New Evidence Suggests Presence of a Ninth Planet

Pluto may not have made the cut, but astronomers believe they have now enough evidence to theorize a new ninth planet.

Back in 2006, world citizens mourned the loss of Pluto’s planet status, as Neptune’s next-door-neighbor was kicked to the curb. Mike Brown, an astronomer at Caltech, played a big role in demoting Pluto. He says he has no regrets; in 2010 he wrote a book titled How I Killed Pluto and Why It Had It Coming, where he explains the logic behind the Pluto controversy.

Which was probably a good thing; losing Pluto was a big deal. We had grown up believing there were nine planets, and now one of them was thrown off the menu without so much as a going away party. Brown was bombarded with reporters, and children were writing hate mail. Now he thinks he may have been wrong, and that there might be a ninth planet that we never before knew existed.

On Wednesday, January 20, the California Institute of Technology announced that there was enough evidence the theorize a giant icy planet even further out than Pluto, and much, much bigger. In fact, the supposed new planet is estimated to be two to four times the diameter of earth, with a rotation if 10,0000 to 20,000 Earth Years.

Brown and his colleague, Konstantin Batygin, published their findings in an essay on the Astronomical Journal, entitled “Evidence for a Distant Giant Planet in the Solar System.”

From The New Yorker:

They have not observed it [the new planet] directly, only inferred its presence from the behavior of a handful of faraway objects, which have been caught in its gravitational sway. After more than a year of watching, calculating, and conducting computer simulations, Brown and Batygin write, “We motivate the existence of a distant, eccentric perturber.”

Currently the planet, which Brown and Batygin have nicknamed Planet Nine, Jehoshaphat, George, and Fatty, is still just a theory. It’s sort of a mysterious icy giant that’s floating just far enough in the distance to be considered part of the solar system, but too far to be seen. Essentially, this big guy likes his privacy.

Still, the evidence is promising. From The Albany Daily Star:

Brown and Batygin’s theory is based on how the new planet and its gravitational field would be the explanation behind why dwarf planets and smaller objects in our solar system orbit differently compared to the eight planets. The astronomers believe that the massive ice planet was flung into deep space by the gravitational force of Jupiter or Saturn.

This is a key factor in providing evidence for Planet Nine. Planets, by definition, have enough mass and gravity to affect other objects within our solar system. While researching the Kuiper Belt, a population of icy objects orbiting the sun, Brown and Batygin found a specific and eccentric object they named Sedna. Its orbit was well outside the Kuiper Belt, which suggested that there is a larger force organizing the object’s rotation. After a year and half of followup research, the two came to the conclusion that there might be a giant planet controlling the orbit of these other random objects. Essentially, another planet would explain this wacky rotation.

So if “George” exists, he fits the textbook definition of “planet.” Brown explains that planets are currently defined as being “objects that can gravitationally dominate their neighborhood.” This explains why Pluto no longer makes the cut; it’s a slave to the gravitational influence of Neptune. Planet Nine takes up more of the solar system than any other known planet. Brown believes that you can argue this bad boy is more of a planet than anything else currently in the solar system.

But for now, the details remain iffy. Brown and Batygin hypothesize that the planet is made predominantly of ice and rock, with an atmosphere of 10 to 20 percent hydrogen and helium, which is a similar makeup to that of Uranus and Neptune. As for location, the two estimate can use the information they have regarding Planet Nine’s orbit to make some basic estimates. Brown says that his best guess is that Planet Nine is in the November sky. They plan on gathering more specific information in the next two to eight years.

Luckily, the response to this discovery has been far more favorable than when Pluto got the boot. From

“Mostly, the reaction has been very positive, especially from our colleagues that have read the paper. They’re more or less compelled by the arguments,” Batygin says. “There’s been also a bit of skepticism, which we are very happy with. … Ultimately what we are hoping here is that this theoretical prediction of the orbit will trigger a hunt, an observational hunt for Planet Nine. That’s the goal of this paper.”

A hunt, indeed. For the past few decades, other astronomers have speculated over the existence of a “Planet X.” Now they’ve been gifted with some fresh information. And since nothing is set in stone, it means we’ll  have to keep exploring.


Amanda Kohr is a 25-year-old writer and photographer with a penchant for yoga, food, and travel.  She prefers to bathe in the moonlight rather than the sun, and enjoys living in a state of the three C’s: cozy, creative, and curious. When she’s not writing, you can find her driving her VW Bug, looking for the next roadside attraction or family diner. She also roams the internet at and through Instagram.