This is a drawing which illustrates the composition of Neptune's atmosphere relative to other possibilities for planets.
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A Look at what Neptune's Atmosphere is Made of

The atmosphere of Neptune is very similar to that of Uranus, and unlike that of Saturn and Jupiter. On Jupiter and Saturn, the atmosphere is mostly composed of the simple molecules hydrogen and helium. The atmosphere of Neptune contains more of the complex molecules such as methane gas, ethane gas, acetylene, and diacetylene. These constituents collectively are known as "hydrocarbons".

Hydrocarbons form hazes of smog high in the upper atmosphere. There are clouds of methane ice low in the atmosphere.

Neptune's atmosphere originally formed from complex molecules and ice, rather than the simple molecules of which Jupiter and Saturn formed.


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Neptune's Smog Hazes

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A Look at the History of Neptune's Atmosphere

The giant planets have definitely changed since their formation. But how much remains to be seen. Most of the original air of the giant planets remains in place. (The earth-like planets lost most of their...more

The Environment of Neptune

The air of Neptune is extremely cold, with temperatures of -270 degrees to -380 degrees. The air is made of complex molecules, the same sort of molecules that we see coming out of cars on earth in the...more

A Look at Neptune's Clouds

Like Jupiter and all the giant planets, Neptune's appearance shows a striped pattern of clouds. Other cloud shapes seen over time include a small dark spot, the "scooter" and the Great Dark Spot. The Great...more

An Overview of Neptune's Atmosphere

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Neptune's Present Great Dark Spot

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Neptune's Cirrus Clouds

This image shows some clouds known as "cirrus" clouds, extending for many kilometers across the face of Neptune. These clouds are very high up, for they can be seen to cast shadows on the lower clouds,...more

How the Solar System may have formed from a spinning cloud

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