A Ninth Planet Exists!

Past Kuiper Belt

We know something big lurks out in the far ends of this solar system. It appears to be a new ninth planet. Two scientists, Mike Brown, and Konstantin Batygin, announced evidence of a body possibly the size of Neptune orbiting the sun every 10,000-20,000 years. When our solar system was born 4.5 billion years ago, they say, this giant planet was kicked from the planet-forming region near the sun.

Its closest approach to the sun is seven times farther than Neptune’s distance, or 200 Astronomical Units, or AUs. An AU is the distance between Earth and the sun, or ~210 million miles. Planet X could roam as far as 600 to 1200 AU, which is well beyond the Kuiper belt. This region has only small icy worlds beginning where Neptune has its orbit at 30 AU.

A Good Hypothesis

If Planet X exists, Brown and Batygin say astronomers should find more objects in understandable orbits, all affected by gravity of the unforeseen planet. But Brown understands Planet X won’t exist until it appears in a viewfinder. Before there’s a direct detection, it’s only a very good hypothesis.

Batygin and Brown specifically concluded its presence from the clustering of six previously known objects orbiting beyond Neptune. Since there’s only a 0.007% chance the orbiting asteroids’ paths could be a coincidence, they believe a planet has brought those six large asteroids into elliptical orbits, out of the Solar System’s plane. The researchers found six of the 13 Kuiper belt objects moved on orbits that headed in the same direction. Looking down on the solar system with the sun in the center, all of these objects would orbit to the 9 o’clock position. Moreover, their orbits were all tilted at the same angle to the eight known planets in the solar system.

Batygin and Brown published this result recently in The Astronomical Journal. Brown discovered Eris, and showed this planet was just one of the Kuiper belt. Astronomers reclassified Pluto as a dwarf planet-which Brown recounted in his book “How I Killed Pluto.”

planet nine orbit.
The suggested orbit of Planet Nine. (Data) JPL; Batygin and brown/CalTech; (Diagram) a. Cuadra/Science http://www.sciencemag.org/sites/default/files/styles/inline_colwidth__4_3/public/images/Orbits_1280_PlanetX2.jpg?itok=1wE6ahlP

Weird Effects Of Gravity

Now, he has joined the search for new planets. His mysterious Planet X has ghostly gravitational effects suspected of altering the course of many heavenly bodies in our solar system.

Just last month, researchers claimed to have detected the faint microwave glow of an oversized rocky planet 300 AU away, using an array of telescope dishes called the Atacama Large Millimeter Array, or ALMA.

Sedna Changed History

Brown realized his problem in 2003, when he found Sedna. The orbits of a handful of space rocks had aligned for no apparent reason. Its odd orbit made it the most distant known object in the solar system at the time. Its perihelion, or closest point to the sun, lay at 76 AU, and far outside the influence of Neptune’s gravity. But the implication clearly indicates something massive has pulled Sedna into its distant orbit.

The final epiphany came 3 months ago, when Batygin’s simulations showed Planet X should also sculpt the orbits of objects swooping into the solar system to paths nearly orthogonal to the ecliptic. It turns out since 2002, five of these highly inclined Kuiper belt objects have been discovered, with their origins unknown. “Not only are they there, but they are in exactly the places we predicted,” Brown says. “That is when I realized that this is not just an interesting and good idea-this is actually real.”

Computer simulations from the California Institute of Technology reveal how the mystery planet would orbit between about 200 and 1,000 times farther from the sun than Earth.

Caltech says we should remember it takes this new planet between 10-20,000 years to make just one full orbit around the sun. The researchers, Batygin and Brown, originally discovered the planet’s existence through mathematical modeling and computer simulations. They know however, from other planetary perturbations, something is out there. They’re still waiting to observe the object directly.

Astronomers have some good ideas about where to look, but spotting the new planet will be difficult. Since planets in highly elliptical orbits move fastest when they are close to the sun, Planet X spends very little time at 200 AU. And if it were there right now, Brown says, it would be bright enough for astronomers to see.

Planet Nine (minus Pluto)

Nicknamed Planet Nine, it has a mass about 10 times that of Earth.

It’s harder to explain why Planet X never left the solar system. But Batygin says residual gas in the protoplanetary disk could have exerted enough drag to slow the planet for it to settle into a distant orbit and remain in the solar system. That likely happened when the solar system was between 3-10 million years old before gas in the proto-planet was lost into space.

But the 8meter Subaru telescope in Hawaii has enough light-gathering area to detect such a faint object. Its huge field of view is seventy-five times larger than the Keck telescope. Batygin and Brown are using the Subaru to look for Planet X, and coordinating efforts with competitors Sheppard and Trujillo, who have also joined the hunt. Brown says it’s going to take at least 5 years for the two teams to search the area for Planet X.

As can be seen from the above photograph, the elongated orbit around earth takes ~10,000-20,000 years. Obviously, it’s quite probable the sentient human race was never around for any kind of view of Planet Nine (X). In fact, it may be entirely possible for other unnamed proto-planets to be out at that distance we have no knowledge of – yet.

Kevin Roeten
A former Chemical Engineer, Kevin Roeten enjoys riding the third rail of journalism: politics and religion. He is a Guest Columnist for the Asheville Citizen-Times, and the Independent (Ohio), writes for numerous blogs, is an amateur astronomer, and delves into scientific topics.