Pluto may not be a planet anymore, but it does have a new companion: scientists have discovered the icy dwarf's smallest moon yet, bringing the count of its known moons to five.
"We're not finished searching yet," Hal Weaver, of Johns Hopkins University, told the Associated Press.
The new moon — known as S/2012 (134340) 1, or the less clunky P5 — was discovered by the Hubble space telescope, which was observing Pluto in anticipation of the arrival of NASA's New Horizons spacecraft in 2015, reported the AP. The planet's tiny new companion appeared as a faint fleck in the Hubble images.
According to Wired, the moon with an irregular shape measures between six and 16 miles across. It circles Pluto in a 30,000-mile-radius orbit, which is roughly an eighth of the distance at which our moon orbits Earth.
National Geographic reported that P5's diameter makes it about two-thirds the size of P4, another of Pluto's moons, which was discovered in 2011, and is some 3.7 billion miles from the sun.
P5 joins not only P4, but also Charon, Nix and Hydra in orbit around the dwarf, according to Fox News. Scientists believe that Pluto's very complex system, including its many moons, is the result of a collision between the dwarf planet and another large object billions of years ago.
"The discovery of so many small moons indirectly tells us that there must be lots of small particles lurking unseen in the Pluto system," Weaver told Fox News.
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