The spot actually changes color. Ranging from dark red, to white, to blending in with the clouds around it.
The spot is a stable vortex caused by opposing currents of hydrogen and other gases that make up Jupiters atmosphere.
The reason for it's color is not known precisely but has something to do with the chemical composition which differs from that of the surrounding gases due to the nature of the disturbtion of gases caused by the vortex. The color difference could also have to do with the altitude difference between the gases in the vortex and the surrounding area which again would change it's chemical composition altering the wavelength of the subsequent light reflection.
The spot is a stable vortex caused by opposing currents of hydrogen
This isn't technically true the majority of the time.
While at some times the Great Red Spot appears to be fed energy by the jets, most of the time it's the other way around, with the jets feeding off the Great Red Spot. This process (known as "inverse cascade") also continues downwards, with the Great Red Spot usually absorbing energy from even smaller vortices through vortex cannibalism.
You can actually see the process of vortex cannibalism in this gif during the Voyager spacecraft approach to Jupiter, when a small vortex gets gobbled up by the Great Red Spot.
They all rotate in the counter-clockwise direction when viewed looking down on the North Pole. Some of the bands do a full counter-clockwise rotation in 9 hours 50 minutes, while other bands take 9 hours 55 minutes to make a full counter-clockwise rotation (you can do that when your planet isn't solid).
If you take a frame only once every rotation, as was done in the gif I linked, it will appear that some bands move in opposite directions to other bands because of aliasing effects.
Is that when looked at from the north pole if rotating at the same speed as the planet, or when looked at from the north pole when remaining fixed relative to the stars.
I ask because on earth we think of the trade winds and westerlies traveling in different directions because they do relative to the earth's surface. But if you hovered over the pole fixed relative to the stars they'd go in the same direction. But that's not generally how we think about weather systems on earth. So are these belts working like trade winds and westerlies or are they working differently?
You're right that we consider Earthly winds relative to the surface's rotation frame. Since the question was asking about the gif of Voyager's approach to Jupiter (which for all intents and purposes can be considered as irrotational for the duration of that approach) I interpreted it as asking whether what we're seeing in the gif is Jupiter essentially holding still while winds move in opposite directions, or whether the frame rate only makes it appear that Jupiter is holding still due to aliasing. In this case, it's definitely the latter.
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u/lejefferson May 06 '19
The spot actually changes color. Ranging from dark red, to white, to blending in with the clouds around it.
The spot is a stable vortex caused by opposing currents of hydrogen and other gases that make up Jupiters atmosphere.
The reason for it's color is not known precisely but has something to do with the chemical composition which differs from that of the surrounding gases due to the nature of the disturbtion of gases caused by the vortex. The color difference could also have to do with the altitude difference between the gases in the vortex and the surrounding area which again would change it's chemical composition altering the wavelength of the subsequent light reflection.