Astronomers Find Evidence of a Ninth Planet of the Solar SystemBy Russell Westerholm
When Pluto was identified as a dwarf planet the solar system no long had nine planets, but there may be a new candidate to fill that void.
Published in The Astrophysical Journal, the new study described a gas giant called "Planet 9" that technically has yet to be spotted. Based on computer models, the true ninth planet of the solar system is likely to exist and will take astronomers five years at the most to find 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," Mike Brown, an astronomer at the California Technical Institute, 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."
Planet 9 is believed to be a little smaller than Neptune and would orbit the sun billions of miles farther than Neptune does. By Earth's standards, Planet 9 would complete a trip around the sun once every 10,000 to 20,000 years.
"Although we were initially quite skeptical that this planet could exist, as we continued to investigate its orbit and what it would mean for the outer solar system, we become increasingly convinced that it is out there," Konstantin Batygin, an assistant professor of planetary science at Caltech, said in a press release. "For the first time in over 150 years, there is solid evidence that the solar system's planetary census is incomplete."