In an intriguing development, astronomers have presented evidence suggesting the existence of a previously unknown ninth planet beyond Neptune, a theoretical world dubbed ‘Planet Y.’
This newly proposed planet could be similar in size to Earth and may exist alongside another candidate, potentially leading to a planetary count of ten if both hypotheses are validated.
Despite claims of the potential for discovery within three years, proof of Planet Y’s existence remains elusive, and skepticism among experts persists.
The search for a ninth planet has a long history, dating back to the discovery of Neptune in 1846 and reaching a brief conclusion in the 1930s with the identification of Pluto.
However, Pluto’s classification was revised in 2006, sparking renewed interest in the hunt for a ninth solar system world.
This modern search reignited in 2016 when Caltech astronomers Mike Brown and Konstantin Batygin introduced the Planet Nine hypothesis, suggesting that the strange orbits of distant objects beyond Neptune could be influenced by a massive, unseen celestial body.
This hypothesized world, often referred to as Planet X, is believed to be hiding in the Kuiper Belt, a vast region filled with asteroids, comets, and dwarf planets like Pluto, yet it has defied detection thus far.
Recent research published on August 21 in the Monthly Notices of the Royal Astronomical Society highlights claims of a new candidate for Planet Nine, which researchers have termed Planet Y.
The team behind the study determined that Planet Y likely resides within the Kuiper Belt and could be significantly closer to Earth than the theorized Planet X.
They found evidence that the orbits of 50 Kuiper Belt objects (KBOs) exhibit a 15-degree tilt compared to other planets in the solar system — a phenomenon they attribute to the gravitational influence of an undiscovered planet.
Study lead author Amir Siraj, an astrophysicist at Princeton University, emphasized that their findings do not represent a direct discovery of Planet Y, but rather identify a compelling puzzle likely needing a planetary solution.
The researchers estimate that Planet Y could be a rocky planet with a mass between that of Mercury and Earth, which is notably smaller than the proposed gas giant mass of Planet X.
Furthermore, they suggest that if Planet Y exists, it lies between 100 and 200 times further from the sun than Earth.
This distance places it relatively close to the orbit of Neptune, which orbits at 30 times the Earth-sun distance, making Planet Y much more accessible observationally than Planet X, predicted to be at least 400 times farther.
If Planet Y exists, it is expected to have an orbital tilt of up to 10 degrees compared to the plane of the eight known planets, further complicating the challenges of detection.
Despite the excitement surrounding Planet Y, some astronomical experts have raised concerns about the findings, citing the limited sample size of KBOs analyzed in the study.
Samantha Lawler, an astronomer at the University of Regina, expressed skepticism, stating that the results were not definitive due to the small number of KBOs evaluated.
Patryk Sofia Lykawka, an astronomer specializing in KBOs at Kindai University in Japan, acknowledged the plausibility of Planet Y but emphasized the need for further observations to support its likelihood.
To ultimately validate the existence of Planet Y or Planet X, astronomers will need either a stroke of luck that leads to direct observation, or an accumulation of additional data by observing more KBOs that align with the identified orbital patterns.
Significant progress in this search may soon be bolstered by the newly operational Vera C. Rubin Observatory in Chile, equipped with the world’s largest digital camera, which has commenced extensive night sky scanning.
Experts anticipate that this powerful observatory will uncover thousands of new KBOs in the near future, potentially providing the data necessary to solidify these planetary theories.
“I think within the first two to three years [of the observatory’s mission], it’ll become definitive,” Siraj stated, hopeful that if Planet Y falls within the telescope’s field of view, it could be directly identified.
Alternatively, if researchers do not uncover the hypothesized planets within this period, both theories may be abandoned altogether.
Planet Y is not the only candidate proposed as a potential ninth planet; several other hypothetical celestial bodies have surfaced but have mostly been disproven.
In May, a faint infrared signal raised hopes of a ninth planet’s existence, but that speculation was discounted when it was determined any object responsible would have to orbit in a plane perpendicular to other planets — a highly unlikely scenario.
Additionally, the idea that multiple rogue planets from other star systems could be captured by the sun’s gravity has been considered, with Siraj estimating the possibility of up to five Earth-like, rocky planets existing in the outer solar system.
Alternative theories also abound regarding the gravitational anomalies attributed to Planet X, suggesting they could stem from a primordial black hole or some unexplored form of gravity.
Others speculate that the elusive planet might be less massive and potentially surrounded by numerous moons.
The recent discovery of several dwarf planet candidates within the Kuiper Belt, like 2017 OF201 and 2023 KQ14, raises further doubts about the existence of Planet X, as these objects do not behave according to predictions made by the theory.
Ultimately, the search for our solar system’s elusive ninth planet persists, teaching us just how much we still have to learn about the cosmic secrets hidden at the outskirts of our neighborhood.
image source from：yahoo
