CAPE CANAVERAL, Fla. — The solar system may have a ninth planet after all.
This one is 5,000 times bigger than outcast Pluto and billions of miles farther away, say scientists who presented “good evidence” for a long-hypothesized Planet X on Wednesday.
The gas giant is thought to be almost as big as its nearest planetary neighbor, Neptune, quite possibly with rings and moons. It’s so distant that it would take 10,000 to 20,000 years to circle the sun.
Planet 9, as the pair of California Institute of Technology researchers calls it, hasn’t been spotted yet. They base their prediction on mathematical and computer modeling, and anticipate its discovery via telescope within five years.
The two reported their research Wednesday in the Astronomical Journal because they want people to help them look for it.
“We could have stayed quiet and quietly spent the next five years searching the skies ourselves and hoping to find it. But I would rather somebody find it sooner than me find it later,” astronomer Mike Brown told The Associated Press.
“I want to see it. I want to see what it looks like. I want to understand where it is, and I think this will help.”
Brown and planetary scientist Konstantin Batygin feel certain about their prediction, which at first seemed unbelievable to even them.
“For the first time in more than 150 years, there’s good evidence that the planetary census of the solar system is incomplete,” Batygin said, referring to Neptune’s discovery as Planet 8.
Once it’s detected, Brown insists there will be no Pluto-style planetary debate. Brown ought to know; he’s the so-called Pluto killer who helped lead the charge against Pluto’s planetary status in 2006. Once Planet 9, Pluto is officially considered a dwarf planet. “THIS is what we mean when we say the word ‘planet,’ ” Brown said.
Brown and Batygin believe it’s big — 10 times more massive than Earth — and unlike Pluto, dominates its cosmic neighborhood. Pluto is a gravitational slave to Neptune, they pointed out.
Another scientist, Alan Stern, said he’s withholding judgment on the planet prediction. He is the principal scientist for NASA’s New Horizons spacecraft, which buzzed Pluto last summer in the first-ever visit from Planet Earth. He still sees Pluto as a real planet — not a second-class dwarf.
“This kind of thing comes around every few years. To date, none of those predicts have been borne out by discoveries,” Stern said in an email Wednesday. “I’d be very happy if the Brown-Batygin were the exception to the rule, but we’ll have to wait and see. Prediction is not discovery.”
Brown and Batygin shaped their calculation on the fact that six objects in the icy Kuiper Belt, in the far reaches of the solar system, appear to have orbits influenced by only one thing: a real planet. The vast, mysterious Kuiper Belt is home to Pluto.
Brown discovered one of these six objects more than a decade ago — Sedna, a large minor planet.
“What we have found is a gravitational signature of Planet 9 lurking in the outskirts of the solar system,” Batygin said. The discovery, he noted, would be “era-defining.”