Planet 9 Existence: Evidence Points To Solar System’s ‘Missing’ Super-Earth

There is increasing evidence that a massive planet — dubbed Planet Nine, or Planet X — far beyond Neptune exists and is perturbing the orbits of an enormous number of objects stretching throughout the Solar System’s Kuiper Belt. Although the massive super-Earth-sized world has yet to be discovered, one proponent of its existence maintains that it is now difficult to imagine that it doesn’t exist. reported this week that Konstantin Batygin, a planetary astrophysicist at Caltech in Pasadena, California, and one whose team of scientists are actively searching for Planet Nine, contends that there is now five separate lines of evidence suggesting the existence of Planet Nine — a planet some 10 times the size of the Earth (a super-Earth) lurking somewhere far out in the outer Solar System.

“There are now five different lines of observational evidence pointing to the existence of Planet Nine,” says Batygin. “If you were to remove this explanation and imagine Planet Nine does not exist, then you generate more problems than you solve. All of a sudden, you have five different puzzles, and you must come up with five different theories to explain them.”

The original hypothesis that Planet Nine existed came from a 2016 paper from Batygin and his research partner, Caltech astronomer Mike Brown. The two contended that there were at least six objects (called extreme trans-Neptunian objects, or ETNOs) whose orbits were perturbed. Not only that, they all moved 30 degrees downward from the solar ecliptic, the relatively flat planetary plane where most objects orbit the Sun.

A third piece of evidence were computer simulations that suggested there should be more objects whose orbits were perturbed in a like manner. Discoveries of such objects soon followed.

Adding to the original hypothesis was work done by Elizabeth Bailey, who found that the existence of Planet Nine could be answer as to why the plane of the Solar System seems to be tilted some six degrees off from the Sun’s equator.

The fifth line of evidence shows up in objects in the Kuiper Belt that move opposite of everything else in the Solar System. The existence of Planet Nine would explain such “contrarians.”

horizontal view of Planet nine and others
Planet Nine is hypothesized to exist, possibly a product of our Sun's capture of a rogue planet or part of the Solar System's original planetary accretion disk. [Image by Vadim Sadovski/Shutterstock]

Along with the five lines of evidence is the astronomical survey data indicating the detection of extrasolar planets throughout our galaxy. This data shows a preponderance of evidence suggesting that most planetary systems exist wherein orbit super-Earths and worlds slightly larger. This data suggests that our own Solar System is anomalous and Planet Nine, which would be the right super-Earth size, would make our planetary system less unique and more in keeping with the observed consistencies of other systems.

The idea of a “missing” super-Earth notwithstanding, Batygin and company are not alone in thinking Planet Nine exists. As the Inquisitr reported in July, two Spanish astronomers published findings that supported Batygin and Brown’s original 2016 hypothesis that a colossal planet orbited some 20 astronomical units out from the Sun. The work of researchers from Complutense University of Madrid tracked over 50 objects, revealing indications that their orbits were being perturbed by a massive object further out in the Solar System.

Still, as Batygin himself notes, the final bit of evidence will be the actual discovery of Planet Nine itself…

[Featured Image by Vadim Sadovski/Shutterstock]