The day that will always live in infamy: August 26, 2006. It was not the day that an unfavorable politician took office, nor was it that of an international humanitarian crisis. It was the day that Pluto was downgraded from a planet to a dwarf planet, lowering the number of planets in the Solar System from nine to eight.
As BBC reported, the International Astronomical Union (IAU) met in August to discuss the criteria on what should constitute as a planet. What spurred this was the discovery of Kuiper Belt Objects (KBO) that had similar masses in comparison to Pluto.
A professor from the California Institute of Technology, Dr. Mike Brown, led a team of researchers that helped to discover one of these objects, Eris. Based on his and others findings, the members of the assembly voted on three points to label an object as a planet. The IAU describes that Pluto qualifies in the first two categories; being that it is a celestial body that orbits the sun and that it has a round shape.
The last point however, that it has essentially sent away other objects around its area or achieved “gravitational dominance” as the BBC reported, is something that Pluto does not fulfill. Since Dr. Brown’s discovery led to Pluto’s downgrading, he has enthusiastically called himself the “man who killed Pluto.”
Had the guideline been made with only the first two points, the results would have been drastic as Professor Iwan Williams, the IAU’s president of planetary systems science, remarked, “By the end of the decade, we would have had 100 planets, and I think people would have said ‘my goodness, what a mess they made back in 2006.’”
The new guidelines properly classified Pluto as a dwarf planet along with the rest of KBO in the area, like Eres or Sedna. This is a fact that many scientists and scientific organizations agree with.
Unfortunately, there have been scores of people arguing the opposite position, that Pluto is indeed a planet. “Viva La Pluto” is the title of a blog post written by Marie Terese Fox from Pennsylvania State University, arguing in vain that Pluto is a planet, as she had learned in her childhood.
Fox is probably one of many students who remember learning about Pluto in school, but new evidence challenges old perspectives. This is how science has word for millennia.
The debate rages on despite the fact that this decision was made years ago. An article from Space.com quoted Alan Stern, a planetary scientist who disagrees with the IAU saying, “if you take the IAU’s definition strictly, no object in the solar system is a planet.” Stern further remarked that, “no object in the solar system has entirely cleared its zone.”
If we take his line of logic, we would have to re-classify nearly all KBO discovered, meaning we would have hundreds of planets. This is not the right move to take, nor does it bear out the facts. Pluto does not have gravitational dominance and is much smaller than any other planet in our solar system, says Vox.
Unlike the rigidity of religion, science changes, not on the whims of opinions or feelings, but on facts and evidence that support new findings. The fact of the matter is that Pluto does not meet the scientifically agreed upon criteria of the IAU that determines what is a planet. As the astrophysicist Neil deGrasse Tyson told Good Reads, “The good thing about science is that it’s true whether or not you believe in it.”