The new horizons space probe as it approaches Pluto.

It looks like we have nine planets again.  Researchers at Caltech say it's a giant planet and they've named it Planet Nine.  Scientists say they haven't actually seen it, but they discovered its existence through mathematical modeling and computer simulations. 

This is only the third planet to be discovered since ancient times.  Caltech officials say Planet Nine is ten times more massive than Earth and orbits the sun about 20 times farther out than Neptune.  They say it would take between ten-thousand and 20-thousand years to make one trip around the sun.  

The newly-discovered object takes Pluto's place in our galaxy of planets.  Pluto was demoted to dwarf planet status.  A Caltech spokesman says that "for the first time in over 150 years, there is solid evidence that the solar system's planetary census is incomplete." 

Mike Brown from CalTech, called into KFI, in Los Angeles to discuss the discovery.

Photo: Getty Images

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