US Scientists Say Solid Evidence For Ninth Planet In Solar System

The solar system appears to have a new ninth planet.

Two US-based scientists from California Institute of Technology (CalTech) recently announced that a giant, previously unknown planet might have been discovered lurking in the outer circle of our solar system.


The planet has been nicknamed ‘Planet Nine’ and “has a mass about 10 times that of Earth.”

They further added in a statement:

“It follows a bizarre, highly elongated orbit in the distant solar system. In fact, it would take this new planet between 10,000 and 20,000 years to make just one full orbit around the Sun.”

The two CalTech researchers are Konstantin Batygin and Mike Brown. They disclosed they have not yet observed the object directly but only found it through mathematical modelling and computer simulations.


Giving Planet Nine’s description, they said that it is 5,000 times the mass of Pluto and that its gravity affects the motion of dwarf planets in the outer solar system.

It also essentially perturbs celestial bodies in the field of icy objects and debris beyond Neptune and that is called the Kuiper Belt.

To better explain how this works, CalTech’s statement gives example of a child on a swing being pushed by a parent and added:

“Like a parent maintaining the arc of a child on a swing with periodic pushes, Planet Nine nudges the orbits of distant Kuiper Belt objects such that their configuration with relation to the planet is preserved.”

Mike Brown achieved popularity when he co-authored on a paper that ultimately become a leading force in the downgrade of Pluto from one of the planet to that of dwarf planet in 2006.


He at that time had found another dwarf planet called Eris, which was more massive than Pluto and thus had become a potential candidate for the 10th planet of the solar system.


But, things had turn the other way around when later in 2006, the International Astronomical Union instead of inducting Eris as the 10th planet issued a new definition of the word “planet,” according to which neither Eris nor Pluto made the cut.

Following this, Brown had assumed the name @plutokiller on Twitter and on January 20, posted:


When questioned how could so many astronomers miss Planet Nine for so long, Brown and Batygin explained that it could have become a cast off planet during the early formation of the solar system and as years progressed the major cores in that area grabbed up the gas around them and formed Jupiter, Saturn, Uranus and Neptune.


Although speculations about another planet in our solar system has been going on for decades, scientists from all across the world have been sceptical about it.

Batygin, who is an assistant professor of planetary science in CalTech, explained that they too were “initially quite sceptical that this planet could exist” but they continued to investigate Planet Nine’s orbit with the question of what it would mean for the outer solar system and over the years “become increasingly convinced that it is out there.”


On finding out about Planet Nine, Robert Massey, deputy executive director of Royal Astronomical Society, London said that it was for “the first time in over 150 years” that there was solid evidence that the solar system’s planetary census is incomplete.

The last time that a planet was discovered by mathematical modelling was back in 1846, when Neptune was found.


Massey though cautioned that not every prediction has led to an actual planet and that there had been instances in the past when planets were predicted, but never found.

On the positive note, he added that both the researchers on CalTech’s published paper are well respected and thus their hypothesis was definitely worth following up.

To read this study this research in more detail, please visit The Astronomical Journal.

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