Astronomers claim discovery of ‘Planet X’ in outer solar system, others not so sure

By Ryan Whitwam 

Identifying objects in the outer reaches of the solar system is a surprisingly difficult endeavor. Pluto wasn’t discovered until the early 20th century, and other Kuiper Belt objects weren’t spotted until the last decade or so. This uncertainty has led some to speculate about the possibility of another planet out there — a so called Planet X. Now a team of astronomers thinks they might have found it. The scientific community is understandably skeptical. Let’s break it down.

The term “Planet X” has been used to refer to all manner of hypothetical and completely imaginary objects over the years (look up the Nibiru conspiracy theory if you want a laugh). Pluto was even considered a Planet X of sorts after its discovery. The term has mostly been applied to an object thought to be causing gravitational disturbances in the orbits of Neptune and Uranus. However, studies in the late 1970s lowered the calculated mass of Neptune and eliminated the discrepancy. An undiscovered massive object in the outer solar system has not been seriously considered since then… well, until now.

The researchers used the Atacama large millimeter/submillimeter array (ALMA) in Chile to detect two objects somewhere at or beyond the orbit of Neptune. The research has been published openly on the arXiv archive, meaning it has not yet been peer-reviewed for official publication. The authors point out they are hoping the astronomical community will take a look at the findings and present alternative explanations for the findings. Should the work be found lacking, the papers will be withdrawn.

There are only two observations for each object, and the details are sketchy at best. According to one of the two papers, a large rocky object the size of Ireland is in orbit somewhere near Neptune. They call this object “Gna.” However, the paper goes on to explain that Gna could also be a larger planet somewhat farther out, or even a brown dwarf (a failed star) passing through nearby interstellar space. The other object is unnamed and is alleged to be a super-Earth that orbits at the extreme edge of the solar system near the transition to alpha centauri. This one too could apparently be a brown dwarf passing through interstellar space.

With just two blips for each of these objects, most astronomers are dismissing the research as an unjustifiable leap of faith. The papers have been submitted to the prestigious Astronomy & Astrophysics Journal for review. It sounds like the team will most likely be sent back to the drawing board to accumulate more evidence of the supposed Planet X candidates.