Planet 9 January 21, 2016Posted by aquillam in Astronomy, MichiganAstro.
Tags: #planet9 #planetx
With a mass 10 times greater than Earth’s mass, it falls into that region of super Earth to Neptune sized planets. Regardless of whether it is a big terrestrial planet size or small gas giant size, it’s certainly big enough to have cleared its orbit, so it’s definitely a planet (though way out there, it’s probably not a terrestrial or jovian.)
It “orbits about 20 times farther from the sun on average than does Neptune.” Neptune is about 30 times farther from the Sun than Earth. That puts Planet Nine out at about 600 astronomical units! That is so far out, that the sun looks like nothing more than a bright star. And those planets we can see in our morning sky right now? An observer on Planet Nine wouldn’t be able to make them out all because they’re too close to the sun.
Here is a simulation of the sun and sky from Planet Nine using Starry Night software.