APOD: Dark Belt Reappearing on Jupiter (2010 Nov 29)

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Expand view Topic review: APOD: Dark Belt Reappearing on Jupiter (2010 Nov 29)

Re: APOD: Dark Belt Reappearing on Jupiter (2010 Nov 29)

by RADDAD » Fri Dec 03, 2010 6:07 pm

Chris, you mentioned cyclic but without regular periodicity. It would be interesting to know how often this phenomenon has occurred. Someone must be keeping recent records. I checked my old log and I saw a one-band Jupiter on January 18, 1990. I am not a regular observer - You get out of the habit living in Seattle!

Re: APOD: Dark Belt Reappearing on Jupiter (2010 Nov 29)

by dougettinger » Thu Dec 02, 2010 3:43 pm

Chris, thank you for this excellent discussion. Doug

Re: APOD: Dark Belt Reappearing on Jupiter (2010 Nov 29)

by Chris Peterson » Thu Dec 02, 2010 3:36 pm

dougettinger wrote:Perhaps there is an ammonia cycle on Jupiter like there is a water cycle on Earth. I believe that is what you are suggesting?
It's possible. I'm no expert on planetary atmospheres, or ammonia chemistry. The water cycle on Earth isn't a synthesis cycle, but a distribution cycle. I was suggesting that I'd expect an ammonia synthesis cycle on a gas giant; there's probably a distribution cycle, as well.

Re: APOD: Dark Belt Reappearing on Jupiter (2010 Nov 29)

by dougettinger » Thu Dec 02, 2010 2:52 pm

Perhaps there is an ammonia cycle on Jupiter like there is a water cycle on Earth. I believe that is what you are suggesting?

Doug Ettinger
Pittsburgh, PA

Re: APOD: Dark Belt Reappearing on Jupiter (2010 Nov 29)

by Chris Peterson » Wed Dec 01, 2010 8:34 pm

dougettinger wrote:Where did the high flying light colored ammonia clouds come from that covered the dark SEB ? What is meant by your statement that the ammonia was formed in place ? Did a pocket of nitrogen suddenly appear and mix with hydrogen ?
You've got nitrogen. You've got hydrogen. You've got a lot of possible catalytic molecules. You've got energy. I think it would be surprising if you didn't get ammonia.

I assume that what is seen in the cloud tops of gas giants is part of an ongoing synthesis engine. Certainly, the ammonia at the edge of the atmosphere must be undergoing dissociation in the sunlight.

Re: APOD: Dark Belt Reappearing on Jupiter (2010 Nov 29)

by dougettinger » Wed Dec 01, 2010 8:13 pm

You have me convinced. There are no high flying ammonia bodies. Where did the high flying light colored ammonia clouds come from that covered the dark SEB ? What is meant by your statement that the ammonia was formed in place ? Did a pocket of nitrogen suddenly appear and mix with hydrogen ?

Doug Ettinger
Pittsburgh,PA

Re: APOD: Dark Belt Reappearing on Jupiter (2010 Nov 29)

by Chris Peterson » Wed Dec 01, 2010 7:39 pm

dougettinger wrote:Yes, it is true that comet surveys should reveal approaching bodies near Jupiter. But some bodies like asteroids do not have comas or comets that have lost much of their surface volatiles, and may be missed in our incomplete asteroid surveys.
A coma is not necessary for detection. We are talking about a body many kilometers in diameter. Even with a very low albedo, such a body would probably be detected.
Neptune and Uranus have ammonia ices which were obviously produced in the outer solar system at some time and may reside in collisional debris.
Ammonia is easily produced by many chemical reactions in planets with atmospheres. Neither Neptune nor Uranus have ammonia ice in the sense "ice" is usually interpreted. Both planets probably have a lot of ammonia in their cores, in a phase state that might be called "ice", but which is hardly the same sort of thing you'd find in an icy asteroid or comet. This ammonia was certainly formed in place, not in the outer Solar System. There is absolutely no evidence at all that ammonia was produced in large quantities in the outer system, nor that ammonia bodies are present at all.

Re: APOD: Dark Belt Reappearing on Jupiter (2010 Nov 29)

by dougettinger » Wed Dec 01, 2010 7:22 pm

Yes, it is true that comet surveys should reveal approaching bodies near Jupiter. But some bodies like asteroids do not have comas or comets that have lost much of their surface volatiles, and may be missed in our incomplete asteroid surveys. Neptune and Uranus have ammonia ices which were obviously produced in the outer solar system at some time and may reside in collisional debris.

By "quick" I mean the disappearing and re-appearing SEB and the new appearance of the small Red Spot in the SEB.

Doug Ettinger
Pittsburgh, PA

Re: APOD: Dark Belt Reappearing on Jupiter (2010 Nov 29)

by Chris Peterson » Wed Dec 01, 2010 6:49 pm

dougettinger wrote:I am suggesting a frozen body comprised mostly of ammonia struck Jupiter in the SEB when the impact was hidden from our cameras. The impact aftermath may differ depending upon the materials in the body, the angle of impact, and its size. Also, the body could have broken-up or exploded into many pieces that became submerged in the SEB. The impact might not be immediately noticcable within the swirling cloud cover. Eventually, the ammonia material boils off and rises above the dark surface of the SEB. Gradually the lighter ammonia circulates around the latitude of impact and temporarily covers the dark band with its different reflective characteristics.
A lot of coulds, a lot of mights. It is hard to overlook the fact that no frozen ammonia body has ever been observed. Ammonia is a trace component in comets, present at less than a percent of the concentration of water. I don't even know of any reasonable mechanism that could produce ammonia bodies. And given the size of cloud-top effects we have seen from small impacts such as that of SL9, it is very difficult to believe that something capable of depositing enough material into Jupiter's atmosphere to completely disrupt a major equatorial belt would produce an invisible impact, or that it would even go unseen in comet surveys, since we are talking about an object tens of kilometers or more in diameter.
Quickly changing weather on Earth is due to the tilt of the spin axis, longitudinal currents in the oceans, and possibly solar winds.
I disagree with that assessment. These may be factors in our weather system, but they are hardly the only (or even dominant) factors contributing to the rapidity of change.
These factors do not exist for Jupiter. Quickly changing weather characteristics of darkening bands and spots on Jupiter may have other factors such as small to large random impacts of bodies of different compositions.
What is "quick"? Weather patterns on Jupiter- especially large scale ones- tend to be stable for very long times- months to centuries.

Re: APOD: Dark Belt Reappearing on Jupiter (2010 Nov 29)

by dougettinger » Wed Dec 01, 2010 6:29 pm

I am suggesting a frozen body comprised mostly of ammonia struck Jupiter in the SEB when the impact was hidden from our cameras. The impact aftermath may differ depending upon the materials in the body, the angle of impact, and its size. Also, the body could have broken-up or exploded into many pieces that became submerged in the SEB. The impact might not be immediately noticcable within the swirling cloud cover. Eventually, the ammonia material boils off and rises above the dark surface of the SEB. Gradually the lighter ammonia circulates around the latitude of impact and temporarily covers the dark band with its different reflective characteristics. The ammonia overtime disperses and the dark SEB re-appears. Jupiter's rings and irregular satellites definitely indicate its continued effectiveness to attract and capture asteroids and other rogues from interplanetary space.

Quickly changing weather on Earth is due to the tilt of the spin axis, longitudinal currents in the oceans, and possibly solar winds. These factors do not exist for Jupiter. Quickly changing weather characteristics of darkening bands and spots on Jupiter may have other factors such as small to large random impacts of bodies of different compositions.

I respect NASA's interpretations of their observations, but I try to keep an open mind.

Doug Ettinger
Pittsburth, PA

Re: APOD: Dark Belt Reappearing on Jupiter (2010 Nov 29)

by Chris Peterson » Wed Dec 01, 2010 4:46 pm

dougettinger wrote:I understand that the glare of the Sun from certain camera views would hide collisions. But also the camera view from a space probe can only see one hemisphere at any one time, and, hence, collision strikes can be hidden. Is this simple logic correct?
Sure. There are no probes currently in orbit around Jupiter, so all our recent images have been obtained from Earth (New Horizons flew by in 2007). Jupiter rotates once every ten hours, so it could take as long as five hours for a farside collision location to rotate into view. Two impacts have been observed which were large enough to alter cloud patterns, and those patterns persisted for weeks or months. Smaller impacts have been observed directly, but which produced no visible changes in the cloud patterns.

It is virtually certain that farside impacts have been missed. It is unlikely that any large impacts (> 1km) have been missed in recent years, however, as we'd expect evidence of them to persist much longer than the farside is blocked.

Re: APOD: Dark Belt Reappearing on Jupiter (2010 Nov 29)

by dougettinger » Wed Dec 01, 2010 4:10 pm

Chris Peterson wrote:
dougettinger wrote:No one has mentioned or suspected possible celestial collisions. Suppose a collision of a dominated ammonia body struck the SEB in early 2010 and dispersed ammonia hiding the SEB...
It seems unlikely. We have seen directly the results of collisions with relatively small bodies. They produce very obvious localized disruption of the cloud system, but no widespread effects. I think a collision large enough to disrupt an entire equatorial belt system would have been very obvious. For the last few years Jupiter has been under almost continual observation. Of course, there's a narrow window when it is too close to the Sun to observe, but I'd think there would still be visible effects of a collision once it re-emerged from the light of the Sun.

I'd describe the phenomenon as cyclic, but with no regular period. That is typical of many chaotic systems, and there is little that chaos theory is better at describing than weather patterns, whether on Earth or on Jupiter.
I understand that the glare of the Sun from certain camera views would hide collisions. But also the camera view from a space probe can only see one hemisphere at any one time, and, hence, collision strikes can be hidden. Is this simple logic correct ?

Doug Ettinger
Pittsburgh, PA

Re: APOD: Dark Belt Reappearing on Jupiter (2010 Nov 29)

by Chris Peterson » Wed Dec 01, 2010 3:51 pm

dougettinger wrote:What do you suppose caused the three semi-circles located in the middle of the SEB shown in the APOD ?
I don't know that anybody could say what "caused" them. They look to me like the start of vortex motion similar to that seen all along other bands, in storm systems, and often seen in cloud and wind patterns on Earth, as well. That sort of motion is common in dynamic fluidic systems.

Re: APOD: Dark Belt Reappearing on Jupiter (2010 Nov 29)

by dougettinger » Wed Dec 01, 2010 3:28 pm

What do you suppose caused the three semi-circles located in the middle of the SEB shown in the APOD ?

Doug Ettinger
Pittsburgh, PA

Re: APOD: Dark Belt Reappearing on Jupiter (2010 Nov 29)

by Chris Peterson » Wed Dec 01, 2010 1:50 am

dougettinger wrote:No one has mentioned or suspected possible celestial collisions. Suppose a collision of a dominated ammonia body struck the SEB in early 2010 and dispersed ammonia hiding the SEB...
It seems unlikely. We have seen directly the results of collisions with relatively small bodies. They produce very obvious localized disruption of the cloud system, but no widespread effects. I think a collision large enough to disrupt an entire equatorial belt system would have been very obvious. For the last few years Jupiter has been under almost continual observation. Of course, there's a narrow window when it is too close to the Sun to observe, but I'd think there would still be visible effects of a collision once it re-emerged from the light of the Sun.

I'd describe the phenomenon as cyclic, but with no regular period. That is typical of many chaotic systems, and there is little that chaos theory is better at describing than weather patterns, whether on Earth or on Jupiter.

Re: APOD: Dark Belt Reappearing on Jupiter (2010 Nov 29)

by dougettinger » Tue Nov 30, 2010 8:51 pm

Chris Peterson wrote:
RADDAD wrote:I observed this phenomenon about 20 or so years ago. I have it on a video and a still photo. It was before internet and I was between S&T subscriptions so all I could do was wonder what the heck was going on. I had been observing around 20 years at that time and had never seen it before. Now it is being talked of as unique. What should be discussed is how often does this occur.
I haven't seen any discussion of the disappearing belt phenomenon as "unique". Quite the contrary; it is regularly observed that this has been seen before. The only thing different this time is that a wealth of instrumented data is now available to study Jupiter, which has never before been the case.
The "cloud opera" explanation of this subject APOD more likely refers to the visual aspect of the opera. More important to me is the randomness of the changes. Changes sometimes occur in the north and sometimes in the south and are seldom interconnected. The cloud belt changes do not appear to have any cyclic properties. This recent APOD shows semi-circlar indentations spaced almost equally apart in the middle of the cloud band after the ammonia clouds dissapated revealing the dark band once again.

No one has mentioned or suspected possible celestial collisions. Suppose a collision of a dominated ammonia body struck the SEB in early 2010 and dispersed ammonia hiding the SEB. As it struck the molecular surface it broke-up into three major pieces forming the semi-circlar indents in a deeper frozen surface. The collision was not observed because it happened on the opposite side from our space probe camera positions. The SEB re-appears after the ammonia is dispersed or mixes with the present surface materials. Perhaps Jupiter is dutifully performing its job of sweeping up space trash. And the changing cloud belts and spots on Jupiter reveal these noble deeds.

Douglas Ettinger
Pittsbrugh, PA

Re: APOD: Dark Belt Reappearing on Jupiter (2010 Nov 29)

by bystander » Tue Nov 30, 2010 7:03 pm

DavidLeodis wrote:I learnt a new word from this APOD. :) With the image brought up through the "seen to change" link it states "Click to enzeusenate". I guess enzeusenate means enlarge, as a larger version of the image was then brought up. Strangely I did not find a defintion of enzeusenate when I did a simple search! :!:
Actually, you learnt it on Bad Astronomy. Phil Plait regularly coins new words to describe enlarging images. They all seem appropriate and humorous.

Re: APOD: Dark Belt Reappearing on Jupiter (2010 Nov 29)

by DavidLeodis » Tue Nov 30, 2010 2:54 pm

neufer wrote:
DavidLeodis wrote:
I learnt a new word from this APOD. :) With the image brought up through the "seen to change" link it states "Click to enzeusenate". I guess enzeusenate means enlarge, as a larger version of the image was then brought up. Strangely I did not find a defintion of enzeusenate when I did a simple search! :!:
en (L. in) zeus (Jupiter) enate (fr. L. enatus growing outward)

or...

enjeu (F. what is at stake) senate [fr. L. senatus, fr. senex, an old man]
Thanks neufer. I wonder if there is 'enjovianenate' as a synonym :?: :)

Re: APOD: Dark Belt Reappearing on Jupiter (2010 Nov 29)

by neufer » Tue Nov 30, 2010 2:03 pm

DavidLeodis wrote:
I learnt a new word from this APOD. :) With the image brought up through the "seen to change" link it states "Click to enzeusenate". I guess enzeusenate means enlarge, as a larger version of the image was then brought up. Strangely I did not find a defintion of enzeusenate when I did a simple search! :!:
en (L. in) zeus (Jupiter) enate (fr. L. enatus growing outward)

or...

enjeu (F. what is at stake) senate [fr. L. senatus, fr. senex, an old man]

Re: APOD: Dark Belt Reappearing on Jupiter (2010 Nov 29)

by DavidLeodis » Tue Nov 30, 2010 1:00 pm

I learnt a new word from this APOD. :) With the image brought up through the "seen to change" link it states "Click to enzeusenate". I guess enzeusenate means enlarge, as a larger version of the image was then brought up. Strangely I did not find a defintion of enzeusenate when I did a simple search! :!:

Re: APOD: Dark Belt Reappearing on Jupiter (2010 Nov 29)

by owlice » Mon Nov 29, 2010 11:04 pm

RADDAD and montylc2001, if you can digitize the images, it's be cool to have them on the Observation Deck for comparison with the recent disappearance of the belt. Instructions on how to post images are here: http://asterisk.apod.com/vie ... 29&t=22034

And if you need help or prefer that I post the images for you, please let me know. Thanks!

Owl

Re: APOD: Dark Belt Reappearing on Jupiter (2010 Nov 29)

by montylc2001 » Mon Nov 29, 2010 10:48 pm

RADDAD wrote:I observed this phenomenon about 20 or so years ago. I have it on a video and a still photo. It was before internet and I was between S&T subscriptions so all I could do was wonder what the heck was going on. I had been observing around 20 years at that time and had never seen it before. Now it is being talked of as unique. What should be discussed is how often does this occur.
I also observed this phenomenon in 1988 and have photos.

Re: APOD: Dark Belt Reappearing on Jupiter (2010 Nov 29)

by emc » Mon Nov 29, 2010 9:40 pm

indication is that the belt darkness is re-emerging from the clouds…
Image

Re: APOD: Dark Belt Reappearing on Jupiter (2010 Nov 29)

by mexhunter » Mon Nov 29, 2010 6:17 pm

10 years resolutions that we see today were a theory.
A very beautiful picture.
Greetings
César

Re: APOD: Dark Belt Reappearing on Jupiter (2010 Nov 29)

by Chris Peterson » Mon Nov 29, 2010 4:54 pm

RADDAD wrote:Thanks, Chris. The 'changes' link in the APOD notes takes you to a "sky is falling" site and that is what caused my comment.
Ah. I rarely follow YouTube links.

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