| California Institute of Technology

California astronomers set to search for possible ninth planet

Later this month, two astronomers from the California Institute of Technology will go on a hunt for a massive planet that their research indicates may lie on the icy edge of our solar system.

Mike Brown and Konstanin Batygin will be reviewing data from the Subaru Telescope, located at the summit of Mauna Kea in Hawaii, as the telescope scans a section of sky for the elusive object dubbed “Planet Nine.”

The sky search will be the culmination of years of theoretical study and research by the two astronomers into the unusual orbital movements of objects in the Kuiper Belt. That’s the distant part of our solar system beyond the orbit of the planet Neptune, where Pluto, comets and other icy objects can be found.

Brown’s research into this region eventually led to the demotion of Pluto – once classified as the ninth planet in the solar system – to a dwarf planet. The International Astronomical Union made that decision in 2006, after the discovery of an astronomical body larger than Pluto in those outer reaches.

Batygin’s computer modeling of Kuiper Belt objects showed their orbits, all pointing outward in roughly one direction, showed that an unknown gravitational force must be shepherding the objects’ movements.

“This means there’s a strange coincidence, or else something is keeping them lined up,” Brown told AMI Newswire.

Brown, whose Twitter handle is @plutokiller, said the scientists tried to investigate other possible explanations other than a ninth planet, but they eventually concluded that a large planet – 10 times the mass of Earth – must be the culprit.

“Doing the theoretical research has been just tremendously fun,” he said. “But when we actually spot it, that will be the high point.”

Brown also hypothesizes that the planet is a gas giant, similar to Neptune, rather than a solid icy and rock world. That’s because many discoveries of so-called exo-planets orbiting other stars are about this size, and they are almost always gas giants, he said.

“It’s probably quite reflective and quite bright,” Brown said. It has yet to be discovered, however, because it sits on the cusp of what some of the most powerful telescopes can see.

Planet Nine is estimated to be 20 to 30 times farther away than Neptune and takes an estimated 20,000 years to orbit the sun, Brown said. It’s possible that the planet was “captured” by the sun from a neighboring star, but a more probable theory is it was created during the formation of the solar system and got pushed outward into its far-away orbit.

Brown said there’s no question that Planet Nine fits the current definition of a planet, because it would be the most massive object ever found in that part of the solar system and would clearly dominate its orbit around the sun.

Jim Green, director of NASA’s Planetary Science Division, said earlier this year that although the research by Brown and Batygin is certainly exciting, there is reason to be cautious.

“This is not … the detection or discovery of a new planet,” Green said. “It’s too early to say with certainty there’s a so-called Planet X. What we’re seeing is an early prediction based on modeling from limited observations.”

In a previous recorded interview, Batygin said, “What we have is a gravitational signature of the existence of this planet.”
 
Brown said that many of his colleagues in the astronomy community are excited about the possibility of a new planet, but some have expressed skepticism.

“Scientists love to shoot each other’s theories down,” he said. “People who understand the computer simulations we did are the ones who are the most convinced.”

Of course, actually sending a probe to Planet Nine, if its discovery is confirmed, will take time. But Brown has been talking with a group at NASA’s Jet Propulsion in Pasadena, Calif., about ways to develop an ultra-fast probe to reach Planet Nine.

“The trick to going fast is to use a gravitational sling shot,” he said. Launching a craft toward the sun and then using the solar gravitation to accelerate it to a high speed toward the outer solar system might result in a craft arriving at the planet in about 30 years.

By comparison, the New Horizons craft that took pictures of Pluto during a fly-by last year took 10 years to reach its target, although Pluto is 20 times closer to Earth than Planet Nine.

There’s no actual protocol for the naming of a new planet, and Brown said he has not thought of a possible name yet for fear of jinxing the search. But he speculates the two astronomers would be allowed to name it – provided the name was “not ridiculous.”

However things play out in the month ahead – the Hawaii telescope will be searching for the new planet from Sept. 26 to Sept. 29 and on Oct. 3 and Oct. 4 – Green, the NASA planetary scientist, said people interested in astronomy will have a front-row seat in seeing how the scientific process plays out.