Neptune
The windiest planet in our solar system
Neptune is the eighth and farthest-known Solar planet from the Sun. In the Solar System, it is the fourth-largest planet by diameter, the third-most-massive planet, and the densest giant planet. It is 17 times the mass of Earth.
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Neptune's internal structure resembles that of Uranus. Its atmosphere forms about 5% to 10% of its mass and extends perhaps 10% to 20% of the way towards the core. Neptune's core is likely composed of iron, nickel and silicates.
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Neptune's atmosphere is 80% hydrogen and 19% helium. A trace component of methane is also present. Because of its great distance from the Sun, Neptune's outer atmosphere is one of the coldest places in the Solar System.