12 things to know about Pluto

Published 4:10 PM EDT, Thu July 9, 2015

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Is Pluto still a planet?

Is it at the end of our solar system?

(CNN) —  

NASA’s New Horizons probe flew past Pluto on July 14, 2015 becoming the first spacecraft to study Pluto up close. Here’s what you need to know about the icy world.

1. Is Pluto still a planet? Yes, but it’s now a different kind of planet. Many of us grew up thinking there were nine planets in our solar system: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune and Pluto. In 2006, the International Astronomical Union (IAU) touched off a huge debate when it reclassified Pluto as a dwarf planet.

Why the change? Astronomers started finding many more objects in our solar system that are about the same size as Pluto. Rather than call all of these objects planets, the IAU created a new category called dwarf planets. So far, five dwarf planets have been recognized by the IAU: Pluto, Ceres, Eris, Makemake and Haumea. Scientists expect to eventually confirm many, many more dwarf planets. Dwarf planet Ceres currently is being explored by NASA’s Dawn spacecraft.

2. Where is Pluto? It’s about 3.6 billion miles (5.8 billion kilometers) away from the sun in the Kuiper Belt, a disc-like region of space beyond Neptune where thousands of other small, icy objects orbit. The Kuiper Belt is named in honor of Dutch-American astronomer Gerard