Nix

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Pluto and its large moon, Charon, appear overexposed in this Hubble Space Telescope image obtained in 2006 to confirm the existence of the two small moons Nix and Hydra (at right).

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Nix

moon of Pluto

Also known as: P2, S/2005 P2

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July 17, 2026

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Pluto and its large moon, Charon, appear overexposed in this Hubble Space Telescope image obtained in 2006 to confirm the existence of the two small moons Nix and Hydra (at right).

Nix is one of Pluto's five known moons. It was discovered in 2005 and is much smaller than Pluto's largest moon, Charon. Nix orbits Pluto in a nearly circular path and is in a stable dynamic resonance with Charon and the other smaller moons: Hydra, Kerberos, and Styx. The orbital periods of these four moons are in a 6:5:4:3 ratio, meaning they periodically pass one another.12

Nix is named after Nyx, the Greek mythological personification of night and a significant cosmological figure. While Nyx was already assigned to an asteroid, a variant spelling was used for the moon. Nix is an elongated moon with a diameter of approximately 88 kilometers. Unlike most moons in the solar system, Nix is not in synchronous rotation with Pluto, meaning its rotation period is not the same as its orbital period.321

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Christening Pluto’s Moons
Nix
Here is a little lesson in the value of variant names: in Greek mythology Nyx is the female personification of night and a great cosmological figure, awesome even to Zeus himself. According to the Greek poet Hesiod, she was the daughter of Chaos and…
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Here is a little lesson in the value of variant names: in Greek mythology Nyx is the female personification of night and a great cosmological figure, awesome even to Zeus himself. According to the Greek poet Hesiod, she was the daughter of Chaos and…
Read More

Pluto
Pluto’s moons
Pluto’s other four moons—Hydra, Nix, Kerberos, and Styx—are much smaller than Charon. All four are elongated. They revolve around Pluto outside Charon’s path in nearly circular orbits (like Charon) and in the same orbital plane as Charon. The orbital radius of Hydra is about 64,721 km (40,216 miles); that…
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Pluto’s other four moons—Hydra, Nix, Kerberos, and Styx—are much smaller than Charon. All four are elongated. They revolve around Pluto outside Charon’s path in nearly circular orbits (like Charon) and in the same orbital plane as Charon. The orbital radius of Hydra is about 64,721 km (40,216 miles); that…
Read More

Hubble Space Telescope
…used to discover Hydra and Nix, two moons of the dwarf planet Pluto.
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…used to discover Hydra and Nix, two moons of the dwarf planet Pluto.
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New Horizons
…four smaller moons of Pluto—Styx, Nix, Kerberos, and Hydra—were found to be spinning very rapidly, unlike most other satellites in the solar system, which keep one side facing the planet they orbit.
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…four smaller moons of Pluto—Styx, Nix, Kerberos, and Hydra—were found to be spinning very rapidly, unlike most other satellites in the solar system, which keep one side facing the planet they orbit.
Read More