Okay, is Pluto a planet or not?
Back in 2006, the Solar System’s littlest planetary sibling lost its title. Now, 13 years later, people are still up in arms about Pluto’s loss of naming rights. Memes boast of its former glory and even popular TV shows like Rick and Morty feature running jokes about our family’s celestial dwarf. Although it’s accepted now that Pluto is a dwarf planet, many retain their loyalty to the little heart-wearing planet’s former title. Years of uproar could finally be paying off.
What’s in a name?
Before the turn of the millennium, planets outside of our solar system were nigh unheard-of. The concepts of life existing on other planets or water being found in significant quantities beyond Earth were absurd. As technology developed and our understanding of the universe around us grew, those ideas gradually began to shift. In 2006, astronomers held a conference in Prague where they set the definition for something their predecessors may have never imagined would be necessary: What is a planet? Back then, they defined a planet by three criteria. First, it had to be massive enough to maintain a round shape through its gravity. Second, it must clear a nearly-round orbital path of debris and other bodies. Finally, in our case, it must orbit the sun.
At the time of the summit where Pluto was demoted, the reason cited was that it didn’t fit the second point. Pluto’s orbit is far more elliptical than the other eight planets in our solar system. More importantly than that, it crosses paths with Neptune’s orbit. By the accepted definition of a planet, the overlapping orbits of the two worlds disqualified dear Pluto from holding the full title. Fortunately for Pluto supporters, however, there may be another renaming in the future for our little spherical friend.
In 2013, astronomers noted the existence of the discovery of a planet not bound to any star or system. Several others have been discovered, and one other has been confirmed. These rogue planets are roughly the size of Jupiter, and they drift through space all alone. But are they planets? They have no orbit to clear and no star around which to revolve. By definition, they wouldn’t be planets, yet NASA refers to them as such. What does that mean for Pluto?
The debate over Pluto’s nomenclature has finally led to some action. In April of 2019, astronomers gathered once again to discuss our ever-broadening understanding of the universe and all it holds. Their focus was to debate the current definition of a planet. The hullaballoo surrounding Pluto stems mainly from the inconsistency in its naming. Why shouldn’t it be a planet? It shows signs of tectonic movement and a possible subterranean ocean. It has five moons. It has an exosphere, which is a much thinner version of an atmosphere. It even has mountain ranges, and yet we classify it as a minor planet.
An informal vote revealed that the overwhelming majority of people present at the summit would rather see Pluto reinstated as a planet. Crowded though its neighborhood may be, Pluto maintains many characteristics typical of other rocky planets. Out where it lives in the Kuiper Belt, numerous rocky bodies orbit the sun at incredible distances. The conditions out there are reminiscent of the early solar system, where space was a hot commodity and larger planetoids comingled with smaller asteroids and bits of debris. Eventually, the rocky stragglers in the inner solar system organized into planets, moons, or shuffled into the asteroid belt. Out in the far-colder Kuiper Belt, the rearrangement never fully happened.
In future years, we could see Pluto gain back its old title. In the meantime, perhaps we ought not to judge a body quite so harshly for where it lives.