APOD: Mysterious Green Patches on the Sky (2013 Sep 30)

[Beyond]

MIce have withers?

Obviously a glitch in the matrix.

Neo will take care of it.

[Chris Peterson]

Me, I am going with, there was something in the meteors, This year I have noticed more than a few meteors with a greenish burn. Enough small particles left from a burned out meteor shower could have been the cause. What turns green when burned?

The green commonly observed in bright meteors is caused by ionized atmospheric oxygen. It has a very short lifetime. There is nothing in meteors that could cause a persistent green atmospheric phenomenon.

[Nitpicker]

Me, I am going with, there was something in the meteors, This year I have noticed more than a few meteors with a greenish burn. Enough small particles left from a burned out meteor shower could have been the cause. What turns green when burned?

The green commonly observed in bright meteors is caused by ionized atmospheric oxygen. It has a very short lifetime. There is nothing in meteors that could cause a persistent green atmospheric phenomenon.

These elements have greenish components in a flame test: Copper, Boron, Manganese, Molybdenum, Phosphorus, Antimony, Tellurium, Thallium. Possibly others.

As for meteors, I defer to Chris' authority on the matter.

[Ann]

My two cents go here. Before and during the appearance of the green clouds, the sky is very orange, unnaturally so, in my opinion. Could it be that for some reason, the color balance of the camera is off? When the clouds appear they are a different color than the sky, and the camera responds by showing the clouds as green, while the sky still looks very orange.

Those were my two cents. I'm probably wrong.

Ann

[Chris Peterson]

My two cents go here. Before and during the appearance of the green clouds, the sky is very orange, unnaturally so, in my opinion. Could it be that for some reason, the color balance of the camera is off? When the clouds appear they are a different color than the sky, and the camera responds by showing the clouds as green, while the sky still looks very orange.

Those were my two cents. I'm probably wrong.

I think you are correct. One reason I don't have a strong opinion on what we are seeing is that the color seems completely wrong, and doesn't even seem consistent between all the frames. It's as if auto white balance is in place, which seldom works well with these kinds of nighttime images.

[alter-ego]

My two cents go here. Before and during the appearance of the green clouds, the sky is very orange, unnaturally so, in my opinion. Could it be that for some reason, the color balance of the camera is off? When the clouds appear they are a different color than the sky, and the camera responds by showing the clouds as green, while the sky still looks very orange.

Those were my two cents. I'm probably wrong.

I think you are correct. One reason I don't have a strong opinion on what we are seeing is that the color seems completely wrong, and doesn't even seem consistent between all the frames. It's as if auto white balance is in place, which seldom works well with these kinds of nighttime images.

I too have been really bothered by the color imbalance, and have not given much value to the image colors. I would have written off the green formations as clouds too if not for the obvious opaque clouds that enter the scene at the end. The cloud color there is more like the background orange. I don't have a good reason to pick green for one set and orange for another unless the green formations really have a (substantial) green component. To me, green is about the only color that comes across a realistic (e.g. the trees). I tend to still believe that the green formations originate from a real source and not just an artifact of CCD response only against a hazy-dark sky.

With that said, I don't understand the behavior of CCD response at low light levels especially if an automatic color balance or other settings are active. Maybe if the affect was camera setting related, it might be reproducible.

[Kevin Snair]

Good morning, again, I am the photographer who crated this video.

To address questions about the white balance, I would agree that the color is off (a tad too warm). Photographing in very low light at extremely sensitive ISOs tends to cause difficulty in color accuracy. I don't in any way argue that the colors were actually that intense. What I can say is my white balance (along with all the other settings) were set at a consistent value throughout the shoot. Was the "green fog" that green ...... I don't know as it was not visible to the naked eye. I do point out that the anomaly is relatively consistent throughout the time that it appears and is distinctly different from anything else happening in the sky that evening (from my observations). I still have no theory as to what the video is showing ...... natural phenomenon or error on my part. Perhaps we will never know but I appreciate the time and thought that everyone is contributing to help get to the bottom of this.

[neufer]

Click to play embedded YouTube video.

Withers... The ridge between the shoulder bones, at the base of the neck.

Who would know more about Withers, than Josephine The Plumber, played by Jane Withers.

Jane's Withers came in handy when she had to haul around the really big can of Comet.

I think someone already suggested that the green patches might be the aftermath of a comet.

[gcallahan]

Here are links to two stills. One is prior to the arrival of the green. The other during.

Http://www.creativeimagery.ca/Persieds_367.jpg
Http://www.creativeimagery.ca/Persieds_424.jpg

Thanks, Kevin, these stills really help. I setup my browser so I could quickly switch back and forth between these two, at 100% zoom, both positioned identically so that I could compare any given part of the image. When I focused on the rocks at the left, I noticed that the green increased there just like it did in the clouds. This leads me to believe that the green is not caused by anything in the clouds, and it's not aurora or airglow within the field of view (because they wouldn't be between the camera and the rocks). That leaves two likely causes: either the light source is changing, or the recording system (camera plus post-processing) is changing.

It seems most likely to me that it's simply the post-processing that is amplifying the green. When the camera is set to high sensitivity and over saturation, small variation get amplified.

It also seems possible to me that a green aurora appeared behind the camera (the camera was facing south east, and aurora show strongest to the north in the northern hemisphere). The aurora could cast some light that reflected off clouds and rocks, too dimly to be noticed by the human eye, but could be picked up by a camera set to high sensitivity and long exposure.

Sound reasonable?

[Rod]

As I mentioned in an earlier post, the green actually does appear earlier in the film, and I was interested to see that it appeared in both of the two photos uploaded. In Persieds_367.jpg (sic), a very small and faint green area occurs in the area outlined by 950px to 1105px x axis and 70px to 150px y axis (origin at top left), assuming I'm reading the GIMP correctly. Watching the video, this also appears the origin later of the artifact in question and is actually the most intense part of the second photo.

Also, in the same photo, note the green on the "beach" to the right (1640px to 1960px x axis, 1420px to 1500px y axis). Unless there is moss or algae there, that is not right.

Definitely false coloration, either from the Park lights or the camera's auto-correction. Converting to greyscale ends up with nothing showing at all in the sky, even when increasing contrast to ridiculous levels. On the second photo, doing the same procedure shows a cloud like formation.

I also noticed with greyscale and again, extreme contrast, the remote light source (some city?) is even more powerful than I had originally thought, even apparently reflecting off the upthrust/rock/whatever (the one with trees in the middle).

I'm actually thinking what we have is a reflection off clouds/fog from the remote light source.

Rod

[glenna]

aurora

[sexyrexy]

I agree with many posts here, it is optics in the camera and lens, the lens and receiver bounce back some light and color from the incoming tide resulting in the effect, or it could all be mass hypnosis, I didnt see the patches on the first viewing,lol

[Featheredflyer]

Possibly the Flash of green one sees at the setting of the sun. In this case it was reflected off the clouds.

[mjimih]

to me it behaves (moves) like an Aurora, a weak unusual one though.

[gordie]

Hi. Looks like the green flash of the setting sun projected on low clouds to the east. Azimuth of movement is correct, and if the last few frames were taken late in the day
just before sunset, the green flash could fit. G

[MichaelObrien]

I believe it's green flash, -- see: < http://en.wikipedia.org/wiki/Green_flash > -- (and not camera peculiarities), shining onto high thin clouds, which are moving right to left, but I'm not so sure it's the sunset that's responsible for it.

The short film begins at dusk, to film the meteor shower, and watches all night as the galaxy slowly moves left to right, and near the end of the night -- (i.e. *approaching sunrise*) -- we get the much discussed phenomenon in the sky, so I doubt there's much of a westerly view in the scene.

As for background lighting, I dont think any light sources in the photographed vicinity was responsible. The phenomenon is illuminated by something projecting onto a wide area, at considerable altitude, hence - from a great distance - and apparently from a shallow angle, (from over the horizon?), (giving rise to the contrast seen amid the illumination, resulting from the uneven distribution of the high thin cloud.

[owlice]

The filming ended about 3 AM. A green flash does not seem likely IMO at that hour, especially one that persists throughout the time the green color is apparent.

[MichaelObrien]

After plenty of review and consideration, I now believe it is caused by aurora, possibly illuminating some high thin clouds.

Maybe it's another example of noctilucent clouds.

See: < http://www.space.com/21498-electric-blu ... video.html >

[RPJE Olsen]

The light source behind the rock pinnacle on the left is reflected off the green trees and the tidal water into the lens.

[Didymus]

The tide encroaches.
Its foam bubles burst.
A mist rises in the gentle draft.
We behold the glaring cone.
A fog lit green is all it may be.

[Anortham@mymts.net]

Could that phenomena be the temporal zone (Cancer) equivalent of the Equatorial Zone "Green Flash"? It could be longer duration but much less intense due to axial tilt.

Wonderful photos (ALL of them) I had to go to the Cambridge server during the U.S. Govt temper tantrum.

Regards
A.S. Northam
285 Wales Avenue
Winnipeg Mb Canada
R2M 2S8
(204) 257-6162

[inelukimeya@hotmail]

Hello,

I agree with Anortham@mymts.net - and many others
It is similar to aurora as an emission of light from excited hydrogen atoms.
This phenomenon is well known and is called an airglow: http://en.wikipedia.org/wiki/Airglow
You can also consult this link (sorry it's in french) as seen August the 7th at the pic du midi in France:
http://romain-montaigut.fr/time-lapses/ ... ic-du-midi

Regards,
Xavier

[BigSkyCountry]

The green glow coincides with the rising tide in the Bay Of Fundy, the largest on Earth, in terms of height. The height change is 50 feet and the mass change is 5.3 million tons per second (115 billion tons per 6 hour tide). This is 1/100th of the mass of hydrogen burned by the Sun per second, 600 million tons.

The Bay Of Fundy is about the same area and shape as nearby Massachusetts. Imagine if that entire state rose 50 feet in 6 hours. And all that water probably comes from the Labrador Current, which is cold water from melting ice in Greenland, Canada and the Arctic, which hugs the Canadian coast on it's southerly jaunt to where the Titanic rests.

Being August 11th, still a warm Summer, I suspect this tide creates an air temperature and pressure change in the column of air above the bay, which affects dew point, so clouds formed. These clouds reflected some terrestrial source of green light. These green clouds were obviously moving in a different direction that the higher cirrus clouds were moving, but that's entirely possible, according to balloonists and other time lapse videos I've seen.

It appears the camera was pointed south, so the green clouds were moving north by northeast. How can we check the weather for the evening of August 11th to verify this?

[Hichem]

i think it's an aurora

[rstevenson]

... the Labrador Current, which is cold water from melting ice in Greenland, Canada and the Arctic, which hugs the Canadian coast on it's southerly jaunt to where the Titanic rests.

Not quite. You're referring to the "cold wall", the southern part of the Labrador Current. It does hug the coast, as you say, and therefore doesn't come near where the Titanic sank, which is about 1200 km east of Nova Scotia, closer to the warmer currents running northeastward at that point.

Rob