A long time ago, we all grew up in the calm reassurance that our solar system had nine planets. Pluto, was beloved by many as the smallest planet that was out at the farthest reaches of our solar system. But, not being happy with the status quo, the International Astronomical Union got together to debate whether or not Pluto had the right to be a planet at all. The results of the meeting demoted the little planet and the outcry around the world even surprised the IAU.
In the meeting held by the IAU they made some decisions on what rules and guidelines should be used to define a planet:
1} The object has to be in orbit around our sun
2} The object has to have sufficient mass to assume a nearly round shape (hydrostatic equilibrium)
3} The object have a ‘cleared neighborhood’ around its orbit.
Unfortunately, Pluto does not have a ‘cleared neighborhood’ and it was demoted. The members of the IAU that supported the demotion included the astronomer Mike Brown, who was a major reason lowly Pluto was removed from the school books. Famed astrophysicist Neil Degrasse Tyson was also a proponent and, since he was more of a celebrity, was seen and heard on a higher level that Brown, explaining the reasons for the removal of ‘planet status’. No matter how many members there were in the decision, Tyson seems to have received the blame for it all, receiving hundreds of letters from children explaining why they wanted Pluto back.
However, once Pluto was demoted, it didn’t stop the cries and objections, and the popularity of the little object (which is smaller than our moon) prompted a meeting on September 18, 2014 at the Harvard-Smithsonian Center for Astrophysics. At this meeting, they made the decision to take a vote from the audience on the planetary status of Pluto, and, it was voted back in.
Alan Stern, the principal investigator for the New Horizons spacecraft (the first one sent to Pluto) is one of the few people that has spoken out against the original demotion decision. He used the argument that the original demotion was based on Pluto’s distance from the sun and stated,
“In fact, if you put Earth where Pluto is, it would be excluded!” Stern said. “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.” Stern seems to be quite pleased that the decision has been overturned.
Tyson seems to agree with the decision to change Pluto’s status to a ‘dwarf planet’ but Stern, on the other hand, remains adamant that Pluto should be reinstated with full ‘planetary rights’. There is a current rumor that the two are talking about setting up a debate that will be televised; if this is so, it will be a space geek’s ‘must-see’ event and would promise to carry quite a bit of weight as we observe the two powerhouse voices fight-it-out.