This is a response I sent to the one-sided article "Searching for Planet 9" published April 19, 2022, in Big Think by writer Tom Hartsfield along with a request that I or another writer be given the chance to write a response presenting the other side of this ongoing debate.
As you are likely well aware, the debate over planet definition and over Pluto's status remains ongoing. Just four percent of the IAU voted on the controversial demotion of Pluto and related planet definition, and most were not planetary scientists but other types of astronomers. Their decision was immediately opposed by an equal number of planetary scientists in a formal petition led by New Horizons principal investigator Alan Stern.
Notably, the four percent of the IAU who voted on this misused the term "dwarf planet," which Stern coined back in 1991 to refer to a new subclass of planets by stating in their resolution that dwarf planets are not planets at all but another type of object entirely. Nine years later, this statement was not borne out by the findings of the Dawn mission at Ceres and the New Horizons mission at Pluto.
Since the 2015 New Horizons mission revealed Pluto to be a geologically active world with complex processes seen elsewhere in the solar system only on Earth and Mars, an increasing number of planetary scientists have come to view it as a full-fledged planet
At the Lunar and Planetary Sciences Conference in 2017, planetary scientist Kirby Runyon introduced the geophysical planet definition, which rejects the notion that an object has to clear its orbit to be a planet. Unlike the IAU definition, the geophysical definition focuses on objects' intrinsic properties rather than their location and deems any object that is not a star but is large enough and massive enough to be rounded by its own gravity a planet.
Because so many planetary scientists prefer the geophysical definition, they object to the term "Planet 9" for the hypothetical but as yet undiscovered planet in the outer solar system. Advocates of the geophysical definition count dwarf planets as full planets, so they view the solar system as already having a minimum of 13 planets and counting. In the August 5, 2018, edition of Planetary Exploration Newsletter, a publication of the Planetary Science Institute, a group of planetary scientists objected to the insensitive, one-sided use of the term "Planet 9," noting the IAU planet definition is "far from universally accepted."
At the Lunar and Planetary Sciences Conference in 2017, planetary scientist Kirby Runyon introduced the geophysical planet definition, which rejects the notion that an object has to clear its orbit to be a planet. Unlike the IAU definition, the geophysical definition focuses on objects' intrinsic properties rather than their location and deems any object that is not a star but is large enough and massive enough to be rounded by its own gravity a planet.
Because so many planetary scientists prefer the geophysical definition, they object to the term "Planet 9" for the hypothetical but as yet undiscovered planet in the outer solar system. Advocates of the geophysical definition count dwarf planets as full planets, so they view the solar system as already having a minimum of 13 planets and counting. In the August 5, 2018, edition of Planetary Exploration Newsletter, a publication of the Planetary Science Institute, a group of planetary scientists objected to the insensitive, one-sided use of the term "Planet 9," noting the IAU planet definition is "far from universally accepted."
Instead, they requested this hypothetical world be referred to by the standard term for a hypothetical but as yet undiscovered planet, which is "Planet X," with "X" referring to the unknown rather than to the number 10.
Hartsfield's article unfortunately begins with an extremely one-sided statement, "The former planet 9, Pluto, was knocked out of the club because it failed to meet the definition of a planet" without noting that that definition is just one of several currently in use and remains controversial to this day.
It then continues with the article's first sentences reading, "Our solar system once possessed nine planets. Then we kicked Pluto out of the club because it was just one of several little things beyond Neptune. Pluto happened to be the largest of them, putting it right on the line between planet and Kuiper Belt speck. The hunt is on for the real planet 9--if it exists."
This sentence contains multiple problems. There is no "we" that kicked Pluto out of the club. The sentence assumes a level of consent that never existed, especially among planetary scientists. It does not even acknowledge the fact that most planetary scientists reject the IAU definition and have done so for over 15 years.
Furthermore, Pluto is far from a "Kuiper Belt speck" or even an object between a planet and a speck. Such a statement totally ignores the New Horizons findings, which found Pluto to have planetary processes such as geology and weather, likely geological layering, floating glaciers, a layered atmosphere, interaction between its surface and atmosphere, varied terrains, windswept dunes, cryovolcanism, and a likely subsurface ocean. No Kuiper Belt "speck" has these features; such specks, like asteroids, are simply loosely held together by their chemical bonds.
This sentence contains multiple problems. There is no "we" that kicked Pluto out of the club. The sentence assumes a level of consent that never existed, especially among planetary scientists. It does not even acknowledge the fact that most planetary scientists reject the IAU definition and have done so for over 15 years.
Furthermore, Pluto is far from a "Kuiper Belt speck" or even an object between a planet and a speck. Such a statement totally ignores the New Horizons findings, which found Pluto to have planetary processes such as geology and weather, likely geological layering, floating glaciers, a layered atmosphere, interaction between its surface and atmosphere, varied terrains, windswept dunes, cryovolcanism, and a likely subsurface ocean. No Kuiper Belt "speck" has these features; such specks, like asteroids, are simply loosely held together by their chemical bonds.
Big Think's readers deserve a far more fair and balanced reporting of this issue, which acknowledges the ongoing debate and both positions instead of portraying one side as fact. There are many planetary scientists who would be happy to write about this for you, and I would be happy to get you in touch with them.
No comments:
Post a Comment