Friday, January 22, 2016

Solve for X


NASA Director of Planetary Science Jim Green comments on reports of a possible “Planet X” beyond the Kuiper Belt. Video source: NASA.

Two researchers at the California Institute of Technology announced this week the possible existence of a planet affecting objects in the Kuiper Belt.

(For the record, none of the researchers were named Cooper, Hofstetter, Koothrappali or Wolowitz.)

The article by Konstantin Batygin and Michael E. Brown was published January 20 by The Astronomical Journal. To read the paper, click here to download the PDF.

Mike Brown may be familiar to you, because his research into trans-Neputian objects (TNOs) was instrumental in the decision by the International Astronomical Union in 2006 to reclassify Pluto and other similar objects as “dwarf planets.” In 2010, Brown published a book titled, “How I Killed Pluto and Why It Had It Coming.”


A January 20, 2016 interview with Michael Brown by National Public Radio. Audio source: NPR.org.

The existence of the Kuiper Belt has been confirmed only since the 1990s. NASA's web site defines the Kuiper Belt as “ a disc-shaped region beyond Neptune that extends from about 30 to 55 astronomical units (compared to Earth which is one astronomical unit, or AU, from the sun). This distant region is probably populated with hundreds of thousands of icy bodies larger than 100 km (62 miles) across and an estimated trillion or more comets.” Although theorized for decades, its existence was proven in 1992 with the discovery of an object farther from the Sun than Pluto. The Belt was named after astronomer Gerald Kuiper, who in 1951 proposed that a belt of icy bodies might lay beyond Neptune.

Mike Brown in 2003 discovered Eris, an object about one-fourth larger than Pluto. Its discovery led to the debate within the astronomical world about the correct definition of a planet. The “dwarf planet” category was created by the IAU in 2006 to include Pluto and Eris. The list now includes Ceres, Haumea and Makemake. Ceres is in the asteroid belt near Jupiter, while the others are in the Kuiper Belt.


Eris in relation to the Kuiper Belt and Pluto. Click to view at a larger size. Image source: NASA.gov.

The discovery of more objects in the Kuiper Belt provided scientists with the opportunity to monitor their trajectories and how they might be affected by gravity from other objects, called an orbital perturbation.

The paper's abstract states:

Recent analyses have shown that distant orbits within the scattered disk population of the Kuiper Belt exhibit an unexpected clustering in their respective arguments of perihelion. While several hypotheses have been put forward to explain this alignment, to date, a theoretical model that can successfully account for the observations remains elusive. In this work we show that the orbits of distant Kuiper Belt objects (KBOs) cluster not only in argument of perihelion, but also in physical space. We demonstrate that the perihelion positions and orbital planes of the objects are tightly confined and that such a clustering has only a probability of 0.007% to be due to chance, thus requiring a dynamical origin. We find that the observed orbital alignment can be maintained by a distant eccentric planet with mass ≳ 10m⊕ whose orbit lies in approximately the same plane as those of the distant KBOs, but whose perihelion is 180° away from the perihelia of the minor bodies. In addition to accounting for the observed orbital alignment, the existence of such a planet naturally explains the presence of high-perihelion Sedna-like objects, as well as the known collection of high semimajor axis objects with inclinations between 60° and 150° whose origin was previously unclear. Continued analysis of both distant and highly inclined outer solar system objects provides the opportunity for testing our hypothesis as well as further constraining the orbital elements and mass of the distant planet.


Mathematical models suggest that an unknown force is acting on objects in the Kuiper Belt. Click the image to see at a larger size. Image source: California Institute of Technology.

The Cal Tech researchers refer to the theoretical world as Planet Nine, but others including NASA Director of Planetary Science Jim Green have nicknamed it “Planet X.”

Science magazine writes in its article about other claims to have found a Planet X in past decades. Conspiracy theorists claimed a dark planet named Nibiru is on a collision course with Earth, and NASA is part of a massive coverup.

Of course, any fan of Merrie Melodies has known since 1953 how to find Planet X.


How to find Planet X. Video source: Justin Edelson YouTube channel.

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