Dr. Stamatellos talks to CNA about the rise and possible fall of Planet “X”

CNA talked to Dr Stamatellos about the matter, on the occasion of a recent discovery that casts doubt on the hypothesis of the existence of Planet X
Planet “X” isn’t dead yet, but the evidence for its existence is growing weaker, Dr. Dimitris Stamatellos, Associate Professor at the University of Lancashire, UK, has told CNA, referring to the question of whether there is another planet in our solar system, the unknown planet ‘X’.
The five planets visible to the naked eye—Mercury, Venus, Mars, Jupiter, and Saturn—were known to the ancients. Two more, Uranus and Neptune, were added to the list about 200 years ago thanks to observations with telescopes.
But the of whether there are more planets in our Solar System remains unanswered.
CNA talked to Dr Stamatellos about the matter, on the occasion of a recent discovery that casts doubt on the hypothesis of the existence of Planet X.
He said that the further a planet is away from the Sun, the harder it becomes to detect, even with today’s most powerful telescopes.
“Planets at large distances from the Sun receive very little sunlight, making them faint and difficult to track,” he noted.
Pluto, he said, “was once considered the ninth planet, but it lost that status because it isn’t big enough to clear its orbit of debris — remnants of the material that formed the planets.”
“Such Solar System bodies are now classified as dwarf planets. A growing number of them have been found beyond the orbit of Neptune, earning them the name Trans-Neptunian Objects (TNOs),” he pointed out.
Interestingly, Stamatellos said, these Trans-Neptunian Objects appear to cluster in a certain region of the sky.
This unusual pattern, he explained, led some scientists to hypothesise the existence of an unknown super-Earth-sized planet, nicknamed Planet “X”, whose gravity might explain the clustering. This idea, proposed in 2016, reignited excitement in the planetary science community and drew widespread attention both in academia and the media, he said.
Since the proposal of this theory, Stamatellos told CNA, astronomers have searched for Planet “X”, but without success.
“It’s a difficult task: the sky area to be searched is vast, and any such planet would be extremely faint. Planet “X”, if it exists, might lie hundreds of times farther from the Sun than Earth. To complicate matters, its orbit could be inclined or elliptical, hiding it in parts of the sky that have not yet been fully explored. Observational searches have so far come up empty-handed,” he said.
Recently, however, he added, the discovery of a new Trans-Neptunian Object, called 2017 OF201, has cast doubt on the Planet “X” hypothesis.
He explained that this object lies roughly in the region where Planet “X” is predicted to reside.
“If such a big planet existed, it would destabilise 2017 OF201’s orbit, possibly ejecting it from the Solar System altogether. Its presence suggests that the observed clustering of Trans-Neptunian Objects might not require a big unknown planet after all,” he went on to say.
However, he continued, caution is still needed, adding that the orbit of 2017 OF201 is only roughly known, and further observations are required to confirm its properties. Also, he said, more Trans-Neptunian Objects need to be discovered in the same region in order for the current clustering to be explained.
Moreover, he said that orbital uncertainties are large for such distant objects because astronomers only see small portions of their orbits, which take thousands of years to complete and that more observations over time will help refine their orbits.
This finding doesn’t entirely disprove Planet X’s existence, he stressed.
“One possibility is that previous clustering may have been over-interpreted, a case of seeing patterns in a small dataset. Statistical biases in observations can sometimes produce apparent trends that disappear with more observational data. As we continue to discover more Trans-Neptunian Objects with new sky surveys, like the one to be conducted by the upcoming Vera C. Rubin Observatory, located in Chile, we’ll get a much clearer picture,” Stamatellos told CNA.
Referring to the Rubin Observatory’s Legacy Survey of Space and Time (LSST), he said it is expected to revolutionize our understanding of the distant Solar System by detecting thousands of new TNOs.
If a few more Trans-Neptunian Objects similar to 2017 OF201 are discovered, it would deal a huge blow to the Planet X theory, but if instead new objects are found that support the original clustering, the case for Planet X may rebound, he noted.
“Planet X isn’t dead yet, but the evidence for its existence is growing weaker. As in many areas of science, the answer may lie not in a single discovery, but in the slow accumulation of data and careful interpretation. Until then, the search continues,” Stamatellos said.
Concluding, he said that a few years ago, he predicted that if Planet X existed, it would have been discovered within a couple of years.
“The latest negative finding confirms my prediction. I don’t really want to fully close the door to a new planet, but perhaps the time has come to move on,” he told CNA.
Source: CNA