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jokergirl
2008-Jul-10, 10:30 AM
We get them here a lot seeing as we're far north. They're not rare nor special and the mechanism that makes them visible to us (sun below the horizon->darkish sky, illuminated clouds) are quite well explained.

So what's the deal with articles popping up now and then saying how they are a "mystery"? Spaceweather did it recently. I agree that they are forming very high and we are not yet entirely sure how. Is that all there is to it? And if so, what can we still learn by looking at them from the ground that hasn't already been documented?

;)

hhEb09'1
2008-Jul-10, 01:13 PM
Spaceweather did it recently. Do you have a link to their article handy? I'm interested.

LotusExcelle
2008-Jul-10, 01:17 PM
http://www.atoptics.co.uk
http://www.atoptics.co.uk/highsky/nlc2.htm
http://www.atoptics.co.uk/hat1.htm

Invaluable and gorgeous site for all your sky optics needs.

Jens
2008-Jul-10, 03:17 PM
So what's the deal with articles popping up now and then saying how they are a "mystery"?

I can't claim to be an expert, but my understanding is that the mystery is that they have increased a lot in recent years. I remember reading somewhere that 100 years ago, they were very rare, but they have become more common.

jokergirl
2008-Jul-10, 04:42 PM
Hm, I don't have the previous article but their main site has a blurb right now saying


NOCTILUCENT VERMONT: So far this year, noctilucent clouds have been sighted mainly over Europe, with a smattering over Canada (http://spaceweather.com/submissions/large_image_popup.php?image_name=Bruce-McCurdy-bright-quilt_1215111277.jpg), and none over the USA--make that almost none: "Last night (6 July 2008) while flying from Chicago to Vermont, I observed some noctilucent clouds about 300 miles west of Burlington," reports veteran sky watcher Jan Curtis. "It was a small patch extending 10o to 15o above the horizon. Too bad I couldn't get to my camera!" Readers living in northern-tier US states, it is time to join the hunt for NLCs; observing tips may be found in the photo gallery (http://spaceweather.com/nlcs/gallery2008_page9.htm?PHPSESSID=n7atsp1dsjuc27bns1 vc7c06k3).

I'm not quite sure about this, but might it be that the observations, not the clouds themselves, have increased? People are generally more aware of what goes on in the skies these days, and optics are becoming better as well.

;)

Edit: HERE (http://science.nasa.gov/headlines/y2003/19feb_nlc.htm)'s an article from science@nasa which claims they were first observed after Krakatoa.

Jens
2008-Jul-11, 01:37 AM
I'm not quite sure about this, but might it be that the observations, not the clouds themselves, have increased? People are generally more aware of what goes on in the skies these days, and optics are becoming better as well.


I don't know, have they? It's certainly true that there are more people in the world today, and maybe more people who are interested in astronomy as a hobby, but on the other hand, there is a lot more street lighting and urbanization, so fewer people are actually able to observe. Plus, I doubt that better optics would have much to do with observing noctilucent clouds. Would they?



;)


:confused: Did I say something funny?

jokergirl
2008-Jul-11, 07:39 AM
No, ;) is my usual signature on most of my posts. Being a joker-girl and all.

;)