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Atmosphere of Jupiter

Each layer has characteristic temperature gradients.[4] The lowest layer, the troposphere, has a complicated system of clouds and hazes, comprising layers of ammonia, ammonium hydrosulfide and water.[5] The upper ammonia clouds visible at Jupiter's surface are organized in a dozen zonal bands parallel to the equator and are bounded by powerful zonal atmospheric flows (winds) known as jets.

The bands alternate in color: the dark bands are called belts, while light ones are called zones. The difference in the appearance between zones and belts is caused by differences in the opacity of the clouds. Ammonia concentration is higher in zones, which leads to the appearance of denser clouds of ammonia ice at higher altitudes, which in turn leads to their lighter color.[16]

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Wikipedia artist's ammonia planet (via Reddit)

The ammonia oceans, if it were just ammonia, would probably appear blue just like water. However unlike water ammonia can dissolve alkaline earth metals as if they were salt. When this happens the color changes. Dilute amounts of metal give it an intense blue color, slightly higher concentrations give it a gold bronze color as shown here. The reddish orange color in the atmosphere is due to oxides of nitrogen (nitrogen analogs for oxygen). Like Earth the atmosphere is primarily diatomic nitrogen. Unlike Earth it contains next to no free oxygen, but has nitrogen oxidizers. Most probably nitrous oxide, but it could be nitric oxide. It's hard for me to figure out which would be more likely. The planet would be much colder than Earth, so I depicted the vegetation as black to collect more light. Unlike water worlds like Earth, plants on ammonia worlds may not need to deprotonate water (or ammonia) molecules to get an electron for photosynthesis. This is because the dissolved alkaline earth metals release solvated electrons that can be used directly. This could free up photosynthetic plants to use a wider range of the spectrum. Finally ammonia clouds and ice are white just like those of water.

Commentary

Interestingly enough, not only does a solution like this have a metallic colour, but it’s also a good conductor of electricity. Even better than saltwater, in fact.

It’s hard to say which gas would be more likely, to be honest. Mind you, nitrous oxide (laughing gas) is actually colourless, and so is nitric oxide (decidedly less humourous gas).

Ammonia would need a lower average planetary surface temperature to be liquid. Lower temperature means less insolation from the planet’s host star, so plant analogs would need to have darker pigments to be more efficient. Which makes perfect sense. This would be a dark world to live on. That said, with less visible light, anything which evolved to live here would probably see in infrared.

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OSHA: Ammonia refrigeration

Anhydrous ammonia is a clear liquid that boils at a temperature of -28°F. Highly soluble with water Ammonia in water solution is called aqua ammonia or ammonium hydroxide. Because liquid ammonia boils at -28°F, the expanding gas has the potential to freeze anything in its path of release, including human flesh and organs. (Very chill)

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Hypothetical types of biochemistry – Ammonia

The ammonia molecule (NH3), like the water molecule, is abundant in the universe, being a compound of hydrogen (the simplest and most common element) with another very common element, nitrogen.[42]

However, ammonia has some problems as a basis for life. The hydrogen bonds between ammonia molecules are weaker than those in water, causing ammonia's heat of vaporization to be half that of water, its surface tension to be a third, and reducing its ability to concentrate non-polar molecules through a hydrophobic effect. Gerald Feinberg and Robert Shapiro have questioned whether ammonia could hold prebiotic molecules together well enough to allow the emergence of a self-reproducing system.[45] Ammonia is also flammable in oxygen and could not exist sustainably in an environment suitable for aerobic metabolism.[46]

A biosphere based on ammonia would likely exist at temperatures or air pressures that are extremely unusual in relation to life on Earth. Life on Earth usually exists within the melting point and boiling point of water at normal pressure, between 0 °C (273 K) and 100 °C (373 K); at normal pressure ammonia's melting and boiling points are between −78 °C (195 K) and −33 °C (240 K). Chemical reactions generally proceed more slowly at a lower temperature. Therefore, ammonia-based life, if it exists, might metabolize more slowly and evolve more slowly than life on Earth.[46] On the other hand, lower temperatures could also enable living systems to use chemical species that would be too unstable at Earth temperatures to be useful.[42]

Ammonia and ammonia–water mixtures remain liquid at temperatures far below the freezing point of pure water, so such biochemistries might be well suited to planets and moons orbiting outside the water-based habitability zone

Many Earth plants and animals undergo major biochemical changes during their life cycles as a response to changing environmental conditions, for example, by having a spore or hibernation state that can be sustained for years or even millennia between more active life stages.[74] Thus, it would be biochemically possible to sustain life in environments that are only periodically consistent with life as we know it.