A recently discovered celestial body is rewriting our knowledge of the Kuiper Belt and maybe challenging the existence of the ...

IAU members decided that there were three criteria to be a planet — and Pluto didn't meet all of them. But planetary scientist Wladymir Lyra says that even though it was downgraded to a dwarf ...

when the spunky world Pluto was demoted from a planet to a dwarf planet. Now, a team of astronomers is pushing for “planet” itself to be redefined to encompass bodies that orbit stars besides ...

When the International Astronomical Union (IAU) demoted Pluto from a planet to a dwarf planet in 2006, it surprised a lot of people, including some scientists. Even many years later, some ...

In August 2006 the International Astronomical Union General Assembly adopted a resolution to reclassify Pluto as a dwarf planet. The reasoning was that it didn't satisfy one of three newly defined ...

Ouch. Now officially labeled a “dwarf planet,” Pluto may have lost its title, but not our affection. After all, who doesn’t love a comeback story waiting to happen? To find out how Pluto ...

In this region, objects in space could cross any dwarf planet — and Pluto’s — orbit. Pluto also sits within a larger field of objects surrounding the solar system called the Kuiper Belt.

Arizona in 1930 and was considered our ninth planet until 2006. The International Astronomical Union reclassified Pluto as a dwarf planet because it does not clear its orbit of other debris.

Still, Ceres remains a dwarf planet. Perhaps as it should, given Pluto's relegation to dwarf planet — Pluto is 14 times larger than Ceres. Both Ceres and Pluto are given this designation because ...

Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute When the International Astronomical Union (IAU) demoted Pluto from a planet to a dwarf planet in 2006 ...