How did scientists determine an estimate of the number of planets greater than Sedna's size to exist in the Inner Oort Cloud?
In the article, New Dwarf Planet Found at Solar System's Edge, Hints at Possible Faraway 'Planet X' (Wall, 2014) where they report on research and observations performed by astronomers that discovered ...
What reason is there to doubt the existence of the hypothesised planet Tyche in the far distant solar system?
Please note, I do not necessarily believe in its existence, just after a scientific (hence, non-Wikipedia) reasoning to doubt the planet's existence, other than the "we would have seen it" argument. ...