Noctilucent Clouds

[acidohm]

Boreal season is well underway, decent displays have been photographed in Paris and further south.

watchers.news/2021/06/22/nlc-major-outbreak-europe-june-2021/

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[acidohm]

Italy, low latitude for such a significant display!

[wheels59]

There was a brilliant display of Noctilucent clouds over Elgin in Morayshire Scotland early hours of Thursday morning this week. My son who works a late shift and finishes at 2am took some great photos and sent them to me via farcebook messenger. Me being an old ludite and IT illiterate can't quite work out how to post them yet, I'll have a word with him to see how to do it and as soon as I'm able I'll post them! 

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[wheels59]

I think I've done it.
Sorry Acid I've realised after that you had already started this thread earlier.

[acidohm]

Jul 17, 2021 21:20:15 GMT wheels59 said:

I think I've done it.
Sorry Acid I've realised after that you had already started this thread earlier.

That's OK Wheelie 😊

Great pics, I haven't seen any this year but I'm glad others are getting the chance!

[nonentropic]

They are stunning.

So what do they mean?

are they an artifact of digital photography iso ranges above 10,000 make this stuff possible film was sort of 400s the limit to us plods.

is it an indicator of CO2 doing something to the polar atmosphere, just checking!

Is this a solar cycle thing and an indicator of weak solar magnetism. as per Don Easterbrook.

is this in the bible are some book!! Prophets etc.

[acidohm]

Jul 18, 2021 5:36:59 GMT nonentropic said:

They are stunning.

So what do they mean?

are they an artifact of digital photography iso ranges above 10,000 make this stuff possible film was sort of 400s the limit to us plods.

is it an indicator of CO2 doing something to the polar atmosphere, just checking!

Is this a solar cycle thing and an indicator of weak solar magnetism. as per Don Easterbrook.

is this in the bible are some book!! Prophets etc.

Truth is we really don't know....

As far as I've seen there are no records of these even during past low solar periods.

They are very visible with your own eyes, and yes, also photograph well.

They are the result of water vapuor condensing on meteorite dust in the upper mesosphere, hence as the sun falls below the horizon They are the last portion of the sky to be able to reflect light and so visible after or before sunset, sunrise by about an hour or more.

Why this phenomena occurs now is not understood.

Did our ancestors see them but not appreciate them, were They asleep after sunset, were They not there till now....no one seems to know.



This at least gives an idea of spread, although good pictures have been taken in Paris and Italy (see other thread) so last night isn't a widespread event compared to others this season.

[blustnmtn]

Mars is apparently the source of the dust!

“The Martian dust cloud is kept within the inner Solar System by Jupiter’s gravitational influence, and it ends at Earth because our planet’s gravity sucks up all the dust that gets near it. “That’s the dust we see as zodiacal light,” said Jørgensen.

Measuring the distribution of this dust cloud, the researchers found that it’s consistent with the variation of zodiacal light that has been observed from Earth.

It’s easy to see under certain conditions—and easiest at this time of year.”

www.forbes.com/sites/jamiecartereurope/2021/03/12/martian-light-how-a-nasa-spacecraft-solved-the-mystery-of-cosmic-dust-and-how-to-see-it-with-your-naked-eyes/?sh=33cdaafa408a

[wheels59]

Apparently they were seen over Israel recently as well

[nonentropic]

is it dust or WV or generated by dust??

[blustnmtn]

Jul 18, 2021 19:50:13 GMT nonentropic said:

is it dust or WV or generated by dust??

This is from the Wikipedia article:

“Data from the Aeronomy of Ice in the Mesosphere satellite suggests that noctilucent clouds require water vapour, dust, and very cold temperatures to form.[8] The sources of both the dust and the water vapour in the upper atmosphere are not known with certainty. The dust is believed to come from micrometeors, although particulates from volcanoes and dust from the troposphere are also possibilities. The moisture could be lifted through gaps in the tropopause, as well as forming from the reaction of methane with hydroxyl radicals in the stratosphere.”

[acidohm]

Jul 18, 2021 19:50:13 GMT nonentropic said:

is it dust or WV or generated by dust??

Every drop of condensed water in our atmosphere has formed around a dust particle, no dust, no clouds.

www.weather.gov/source/zhu/ZHU_Training_Page/clouds/cloud_development/clouds.htm#:~:text=The%20water%20vapor%20content%20of,not%20all%20dusts%20will%20do.

[missouriboy]

Jul 18, 2021 19:56:41 GMT blustnmtn said:

Jul 18, 2021 19:50:13 GMT nonentropic said:

is it dust or WV or generated by dust??

This is from the Wikipedia article:

“Data from the Aeronomy of Ice in the Mesosphere satellite suggests that noctilucent clouds require water vapour, dust, and very cold temperatures to form.[8] The sources of both the dust and the water vapour in the upper atmosphere are not known with certainty. The dust is believed to come from micrometeors, although particulates from volcanoes and dust from the troposphere are also possibilities. The moisture could be lifted through gaps in the tropopause, as well as forming from the reaction of methane with hydroxyl radicals in the stratosphere.”

Are they related to BLM radicals?

[blustnmtn]

Reviving this topic:

spaceweatherarchive.com/2022/01/26/an-outburst-of-noctilucent-clouds/

[acidohm]

Jan 27, 2022 17:48:55 GMT blustnmtn said:

Reviving this topic:

spaceweatherarchive.com/2022/01/26/an-outburst-of-noctilucent-clouds/

It's quite a seasonal topic for us Boreal types....and there's vert little habitated land in places NLC can be viewed in the south.