When the International Astronomical Union revised their official working definition of what constitutes a planet in 2006, many astronomers were less than pleased. The vague new definition of a planet was far from precise and left quite a bit of gray area for what could and could not be defined as a planet.
As a result, Pluto was stripped of its planetary status and instead demoted to a dwarf planet. Since then, the petite planet has perpetually perplexed planetary scientists, who have thrown all sorts of contradictory and unique classifications at Pluto.
Now, a team of NASA scientists has proposed a new set of rules for classifying planets, published in the journal Lunar and Planetary Science. According to the proposal, the new definition is intended to remedy some of the unintended consequences of the IAU’s new definition:
In the decade following the supposed “demotion” of Pluto by the International Astronomical Union (IAU), many members of the public, in our experience, assume that alleged “non-planets” cease to be interesting enough to warrant scientific exploration, though the IAU did not intend this consequence.
Burn! The IAU is gonna need some ointment after that one. The panel of NASA astronomers wrote this new definition of a planet based on what they call the “intuition” of the public rather than overly-technical and specific orbital properties the IAU used in their 2006 ruling. If this new proposal is accepted by the IAU, it would potentially add over 100 new planets to our Solar System:
With the above definition of a planet, we count at least 110 known planets in our Solar System. This number continues to grow as astronomers discover more planets in the Kuiper Belt. Certainly 110 planets is more than students should be expected to memorize, and indeed they ought not. Instead, students should learn only a few (9? 12? 25?) planets of interest.
While a common criticism of this new definition is that students would be unable to memorize all of the planets, the authors cite the example of the periodic table; school children are not expected to memorize all of the elements, but instead focus on a few select elements while learning how to read the Periodic Table as a whole.
The authors claim this new definition will “resonate happily” with the public. Is 110 planets too many? Does this really even matter, or is it just a case of an academic squabble over who gets to publish certain data?