Scientists Suggest Existence of Earth-Like Planet in Outer Solar System
The discovery of peculiar clustering behaviors among trans-Neptunian objects (TNOs) in the far reaches of the Solar System has led scientists to propose the existence of a hidden world, referred to as Planet Nine. However, two researchers have now put forth an alternative explanation, suggesting the presence of a more modest, Earth-like planet located closer to us than Planet Nine.
Planetary scientists Patryk Sofia Lykawka and Takashi Ito have proposed the idea of a frozen and dark planet, no bigger than three times the mass of Earth, located within 500 astronomical units from the Sun. They believe this hypothetical planet and several TNOs with peculiar orbits in the outer solar system could provide testable evidence for their proposed planet.
While Pluto is known to be at an average distance of about 40 astronomical units from the Sun and the most distant known single object in our Solar System was found at a distance of 132 astronomical units, the Kuiper Belt extends even further. Beyond Neptune lie numerous icy rocks and dwarf planets, known as TNOs, which exhibit clustering patterns that suggest the presence of a significantly larger gravitational influencer.
In 2016, astronomers Mike Brown and Konstantin Batygin proposed the existence of Planet Nine, which they estimated to be around 6.3 times the mass of Earth and orbiting at a distance greater than 460 astronomical units. However, Lykawka and Ito are not the first scientists to suggest an explanation for this phenomenon. In 2008, Lykawka and colleague Tadashi Mukai proposed a hypothetical hidden Kuiper belt planet to explain TNO clustering.
With new data on TNOs becoming available, Lykawka and Ito have revisited the idea and refined it, identifying the properties of their proposed planet. They suggest that an Earth-like planet with a mass between 1.5 and 3 times that of Earth, an orbit with a most distant point from the Sun between 250 and 500 astronomical units, and an inclination of 30 degrees relative to the plane of the Solar System, could explain several peculiarities observed in the Kuiper Belt.
Their findings could potentially explain objects with inclinations greater than 45 degrees, the elongated orbit of dwarf planet Sedna, as well as the properties of TNO groups linked to Neptune. The researchers believe that further observations and improved techniques and instruments could potentially confirm or rule out the existence of their hypothetical planet.
The existence of such a planet in the outer solar system could provide new insights into planet formation and the dynamical evolution of the trans-Jovian region. Lykawka and Ito’s research has been published in The Astronomical Journal, and their proposed planet offers testable signatures that could potentially shed light on the mysteries of our Solar System’s far reaches.