Caltech Researchers Discover Evidence of a Ninth Planet

Posted on January 20, 2016

Planet Nine

Caltech researchers say they have discovered evidence that there is a ninth planet. The planet, dubbed Planet 9, is expected to have a mass 10 times that of the Earth and 5,000 times the mass of Pluto.

Planet 9 orbits the sun about 20 times farther from the sun on average than does Neptune. The researchers say it would take Planet 9 between 10,000 and 20,000 years to complete one full orbit around the sun.

Planet Nine has not been directly observed. Caltech researchers Konstantin Batygin and Mike Brown used mathematical modeling and computer simulations to determine its existence.

Planet Nine orbit diagram

Brown, the Richard and Barbara Rosenberg Professor of Planetary Astronomy at Caltech, says in a statement, "This would be a real ninth planet. There have only been two true planets discovered since ancient times, and this would be a third. It's a pretty substantial chunk of our solar system that's still out there to be found, which is pretty exciting."

Batygin says, "For the first time in over 150 years, there is solid evidence that the solar system's planetary census is incomplete."

The researchers say a ninth planet helps explain the alignment of distant Kuiper Belt objects and provides an explanation of orbits like Sedna. A research paper on the discovery was published here in the Astronomical Journal.

Science magazine also provided a video about the possible new planet and why the researchers strongly believe Planet 9 is out there. Scientists have been wondering about a "Planet X" for decades and now it appears very likely to exist. Take a look:

Top Image: Caltech/R. Hurt (IPAC)

Diagram: Caltech/R. Hurt (IPAC)

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