system
Given the following post, respond as if you're commenting on Reddit:
human
What elements/compounds give Jupiter its colors?

The atmosphere is mostly hydrogren and helium, with some trace elements. What gives color to those swirling bands?
gpt
**The short answer**: Hydrocarbon hazes, Rayleigh scattering, and some unknown compound.

**The long answer**: For the primary whites and browns that cover most of the planet, you need to realize that almost everything you see when you look at Jupiter is ammonia clouds, which on their own are bright white. Some latitudes are regions of upwelling (zones), and have high ammonia cloud-tops, while other latitudes are regions of downwelling (belts), and have low ammonia cloud-tops. In between these high and low heights sits a thick brown hydrocarbon haze, very chemically similar to smog. The cloud-tops in the zones are sticking up above most of the haze and thus appear fairly white. The cloud-tops in the belts, though, lie below the haze layer, and thus appear colored brown by the overlying haze.

For the occasional bluish regions seen just to the north and south of the equator, these are some of the rare cloud clearings that occur in very strong downwelling regions. We're actually peering through the ammonia top cloud layer, and perhaps even down through the ammonium hydrosulfide middle cloud layer and the bottom water cloud layer. So, in those regions we're looking at just clear air, which has the exact same color as it does one Earth, blue. This is entirely due to Rayleigh scattering, the same reason that Earth's sky is blue.

Then there's the reds, notably in Jupiter's Great Red Spot, although also occasionally seen in another big vortex here and there. As of right now, we don't actually know what makes the Great Red Spot red - this is generally known as the Jovian chromophore problem. Since this color is only seen in very large vortices, it's believed to be caused by some mixture of compounds already present on the planet getting pushed very high in the atmosphere by these vortices. In three dimensions, the Great Red Spot is essentially shaped like a wedding cake, so the cloud-tops at the center of the spot are at very high altitudes where there's a lot more ultraviolet light. You can end up producing all kinds of odd substances through UV photochemistry of trace substances in the atmosphere, and the working hypothesis at this point is that it's some kind of imine.