#9 may be Out There

[BaalChatzaf]

There is some solid evidence that a -real- ninth planet about 10 earth masses may be way out in the Kuiper Belt.

Please see https://www.caltech.edu/news/caltech-researchers-find-evidence-real-ninth-planet-49523

Spotting this possible planet and getting an orbit will be quite difficult.   Here is an illustration of possible orbits:  

Two major planets were determined to exist because of the gravitational effects they had on known planets (Uranus and Neptune). This latest may be the third such major planet discovered in our solar system.  Time will tell.

Pluto was demoted from being a planet because it did not have enough mass to clear its orbit of smaller bodies. If Pluto were still defined to be a planet then there would be tens of thousands more planets out in the Kuiper Belt.  So it was demoted for book keeping reasons. 

Edited April 12, 2016 by BaalChatzaf
added illustration

[Peter]

Fascinating. The new mass could be building material for sentient, space going beings. Or a stopover for r and r and exploration. I am all for knocking off course the Earth's next scheduled (by happenstance and gravity) asteroid strike.

Peter