Planet Nine

Scientists seem to have found new evidence about the existence of a ninth planet way out past Pluto's orbit. The planet should be huge and take around 11,000 years to go around the once!!

Astronomers at the California Institute of Technology announced Wednesday that they have found new evidence of a giant icy planet lurking in the darkness of our solar system far beyond the orbit of Pluto. They are calling it "Planet Nine." 

Their paper, published in the Astronomical Journal, estimates the planet's mass as five to 10 times that of the Earth. But the authors, astronomers Michael Brown and Konstantin Batygin, have not observed the planet directly. 

Instead, they have inferred its existence from the motion of recently discovered dwarf planets and other small objects in the outer solar system. Those smaller bodies have orbits that appear to be influenced by the gravity of a hidden planet – a "massive perturber." The astronomers suggest it might have been flung into deep space long ago by the gravitational force of Jupiter or Saturn. 

Telescopes on at least two continents are searching for the object, which on average is 20 times farther away than the eighth planet, Neptune. If "Planet Nine" exists, it's big – about two to four times the diameter of the Earth, which would make it the fifth-largest planet after Jupiter, Saturn, Uranus and Neptune. But at such extreme distances, it would reflect so little sunlight that it could evade even the most powerful telescopes.
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The thought of a hidden planet larger than Earth is intriguing, but for now it's difficult to say too much about the hypothetical conditions there. Brown believes it's probably an icy, rocky world with a small envelope of gas – a planet that could have been the core of a gas giant had it not been ejected into a wonky, highly elliptical orbit. It might not make its closest approach of the sun more than once every 10,000 years, and even then it would remain far beyond the known planets. 

The situation mimics what happened in the 19th century when careful observation of the seventh planet, Uranus, indicated that there must be another body in far-distant space influencing its orbit. That work led eventually to the discovery of Neptune.

How cool would it be to have visual confirmation of its existence!

There's more at The Washington Post.