With Pluto's "demotion" to dwarf planet status, it’s understandable that the IAU faced criticism from the public for ...

In 2006, the International Astronomical Union (IAU) voted on the definition of a planet. Famously, Pluto no longer met the ...

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

“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 ...

Not fulfilling the second criteria, Pluto went from being the ninth planet in our solar system to one of five dwarf planets, with the IAU stating that Pluto is "an important proto-type of a new ...

“Pluto is dead,” announced California Institute of Technology astronomer Mike Brown then, during a teleconference of the vote by 424 astronomers following contentious debate during an IAU ...

Pluto is just 1,400 miles wide ... The vote happened on the last day of a two-week IAU meeting when only about 400 people were left, van Belle estimated. "There were many people, like me, who ...

According to the IAU, a planet must: Orbit the sun (Pluto does this). Be spherical in shape (Pluto is round due to its gravity). Clear its orbit of other debris (Pluto fails this). Pluto shares ...