X Marks the Spot

The following article contains information from a variety of sources. The works referenced are listed at the end.

In 2006, many people’s hearts were broken when Pluto was essentially declared too insignificant to be considered a planet, and instead was assigned the slightly less honorable title of dwarf planet.  

Konstantin Batygin and Mike Brown from the California Institute of Technology argue that the main reason behind this decision was that newly discovered bodies in the Kuiper belt that were larger than Pluto were not considered to be planets.  The discoveries of those objects prompted astronomers at the 26th General Assembly of the International Astronomical Union to clearly define the true meaning of a planet.  After some deliberation, the scientists created three criteria that needed to be fulfilled for a planet to be officially a planet and ultimately, our beloved Pluto did not meet all the requirements.

In January, there was a possibility of avenging Pluto’s demise when Batygin and Brown announced that they had reasonable suspicion that a ninth planet existed.  (Funnily enough, Brown played a major role in demoting Pluto’s status and also authored a book titled How I Killed Pluto and Why It Had It Coming.)

The main argument behind the existence of the planet, dubbed Planet X, is how nearby bodies are influenced by its supposed existence.  Batygin and Brown observed that some gravitational force caused some Kuiper Belt Objects (KBOs) to have strange orbits.

planetx-520px
The red oval is Planet X’s orbit as predicted by Batygin and Brown. The smaller green ovals are the small extreme Kuiper objects that helped Sheppard determine the existence of Planet X. Image by Scott Sheppard.

 Scott Sheppard, whose research influenced much of Batygin and Brown’s, further elaborates on this, proposing that a massive object, something he dubs the “great disturber,” could greatly alter the paths of other objects that come near it.  Objects coming near it tend to a more stable state, which is at a position far away from the disturber.  As a result, any object that comes near the disturber will have their orbits altered to keep it as far from the disturber as possible.

Physics teacher Jim Birdsong compares the planet’s interaction with nearby KOBs with cars on a road full of leaves, saying that once enough cars drive across it, there is an empty space, similar to how disturbers clear out their own paths.  There are two important elements in this analogy: the empty space, representing how Planet X pushes KBOs out of its way as well as the number of cars, which represents the mass of the planet.  In order to have a significant effect, the mass of the planet must be relatively large.  Planet X’s mass has been estimated to be at least ten times the mass of the earth, so it will definitely have a clear effect, even if observed from earth.  As Birdsong put it, Planet X is big enough to create “a little region where only [it lives] … sort of like marking [its] territory.”

Six nearby bodies’ orbits are all tilted in the same manner, which, according to Brown’s simulations, is as likely to randomly occur without outside influence as “ having six hands on a clock all moving at different rates [and] … [looking] up [when] they’re all in exactly the same place”.   To be more specific, Planet X effects a component of orbit called the argument of perihelion, which is essentially the direction of a planet’s orbit relative to its position to the sun .  The matching of the argument of perihelion for nearby bodies can be well explained through the effects of Planet X’s gravitational pull.

One might wonder, if Pluto was rejected as a planet, what makes Planet X qualify as one?  As mentioned before, Pluto did not meet the IAU’s requirements, but it was very close.  In resolution B5, the IAU declared that a planet of our solar system orbits the sun, can use its own gravity to become spherical, and has “cleared the neighborhood around its orbit” (as described above).  While Pluto orbits the sun and is massive enough to assume a spherical shape, it is like the numerous asteroids and comets in space, too small to be able to create its own territory.  On the other hand, Planet X seems to meet all three requirements.  Like Pluto, it orbits the sun and is large enough to allow its own gravity to make it round.  As for the third requirement, the main scientific proof of Planet X’s existence demonstrates how it clears its neighborhood, so if Planet X exists, then it can be considered a planet.

And there is the main problem.  Planet X has not yet been seen.  While Batygin and Brown state that the probability of the observed effects of its existence happening by coincidence is considerably less than than 1%, many other astronomers have differing opinions and theories.  David Jewitt, a scientist who discovered the Kuiper Belt, commends the pair for their extensive research but voices some of his doubts, stating that the error margin should be lowered significantly before this research can be taken seriously.  Similarly, Hal Levison of the Southwest Research Institute recommends people to be wary and not immediately believe the results because “[he has seen many, many such claims in my career, and all of them have been wrong.”

Assuming Planet X exists, there are quite a lot of implications and effects.  For example, according to Freeman Dyson, it may be possible to use Planet X as a slingshot to aid space travel.  By picking up speed as it approaches the planet and firing the rockets when a it is closest to the planet, a spacecraft can accelerate faster and save fuel, which is a valuable resource in space.  However, this idea, even under ideal circumstances, would not provide that much of a benefit.  Instead, the biggest impact of the discovery of the planet  is that it forces scientists to redefine the boundaries and of our solar system as well expand their views.  

Birdsong points out that “if you have a theory of how a solar system develops then sticking a planet way out in your backyard and seeing if it still follows the rules would be a good test of your theory.”  In other words, if your if this planet does exist, and the scientific community is forced to think of new ideas, it is more of a benefit then a drawback, for making a more universal set of laws would be better for our overall understanding of the solar system.  

Other than contributing to the scientific community, the discovery of this planet seems to be of no use to ordinary people.  After all, the planet is 30 billion kilometers away and is not even proven to be habitable.

Birdsong agrees with this sentiment saying that “it would be of benefit to other scientists, not so much so much to to Joe Plumber on the street … or help the stock prices.”  This is especially true considering the amount of time that is required in order to confirm Planet X’s existence and gather data and once the data is analyzed, there is no direct effect on people’s daily lives.  

However, junior Brandon Lee has a slightly different viewpoint.  Lee believes that in general, discoveries such as Planet X’s help encourage more people to support NASA and other space programs.  The constant progress being made in terms of astronomy may pique the interests of many young people with great potential.  

Overall, even though the discovery of Planet X is far from confirmed, it forces us to rethink the way we look at our own solar system, something we have learned about since elementary school.  As the philosopher Plato put it, “astronomy compels the soul to look upwards and leads us from this world to another.”  Perhaps we are like the people of the Middle Ages, who thought the earth was flat, and are simply looking at this problem the wrong way.  In any case, this discovery can only lead to even more revelations, further expanding our views about not only our own world, but ones beyond even the scope of our most powerful telescopes as well.


References

https://www.newscientist.com/article/2074961-how-planet-nine-may-have-been-exiled-to-solar-systems-edge/

http://www.theatlantic.com/science/archive/2016/01/planet-nine-may-help-us-slingshot-our-way-to-the-stars/425010/

http://www.graphpad.com/www/data-analysis-resource-center/blog/statistical-significance-defined-using-the-five-sigma-standard/

http://www.iau.org/static/resolutions/Resolution_GA26-5-6.pdf

https://www.caltech.edu/news/caltech-researchers-find-evidence-real-ninth-planet-49523

http://www.nature.com/news/evidence-grows-for-giant-planet-on-fringes-of-solar-system-1.19182

http://iopscience.iop.org/article/10.3847/0004-6256/151/2/22/meta#aj522495s2

http://www.scientificamerican.com/article/strong-evidence-suggests-a-super-earth-lies-beyond-pluto1/

http://www.sciencemag.org/news/2016/01/feature-astronomers-say-neptune-sized-planet-lurks-unseen-solar-system

http://www.techtimes.com/articles/82451/20150906/some-scientists-interested-in-searching-for-planet-x.htm

http://ssd.jpl.nasa.gov/?glossary&term=w