AKIPRESS.COM - There might be a ninth planet in the solar system after all, and it is not Pluto.

Two astronomers reported on Wednesday that they had compelling signs of something bigger and farther away — something that would satisfy the current definition of a planet, where Pluto falls short.

“We are pretty sure there’s one out there,” said Michael E. Brown, a professor of planetary astronomy at the California Institute of Technology, reports New York Times.

What Dr. Brown and a fellow Caltech professor, Konstantin Batygin, have not done is actually find that planet, so it would be premature to start revising mnemonics of the planets.

In a paper published in The Astronomical Journal, Dr. Brown and Dr. Batygin laid out a detailed circumstantial argument for the planet’s existence in what astronomers have observed: a half-dozen small bodies in distant elliptical orbits.

What is striking, the scientists said, is that the orbits of all six loop outward in the same quadrant of the solar system and are tilted at about the same angle. The odds of that happening by chance are about 1 in 14,000, Dr. Batygin said.

A ninth planet could be gravitationally herding them into these orbits.

For the calculations to work, the planet would be at least an equal to Earth, and most likely much bigger — perhaps a mini-Neptune, with a small but thick atmosphere surrounding a rocky core and mass about 10 times that of Earth. That would be 4,500 times the mass of Pluto.

Pluto, at its most distant, is 4.6 billion miles from the sun. The potential ninth planet, at its closest, would be about 20 billion miles away; at its farthest, it could be 100 billion miles away. One trip around the sun would take 10,000 to 20,000 years.