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

[dougettinger]

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

[Chris Peterson]

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.

[dougettinger]

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

[Chris Peterson]

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.

[dougettinger]

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

[Chris Peterson]

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.

[dougettinger]

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

[Chris Peterson]

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.

[dougettinger]

Chris, thank you for this excellent discussion. Doug

[RADDAD]

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!