Pluto's 'planet' debate reignited by New Horizons flyby

Story highlights

  • The New Horizon flyby of Pluto has inspired many to ask why the dwarf planet was demoted in the first place
  • Despite being larger than what scientists initially thought, size is not the only factor in classifying a planet
  • Social media users are hoping NASA will reconsider Pluto's planetary status

(CNN)Pluto hasn't gotten this much attention since the International Astronomical Union (IAU) reclassified it as a dwarf planet in 2006.

But NASA's New Horizons spacecraft flyby has rejuvenated Pluto's public image, and researchers are learning new things about the dwarf planet -- such as the fact that it is actually larger than previously thought.
Fresh measurements from New Horizons found Pluto to be 1,473 miles in diameter, which is about the vertical length of the United States.
The new information and images coming from the New Horizons have prompted some on social media to question whether Pluto's planetary downgrade should be reconsidered.
With so many passionate pleas to reinstate Pluto's former planet status, it begs the question: Why was Pluto downgraded in the first place?
Reddish-brown Pluto was reclassified as a dwarf planet by IAU, the organization that gets to name planetary bodies, based on the group's criteria (PDF) of what it takes to become a planet.
To be named as such, the celestial body must orbit the sun, be spherical or nearly round and must have cleared the area around its orbit.
Poor Pluto, the astronomical union said, wasn't big enough to knock other space rocks out of its path as it orbits the sun.
The decision to demote Pluto didn't go over so well with the general public though, which still harbors a fond attachment to the tiny celestial body.
The Harvard-Smithsonian Center for Astrophysics let people vote on whether they thought Pluto was a planet in 2014, and hands down, most people considered it to be one. Now there's a Change.org petition to declare Pluto a planet once again.
Even planetary scientist Alan Stern, the principal investigator for the New Horizons spacecraft, didn't agree with IAU's decision and claimed Pluto was booted out of its planetary status simply because of its distance from the sun.
"In fact, if you put Earth where Pluto is, it would be excluded!" Stern told CNN in January. "Any definition of planethood that excludes Earth, in any circumstance, is deeply flawed. After all, if there is any object everyone agrees is a planet, it's Earth."
Astrophysicist Neil deGrasse Tyson has been known to support the IAU reclassification of Pluto as a dwarf planet.
But with all the love Pluto has been getting, Tyson set the record straight with Internet users, sharing a cheeky photo with a caption saying they're friends, once again.
Jim Green, Director of Planetary Science Division at NASA Headquarter, said there's more to Pluto than its planetary status.
"[This mission] probably has reignited the debate," he said. "But from a NASA perspective we don't get involved in that. We really are not concerned about the nomenclature. What we're concerned about is going to the objects that are most important for us to understand the origin and evolution of the solar system."
According to NASA, Pluto's planetary status came into question after similar-sized celestial bodies were discovered deeper in the Kuiper Belt, the next destination for the New Horizons spacecraft.
There's no word yet from the IAU on whether Pluto will regain its status, but this week's excitement over Pluto's flyby from scientists, space enthusiasts and the general public alike, demonstrates that tiny Pluto, dwarf planet or otherwise, is much beloved here on Earth.