APOD: Noctilucent Clouds, Reflections, and... (2019 Jun 26)

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APOD: Noctilucent Clouds, Reflections, and... (2019 Jun 26)

Post by APOD Robot » Wed Jun 26, 2019 4:08 am

Image Noctilucent Clouds, Reflections, and Silhouettes

Explanation: Sometimes it's night on the ground but day in the air. As the Earth rotates to eclipse the Sun, sunset rises up from the ground. Therefore, at sunset on the ground, sunlight still shines on clouds above. Under usual circumstances, a pretty sunset might be visible, but unusual noctilucent clouds float so high up they can be seen well after dark. Normally too dim to be seen, they may become visible just after sunset during the summer when illuminated by sunlight from below. Noctilucent clouds are the highest clouds known and thought to be part of polar mesospheric clouds. Featured here as they appeared two weeks ago, a network of noctilucent clouds was captured not only in the distant sky but in reflection from a small lake just north of Zwolle, Netherlands, with trees in stark silhouette across the horizon. Unusually bright noctilucent clouds continue to appear over much of northern Europe. Much about noctilucent clouds has been discovered only over the past decade, while how they form and evolve remains a topic of active research.

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Re: APOD: Noctilucent Clouds, Reflections, and... (2019 Jun 26)

Post by orin stepanek » Wed Jun 26, 2019 11:18 am

Stunningly Beautiful! Very well done photograph! :clap: :thumb_up:
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Re: APOD: Noctilucent Clouds, Reflections, and... (2019 Jun 26)

Post by BDanielMayfield » Wed Jun 26, 2019 2:05 pm

Yes the photo selected for today's APOD is very beautiful, but the cause of the increase in these noctilucent clouds and the implications thereof certainly aren't.

These are some speculative ideas, but this what might be is happening:
  • 1. Human activities increase the Earth's atmospheric CO2 level.
    2. The greenhouse gas CO2 gradually warms the planet.
    3. Warming polar areas begin to release trapped methane (CH4) as permafrost melts.
    4. How nice! The increase in atmospheric CH4 causes the increasing occurrence of those pretty noctilucent clouds. But ...
    5. CH4 is a much more potent greenhouse gas, so global warming accelerates.
    6. The global sea level rises at an accelerating rate.
Sorry to be looking at the dark side of these silvery lined clouds, but hey, it is what it is y'all.

Bruce
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Re: APOD: Noctilucent Clouds, Reflections, and... (2019 Jun 26)

Post by othermoons » Wed Jun 26, 2019 3:13 pm

Ouch! That's why space travel research is so important, how else are we going to best resolve the dilemma our planet is in. When we're attached to the surface for the most part its really hard to see the big picture.

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Re: APOD: Noctilucent Clouds, Reflections, and... (2019 Jun 26)

Post by Chris Peterson » Wed Jun 26, 2019 9:39 pm

BDanielMayfield wrote:
Wed Jun 26, 2019 2:05 pm
Yes the photo selected for today's APOD is very beautiful, but the cause of the increase in these noctilucent clouds and the implications thereof certainly aren't.

These are some speculative ideas, but this what might be is happening:
  • 1. Human activities increase the Earth's atmospheric CO2 level.
    2. The greenhouse gas CO2 gradually warms the planet.
    3. Warming polar areas begin to release trapped methane (CH4) as permafrost melts.
    4. How nice! The increase in atmospheric CH4 causes the increasing occurrence of those pretty noctilucent clouds. But ...
    5. CH4 is a much more potent greenhouse gas, so global warming accelerates.
    6. The global sea level rises at an accelerating rate.
Sorry to be looking at the dark side of these silvery lined clouds, but hey, it is what it is y'all.
Noctilucent clouds consist of ice which grows on meteoritic dust. This occurs high in the mesosphere, and requires extreme cold. Curiously, global warming results in colder temperatures in the polar and subpolar mesosphere. So yeah, global warming plausibly explains the apparent increase in noctilucent cloud frequency, seasonal duration, and latitude of occurrence.
Chris

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Re: APOD: Noctilucent Clouds, Reflections, and... (2019 Jun 26)

Post by BDanielMayfield » Wed Jun 26, 2019 9:49 pm

Did I put a huge downer on the will to post comments today? Not my intention, if so. The selection this APOD was an excellent choice IMO.

And hey guys, look on the bright side like I always do. AFTER the continental ice sheets collapse and all coastal areas get flushed the Earth will rebound. (It's a very resilient planet.) CH4 in the atmosphere will peak at some point and then diminish as it is broken down by sunlight into CO2 and H2O. The biosphere will then scrub the excess CO2 out (another Carboniferous Age, perhaps?).

Bruce, long term optimist

P.S. Thanks for the comment on my first post Chris.
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Re: APOD: Noctilucent Clouds, Reflections, and... (2019 Jun 26)

Post by Chris Peterson » Wed Jun 26, 2019 11:00 pm

BDanielMayfield wrote:
Wed Jun 26, 2019 9:49 pm
And hey guys, look on the bright side like I always do. AFTER the continental ice sheets collapse and all coastal areas get flushed the Earth will rebound.
And think how much better it will do without us around to mess things up!
Chris

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Re: APOD: Noctilucent Clouds, Reflections, and... (2019 Jun 26)

Post by BDanielMayfield » Thu Jun 27, 2019 12:18 am

Chris Peterson wrote:
Wed Jun 26, 2019 11:00 pm
BDanielMayfield wrote:
Wed Jun 26, 2019 9:49 pm
And hey guys, look on the bright side like I always do. AFTER the continental ice sheets collapse and all coastal areas get flushed the Earth will rebound.
And think how much better it will do without us around to mess things up!
Seems to be a requirement for the biosphere to fix things.
"Happy are the peaceable ... "

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Re: APOD: Noctilucent Clouds, Reflections, and... (2019 Jun 26)

Post by neufer » Thu Jun 27, 2019 3:26 am

BDanielMayfield wrote:
Wed Jun 26, 2019 9:49 pm

And hey guys, look on the bright side like I always do. AFTER the continental ice sheets collapse and all coastal areas get flushed the Earth will rebound. (It's a very resilient planet.) CH4 in the atmosphere will peak at some point and then diminish as it is broken down by sunlight into CO2 and H2O. The biosphere will then scrub the excess CO2 out (another Carboniferous Age, perhaps?).
Not to mention the CH4, CO2 and H2O :!:
Art Neuendorffer

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Re: APOD: Noctilucent Clouds, Reflections, and... (2019 Jun 26)

Post by orin stepanek » Thu Jun 27, 2019 11:48 am

You hear it both ways! https://www.nasa.gov/feature/goddard/na ... han-losses Nobody seems to know for sure! One thing; as long as the population increases there will probably be a warming trend! We are consumers of carbon fuel! You ever notice that it's warmer in cities than in the country! I don't have the solution! :shock:
Orin

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Re: APOD: Noctilucent Clouds, Reflections, and... (2019 Jun 26)

Post by Chris Peterson » Thu Jun 27, 2019 12:47 pm

orin stepanek wrote:
Thu Jun 27, 2019 11:48 am
You hear it both ways!
It is both ways. Global warming refers to the total temperature rise of the Earth's atmosphere and oceans caused by the radiative imbalance created by increasing greenhouse gases. Global warming drives changes in climate, which means regionally we can see wetter or drier, warmer or cooler.

Global warming is easily understood. Climate change is very tricky to model.
Chris

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Re: APOD: Noctilucent Clouds, Reflections, and... (2019 Jun 26)

Post by BDanielMayfield » Thu Jun 27, 2019 1:16 pm

orin stepanek wrote:
Thu Jun 27, 2019 11:48 am
You hear it both ways! https://www.nasa.gov/feature/goddard/na ... han-losses Nobody seems to know for sure! One thing; as long as the population increases there will probably be a warming trend! We are consumers of carbon fuel! You ever notice that it's warmer in cities than in the country! I don't have the solution! :shock:
Nice, balancing comment Orin. Antarctica to the rescue, perhaps? The Earth is resilient as I stated before. But Greenland's ice sheet is taking a beating.

Bruce
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Re: APOD: Noctilucent Clouds, Reflections, and... (2019 Jun 26)

Post by orin stepanek » Thu Jun 27, 2019 4:30 pm

BDanielMayfield wrote:
Thu Jun 27, 2019 1:16 pm
orin stepanek wrote:
Thu Jun 27, 2019 11:48 am
You hear it both ways! https://www.nasa.gov/feature/goddard/na ... han-losses Nobody seems to know for sure! One thing; as long as the population increases there will probably be a warming trend! We are consumers of carbon fuel! You ever notice that it's warmer in cities than in the country! I don't have the solution! :shock:
Nice, balancing comment Orin. Antarctica to the rescue, perhaps? The Earth is resilient as I stated before. But Greenland's ice sheet is taking a beating.

Bruce
It's a tough situation; that's for sure! No easy answer! :bang:
Orin

Smile today; tomorrow's another day!