One of the most popular theories to explain the strange movement of objects in the outer solar system is the presence of the so-called Planet Nine that some astronomers think could be messing up with the orbits beyond Neptune.
Astronomers have observed that several trans-Neptunian objects (TNOs), were "detached" from the strong gravitational influence of the gas giants in the Solar System. They also have weird looping orbits.
Astronomers proposed that a large planet-like object could be causing these orbits.
Some TNOs were also observed to be clustered together in a way that did not appear random. Modeling suggested a giant but unseen planet could be tugging these objects into their position.
In 2016, Konstantin Batygin and Mike Brown named this object Planet Nine.
This hypothetical planet is believed to be ten times more massive than Earth and influences the movements of the TNOs through its gravity.
Planet Nine remains elusive, and while astronomers continue to search for this world, a team of researchers proposed an explanation that could mean Planet Nine need not exist to account for the strange movements in the outer reaches of the Solar System.
Astrophysicist Antranik Sefilian, from the University of Cambridge, and Jihad Touma, from the American University of Beirut, proposed that instead of a big object, the combined gravitational forces of smaller TNOs are behind the orbital wobbles.
Collective Force Of Small Objects
The researchers modeled the TNOs, planets of the Solar System, and a massive disk of debris beyond Neptune's orbit and were able to account factors such as the mass and orientation of the disk for the looping orbits of the detached TNOs.
"If you remove planet nine from the model and instead allow for lots of small objects scattered across a wide area, collective attractions between those objects could just as easily account for the eccentric orbits we see in some TNOs," Sefilian said.
The researchers are set to publish their study in the Astronomical Journal.