Pluto, the solar system object that everyone loves to fight the most.
Credit: NASA / Johns Hopkins University Applied Physics Laboratory / Southwest Research Institute
Scientists talked about classifying Pluto for 12 years, and a recently published article offers a new – but surprisingly old – reason to restore the planetary status of the object.
The new research focuses not only on the qualities of celestial bodies, but on the past 200 years of scientific literature. Four scientists trawled through astronomy documents published since 1802 in search of examples of the word planet used as defined by the controversial 2006 judgment of the International Astronomical Union (IAU) that again classifies Pluto as a dwarf planet. That group is responsible for handling the astronomical nomenclature. The definition included the requirement that planets "clear" their jobs, making them the gravitational large shots in their neighborhoods.
"We now have a list of more than 100 recent examples of planetary scientists using the word planet in a way that violates the IAU definition, but they do it because it is functionally useful," says lead author Philip Metzger, a planetary scientist the University of Central Florida, said in a statement released by the university. [Welcome Back, Pluto? Planethood Debate Reignites]
The new research focuses on how scientists have discussed asteroids in the past two centuries. This term was used interchangeably with "small planets" or even "planets" until the beginning of the 1950s, the researchers discovered.
The authors argued that the definition of the IAU, on which the group voted at its annual conference in 2006, attempts to replace the long historical use in the community. "We recommend that, in relation to planetary taxonomy, central agencies such as the IAU do not resort to votes to create the illusion of scientific consensus," wrote the authors. "The IAU has caused damage to the public perception of science, a process free of a centrally dictated authority, the imposition of a definition of planet and the number of planets that fit in that definition, which has been introduced in educational handbooks on the whole world based on their authority. "
(The authors have not commented on the fact that many certainly non-planets have been designated as planets in the history of scientific discourse, up to and including the sun.)
The definition agreed at this IAU meeting requires an object to meet three conditions to qualify as a planet: it must revolve around the sun, it must be massive enough that gravity is more or less in a spherical shape pulls, and it has to be around his job. Metzger and his co-authors argued that the third part of that definition does not correspond to the historical use by scientists and should be withdrawn.
I have fixed that headline about Pluto that you may have seen.
"I know you were not convinced by our first 78 arguments, but what about this?", Said one of the Exact Same Dudes. pic.twitter.com/z4yHTG9CTr
– Mike Brown (@plutokiller) September 7, 2018
None of the two scientists who dominated the demotion of 2006 are particularly impressed by the new article. Planetary scientist Mike Brown of Caltech, who so profoundly embraced his role in the debate that his Twitter handle is @ plutokiller, argued that those who want Pluto to be considered a planet simply search for whatever reason they can get. (He also referred to the fact that his Pluto nomenclature nemesis, Alan Stern, principal investigator of the New Horizons mission, was co-author of the new paper.) [Pluto Flyby Anniversary: The Most Amazing Photos from NASA’s New Horizons]
Brown's planetary researcher, Konstantin Batygin, also of Caltech, echoed many other scientists in calling for an end to bickering over terminology in favor of focusing on the quantitative characteristics of objects such as mass and orbit. "These quantities are important, not what we call them," he wrote on Twitter.
Re-classifying Pluto as a planet is akin to naming an island as a continent, a bit silly. But let us not forget that astrophysical bodies are characterized by mass, radius, orbit, etc. These quantities are not important, what we call them. https://t.co/oU69A7v9QP
– Konstantin Batygin (@kbatygin) September 7, 2018
Metzger did not agree with this, arguing that terminology is important, especially for the most prestigious group of objects in our solar system. "The IAU definition would say that the fundamental object of planetary science, the planet, is supposed to be defined on the basis of a concept that no one uses in their research," he said in the statement. "It would leave the second most complex and interesting planet in our solar system."
His later remarks made clear that he would classify the earth as the most complex planet in our solar system. But it is hard to believe that a scientist who is focused on one of our other neighbors can not be a perfectly compelling reason why, instead of Pluto, it is billing in second place – although Metzger Pluto as "more dynamic and vivid than Mars ". "
The research is described in an article published on August 29 in the journal Icarus.