ORLANDO, Fla. – For almost 80 years, children learning about the solar system were told we had nine planets. Pluto was one of them. It was small, cold and distant, but it was still a planet. Then a team of Caltech astronomers found Eris, it was also small, but almost the same size as Pluto and the International Astronomical Union took Pluto’s planet status away creating the new term “dwarf planet.”
Eris is named after the Greek goddess of strife and discord, which is what the debate over Pluto’s status created among the global astronomy community ever since the 2006 decision, known as the IAU Resolution. According to the IAU, Brown found that fitting.
The IAU explained its decision to declare that our solar system has eight planets plus, a new class of objects called dwarf planets, as “a testament to the fluid nature of science and how our view of the Universe continues to evolve with changes made by observations, measurements and theory.”
The wound gets opened frequently when researchers find new reasons to restore Pluto to its former glory as a planet. That’s exactly what happened last week when UCF’s Florida Space Institute planetary scientist Phil Metzger published his study in the journal Icarus taking on the IAU’s definition of a planet.
Metzger said the IAU definition leaves out "the second-most complex, interesting planet in our solar system.”
Thanks to NASA's 2015 flyby mission of Pluto with the New Horizon spacecraft we now know just how interesting the small world is. The public and science community were in awe at the images New Horizon captured, including methane ice dunes, mountain ranges and valleys. Pluto even has a heart-shaped surface feature, which could be part giant sinkhole. Pluto, it's just like us. Can't it just be the ninth planet again?
However, this isn't about if Pluto will be "replanetized." This is about why the tiny world matters to so many people, not only to the scientists who are arguing for either side, but the general public. I posed the question to a group of space enthusiasts on Facebook and received different answers. Their responses are included with permission.
For some, what Pluto is classified has made no difference.
"The exact term used to describe and categorize Pluto should be based on reason and observation, not on sentimentality or tradition. It remains exactly the same object, no more or less interesting than it was before," Joe Bergeron wrote.
Teacher Christine Nobble adapted her lesson plans to also teach students about Pluto and other small bodies.
"It is a planet, a dwarf planet. Or a minor planet. Or a trans-Neptunian object. Or a Kuiper Belt Object. Pluto fits into many 'categories.' The ongoing discussion about the number of planets in the Solar System (aren't we at 23 now?) does keep people interested!" wrote Nobble. "I am still teaching 13 because I can't find an image of the 23! Mercury, Venus, Earth, Mars, Ceres, Jupiter, Saturn, Uranus, Neptune, Pluto, Humea, Makemake, Eris."
"I don't care at all. Does it matter if we call Ceres 'the smallest planet' or 'the greatest of the minor planets of the inner solar system?'" wrote Christopher Carson.
Pluto has always fascinated the public and the interest with the New Horizons mission was proof of that.
"I think what’s most important is WHAT motivates a society to choose to invest in exploring Pluto (or any other space object)," Jim Zeitler said. "Pluto continues to have 'name recognition' since it was dethroned as a planet just 12 years ago. So planet or not, we are still sending space probes there."
It also matters to some because Clyde Thombaugh, who found Pluto, is no longer living to defend his discovery.
"Mr. Thombaugh passed away in 1997 allowing many generations of folks to meet him. While I’ve met some notable people I did not meet him, though I know other lucky amateur astronomers who did," Steven Smith wrote. "Most of those I know who met him feel as if his accomplishment has been stripped off his arm and any future mention of him would be small blurbs of unimpressionable comments."
Former NASA Jet Propulsion Laboratory employee Jackie Alan Giuliano said people will always root for Pluto as the underdog.
"The last project I worked on was called Pluto Express, a precursor to New Horizons. By then I had switched from engineering to education and I ran the Educational Outreach program. Pluto was 'deplanetized' around that time."
"We had kids and adults from all over the world telling us that Pluto deserved to be a planet. Thousands of them. There's something about Pluto that brings out the underdog in most of us. We at JPL all felt the same: 'Pluto is a planet!'"
Others agreed: Pluto will forever be a planet.
"Pluto is a planet, albeit small. It is every bit a planet the same way a dwarf hippopotamus is still a hippo," said Robert Ray Little.
"My head knows Pluto is a dwarf planet. My heart will always see Pluto as the Ninth Planet," said Martin Lollar, adding that as a child he grew up fascinated by the discovery of Pluto in the Space Age.
While the astronomy community continues to debate Pluto's status in our solar system, to some, it will always be important no matter what's called.
If you have a reason why it matters if Pluto is a dwarf or among the primary planets tweet me @emspeck or email me at firstname.lastname@example.org.