Pluto’s fourth and fifth moons named

Two tiny, recently-discovered satellites of dwarf planet Pluto have new named ratified by the International Astronomical Union; P4 is renamed Kerberos and P5 is renamed Styx. The names – related to the “underworld” theme that has governed the naming of Pluto and its moons to date – overlooks a popular online vote that suggested one of the moons should be named Vulcan, after Mr. Spock’s home planet in Star Trek. Kerberos, discoverd in 2011, is believed to be approximately 20 miles in diameter and orbits Pluto at a distance of roughly 37,000 miles. Styx, first sighted in 2012, is even smaller, with an estimated diameter of 15 miles, orbiting only 1,200 miles from Pluto, making it the innermost satellite (a distinction previously held by Pluto’s near-twin, Charon). NASA’s New Horizons spacecraft will have the opportunity to see the new moons up close when it does a flyby of Pluto in 2015.