New planet discovered at the edge of the solar system

Posted Jan 21, 2016 by Stephen Morgan
Scientists are virtually sure they have found a new planet at the outer edge of our solar system. Sometimes called Planet X or Planet Nine, it is believed to be lurking in the little-known Kuiper belt far beyond Pluto.
Artist s image of the distant view from Planet Nine back towards the sun
Artist's image of the distant view from Planet Nine back towards the sun
Caltech/R Hurt (IPAC)
The centuries-old hunt for the "lost world" at the edge of our solar system seems to have finally come to an end. Pain-staking calculations of strange astronomical phenomena far beyond the orbit of Pluto, suggest that the only explanation for these irregularities must be an unknown planet.
Not only that, but it would be a massive object, calculated to be four times the size of Earth with ten times its mass. It has remained undetected because of its enormous distance from the rest of the solar system and the limited light it gives off.
The Guardian reports that, "it moves on an extremely elongated orbit, and takes a staggering 10,000 to 20,000 years to swing once around the sun."
"The closest it comes to the sun," says the paper, "is 15 times the distance to Pluto. It then heads into uncharted territory, 75 times further out than Pluto, or about 93 billion miles from the sun. A ray of light would take a week to get there."
What grabbed the attention of astronomers was the strange behavior of 13 objects in the Kuiper belt — a region of icy objects such as comets, asteroids and dwarf planets like Pluto.
“We saw a strange signal in the data that meant something odd was going on in the outer solar system,” said Mike Brown, from the California Institute of Technology (Caltech). “All of these distant objects were lined up in a weird way and that shouldn’t happen."
They found that six of these objects moved together in an orbital alignment at the same angle of all the other known planets in our solar system.
“If you looked down on the solar system and had the sun in the center, all of these objects would head out to the 9 o’clock position,” said Brown.
The scientists first looked for run-of-the-mill explanations for this phenomenon, and actually began their research by setting out to disprove speculation that there might be an undiscovered planet. Indeed, Brown is known as more of a planet debunker, than one inclined to pursue hypothetical ideas.
In his book, "How I Killed Pluto", he recounts the key role he played in getting Pluto thrown out of the list of planets in the solar system, by demoting it to the status to that of a dwarf planet.
Moreover, Brown was one of the most skeptical critics of the results from research made only last month by scientists using the the Atacama Large Millimeter Array (ALMA) telescopes in Chile, who said they had detected a dim microwave glow from a large planet on the edges of the solar system.
When data this month tended to back this up, Brown and his colleague, Konstantin Batygin, began looking for different explanations, such as the influence of a star or that the Kuiper belt was so dense that the combined gravitational effect could be causing the unusual alignment of objects they observed. But the more they explored mundane reasons, the closer they came to the idea that another planet was causing it.
Eventually, they're simulations appeared to prove that only the existence of a huge planet in an extremely unusual orbit could cause the alignment of these other objects in the Kuiper belt. “When we found that, my jaw sort of hit the floor,” said Brown.
Unusual orbit of Planet X or Planet Nine
Unusual orbit of Planet X or Planet Nine
How such a planet could have got there is probably the result of the huge gravitational power of Jupiter and Saturn during the chaotic processes at the beginning of the formation of our solar system. Science magazine explains;
"Computer models have shown that the early solar system was a tumultuous billiards table, with dozens or even hundreds of planetary building blocks the size of Earth bouncing around. Another embryonic giant planet could easily have formed there, only to be booted outward by a gravitational kick from another gas giant."
National Geographic says that Brown and Batygin, "suspect the planet formed much closer to the sun and was launched outward when the solar system was very young. Back then.....the sun was still snuggled into its native stellar cluster, and the surrounding stars would have helped corral the flying planet and kept it from escaping the clutches of the sun’s gravity."
The search for Planet X goes way back to 1846, when French astronomer Urbain LeVerrier discovered Neptune, but was unable to explain irregularities in its orbit, recounts the Smithsonian.
Similarly strange perturbations in Uranus' orbit led some astronomers to speculate that there could be another planet. Pluto was later discovered, but its small size couldn't account for the effects on Neptune and Uranus. The controversy has continued until the present day, but with most scientists remaining skeptical of its existence.
However, commenting on the new findings, Chris Lintott, a professor of astrophysics at Oxford, said that "this is the most detailed and most convincing analysis” for the existence of an undiscovered planet at the edge of our solar system.
As is always the case with new and controversial discoveries, there are still doubts about Brown and Batygin's results, and, undoubtedly, it will lead to a flurry of new research papers.
Absolute confirmation of its existence will depend on more concrete observations of the object, not least by telescopes. But this will not be easy. Science Magazine explains that;
"Most telescopes capable of seeing a dim object at such distances, such as the Hubble Space Telescope or the 10-meter Keck telescopes in Hawaii, have extremely tiny fields of view. It would be like looking for a needle in a haystack by peering through a drinking straw."
However, the publication adds that, "one telescope can help: Subaru, an 8-meter telescope in Hawaii that is owned by Japan. It has enough light-gathering area to detect such a faint object, coupled with a huge field of view."
The New Scientist quotes Brown as saying;
“All those people who are mad that Pluto is no longer a planet can be thrilled to know that there is a real planet out there still to be found. Now we can go and find this planet and make the solar system have nine planets once again.”