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Neptune is the most distant planet known in the Solar System. The blue colour of the planet is due to its dense methane atmosphere. It is so far from the sun, that each of Neptune's seasons lasts for over 40 Earth years.

From time to time, Neptune develops relatively short-lived storm systems, which appear as dark-regions. Here the Great Dark Spot of 1989 can be seen, with the Small Dark Spot below it.

Image credit: Voyager 2, NASA.

Neptune Facts

Diameter: 49,528 kilometres (49 thousand, 528 kilometres), or 30,774 miles (30 thousand, 774 miles)

Distance from the Sun: 4,504,450,000 kilometres (4 billion, 504 million, 450 thousand kilometres), or 2,798,900,000 miles (2 billion, 798 million, 900 thousand miles)

Rotation period (day): 16.1 hours

Orbital period (year): 164.79 years or 60,182 Earth days or 89,666 Neptunian days

Cloud-top temperature: -218 degrees Celsius, or -360 degrees Fahrenheit

Moons: 14 in total, namely, Naiad, Thalassa, Despina, Galatea, Larissa, S/2004 N 1, Proteus, Triton, Nereid, Halimede, Sao, Laomedeia, Psamathe and Neso

High wispy clouds cast shadows on the lower cloud deck.

Image credit: Voyager 2, NASA

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