Why was pluto reclassified as a dwarf planet?

Even though Pluto is a dwarf planet, and no longer officially a planet, it’ll still be a fascinating target for study. And that’s why NASA has sent their New Horizons spacecraft off to visit it. New Horizons will reach Pluto in July 2015, and capture the first close-up images of the (dwarf) planet’s surface. read more

In 2006, Pluto was reclassified as a dwarf planet, a change widely thought of as a demotion. The question of Pluto's planet status has attracted controversy and stirred debate in the scientific community, and among the general public, since then. read more

In August 2006 the International Astronomical Union (IAU) downgraded the status of Pluto to that of "dwarf planet." This means that from now on only the rocky worlds of the inner Solar System and the gas giants of the outer system will be designated as planets. read more