Clyde Tombaugh discovered Pluto in 1930 at Lowell Observatory in Flagstaff. Here's how Pluto won - and lost - its planetary ...

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 ...

Back in 2006 our Solar System lost a planet, not because it disappeared, but because it was reclassified. Pluto, now considered a dwarf planet, failed one of the three tests the International ...

Pluto fails the third criterion because its orbit overlaps with objects in the Kuiper Belt, a region of icy bodies beyond Neptune. So, a new class of celestial object — the dwarf planet — came ...

was once considered the ninth planet in our solar system. In 2006, the International Astronomical Union reclassified Pluto as a dwarf planet because it doesn't meet all the criteria for full ...

“New Horizons shattered a major paradigm of planetary science,” says Alan Stern, the mission’s principal investigator. “Pluto turns out to have as much complexity as Mars or Earth, so much so that I ...

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.