Sat, Oct 22, 2016 - Page 6 News List

Research hinting at ninth planet presented

The Guardian, SAN FRANCISCO

Astronomers on Wednesday presented new research on the possibility of a gigantic, unseen planet beyond Neptune, saying the hypothetical world might have set the solar system at a tilt.

Researchers first suggested a massive ninth planet in January, saying that although this putative world would be about 10 times the size of Earth, it could have escaped a telescope’s notice because of its extreme distance from the sun.

According to their calculations, one year on this planet would last 17,000 years on Earth, and it would travel as far away as 150 billion kilometers from the sun, where it would take light a week to arrive.

Astronomers at the California Institute of Technology presented new evidence at the annual meeting of planetary scientists of the American Astronomical Society in Pasadena.

“The search for planet nine is as much about understanding the effects of planet nine on the solar system, the physics of planet nine, as it is about understanding where it is,” Caltech astronomer Mike Brown said.

Brown said that his team had calculated how a hypothetical planet could be responsible for making the sun appear to tilt at an angle.

Though the eight planets orbit in an essentially flat plane around the sun, the plane itself rotates at nearly a six-degree angle, making it look like the sun itself is angled. A giant planet with a strange orbit, about 30 degrees off the other planets’ plane, could account for that wobble, the scientists said.

“Because planet nine is so massive and has an orbit tilted compared to the other planets, the solar system has no choice but to slowly twist out of alignment,” said Elizabeth Bailey, the study’s author.

“It’s such a deep-rooted mystery and so difficult to explain that people just don’t talk about it,” Brown said.

“If you ask yourself where the sun is tilted in real life, there’s where we predict it should be,” he added, adding that the calculations of mass and orbital angle had results of six degrees.

“The amazing thing is for these very standard [observations] it tilts it nearly exactly correctly,” Brown said. “At this stage we have so many lines of evidence that there’s a massive planet out there that if there’s not a massive planet out there, it has to be that there was one there yesterday and disappeared.”

Brown suggested that scientists might be able to locate the planet, if it exists, in the next few years, and that his team’s work would be published in an upcoming issue of the Astrophysical Journal.

Another team of researchers, led by the University of Arizona’s Renu Malhotra, also shared new research suggesting a hypothetical planet, but said that it was by no means proof of the world.

They found that the four objects with the longest-known orbits in the Kuiper Belt, a ring of rocks and dwarf planets, would be most easily explained by a mammoth new planet.

These “extreme” Kuiper Belt objects, which have highly elongated orbits around the sun, have “very simple orbital ratios [suggesting] they are in resonances with an unseen massive planet,” Malhotra said.

Brown and Malhotra both said that there are reasons to be skeptical, despite the former’s optimism for discovery.

“There are observational biases all over the Kuiper Belt,” Brown said. “We always worry about them. We don’t think they’re affecting results.”

Massachusetts Institute of Technology-trained Walt Brown told the Taipei Times in January that a ninth planet would not be found to be causing the correlation of the Kuiper Belt objects.

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