Two Pluto moons discovered in June 2005 named Nix and Hydra by IAU

The International Astronomical Union (IAU) officially named two small Pluto moons, discovered in June 2005, Nix (the inner of the two) and Hydra (the outer of the two) [1-3]. The discovery was made by the Pluto Companion Search Team, led by Hal Weaver and Alan Stern, using the high-resolution capabilities of the Hubble Space Telescope. Nix and Hydra are roughly 5,000 times fainter than dwarf planet Pluto itself.

Pluto was discovered in 1930. The first discovery of a Pluto moon, Charon, happened in 1978. The two Pluto satellites spotted in 2005 were originally designated S/2005 P 2 and S/2005 P 1 and then named Nyx and Hydra, respectively, by the discovery team [1,2]. But the Greek name Nyx had already been taken as an identifier for asteroid 3908 and the IAU changed Nyx to its Egyptian equivalent, Nix [1].

Pluto was named after the god of the underworld. Mythologically, Nix and Hydra fit right in there: Nix is the goddess of darkness and night [4]. Hydra is a terrifying monster with the body of a serpent and nine heads [5].  

Keywords: astronomy, planetary science, solar system, celestial bodies, discovery, nomenclature, mythology

References and more to explore
[1] Michael Buckley and Maria Martinez: Pluto's Two Small Moons Christened Nix and Hydra [www.jhuapl.edu/newscenter/pressreleases/2006/060622.asp].
[2] Richard A. Lovett: Pluto's New Moons Named Nix, Hydra [news.nationalgeographic.com/news/2006/06/060623-pluto.html].
[3] Neil deGrasse Tyson: The Pluto Files. W. W. Norton & Company, New York and London, 2009; pages 44 and 45.
[4] Greek goddess Nyx was the personification of the Night: www.greek-gods.info/ancient-greek-gods/nyx/.
[5] Ron Leadbetter in Encyclopedia Mythica: Hydra [www.pantheon.org/articles/h/hydra.html].