends have to say.<br /><br />The problem with declaring an increase in detection of a poorly documented phenomenon whose source we know nothing about is that we have no previous activity to judge against. We can't say that it is increasing if we just don't know.<br /><br />I am curious about the phenomenon, though. <br /><br />

 

[newtonian]

arc2 - Sorry, I missed your response!<br /><br />Yes, I am more than curious myself!<br /><br />Have your friends come to any conclusion?<br /><br />You all - can you help answer this question?

 

[jmilsom]

Seems like a subject that we (humanity) don’t know too much about yet. The obvious answer that leaps to mind is that is would be a man-made phenomenon linked to the industrial age. We’re not only pumping Co2 into the atmosphere but all sort s of pollutants and particulates on a scale never seen before. Perhaps we are in for yet another rude shock (as with CFCs and ozone). The Krakatoa eruption was perhaps powerful enough to shoot a lot of material very high into the atmosphere. <br /><br />It seems we also do not know yet whether having more noctilucent clouds is a good thing or a bad thing. It is impressive that we have to foresight to shoot up a satellite to learn more! <br /> <div class="Discussion_UserSignature"> </div>

 

[newtonian]

jmilsom - Thank you for your response.<br /><br />Yes, pollution can cause beautiful sunsets. Why not also beautiful noctilucent clouds!<br /><br />In that case, it is both a good and a bad thing.<br /><br />Whatever the cause, my concern is that it may be a warning of danger.<br /><br />Like red sky in morning, sailors take warning.<br /><br />Another possible cause, an increase in stardust, may indicate we are entering an interstellar dust and gas cloud - though I would think there would be other observations to confirm something like that.

 

[newtonian]

crazyeddie - Thank you for your thought provoking response.<br /><br />The problem with eliminating all possible causes for an observation is that all observations have a cause, i.e. cause and effect.<br /><br />That means we need to consider all possibilities, including some that we might intuitively discount.<br /><br />I'll try another one: earth's magnetic field plus other magnetic fields, such as the solar magnetic field.<br /><br />Your comment about most pollutants not making it at that high an altitude gave me the clue.<br /><br />I remember reading a good article somewhere about how various atoms are escaping earth, or nearly escaping earth, at high speed near the poles - I believe it had something to do with earth's magnetic field.<br /><br />The problem with this as a cause is that earth's magnetic field is weakening lately - there still could be a connection between the two observations.<br /><br /><br />However, my memory is not sufficient - I will need to research it and post again.<br /><br />Feel free to beat me to it.<br /><br />You all - Ditto!

 

[newtonian]

Ok - I am on a newtonian brainstorm due to trying to determine the correct model for the Noachian flood, and earth's overall accretion of water.<br /><br />Could this be evidence of a process, not uniform, whereby earth has accreted its water????

 

[newtonian]

crazyeddie - Simple:<br /><br />If Noctilucent clouds are on the increase because of increasing accretion of dust and water from space, then this would be evidence of a non-uniform rate of accretion over time.<br /><br />How do you think earth got its water?

 

[nevers]

You forgot - <br /><br />"Red skies at night, sailors delight"<br /><br />I think the problem of these so-called "noctilucent clouds" lies with increased air traffic. Somebody should call the Skyway Patrol...!

 

[newtonian]

Nevers - Hi! How are you?<br /><br />Have you seen Noctilucent clouds or Mother of Pearl clouds?<br /><br />Are you serious about the air traffic?

 

[nevers]

I see clouds, lots of clouds. No matter what their names are they should go away. Yes, I am cirrus...call the Skyway Patrol. Something needs to be done about this.<br /><br />Hey Paul - thanks for asking. Yes, I am doing fine...except for the cloud thing going on.