The idea of a ninth planet in the solar system is not new. In fact, Pluto was once considered the ninth planet, until it was demoted to a dwarf planet in 2006 by the International Astronomical Union (IAU), due to the discovery of other similar-sized objects in the Kuiper Belt, a region of icy bodies beyond Neptune.
However, Pluto’s demotion did not end the search for a true ninth planet, one that would be much larger and more massive than Pluto, and would have a significant gravitational influence on the solar system.
One of the main clues that suggest the existence of a ninth planet comes from the observation of a group of extreme trans-Neptunian objects (ETNOs), which are bodies that orbit the Sun at distances averaging more than 250 times that of the Earth.
These ETNOs have some peculiar orbital features, such as being clustered in one sector of the sky, and having similar inclinations and eccentricities. These alignments imply that there is an unseen planet that is shepherding these objects into their current orbits .
In 2016, two astronomers from Caltech, Konstantin Batygin and Michael E. Brown, proposed a theoretical model for this hypothetical planet, based on mathematical simulations and computer calculations.
They estimated that the planet would have a mass about 10 times that of Earth, and an orbit that is highly elongated and tilted with respect to the plane of the solar system.
The planet would take between 10,000 and 20,000 years to complete one revolution around the Sun, and would have an average distance of about 460 AU (astronomical units) from the Sun.
They
nicknamed this planet Planet Nine, and suggested that it could be the
core of a giant planet that was ejected from its original orbit by
Jupiter during the early formation of the solar system....<<<Read More>>>...