Ah, yes, the great extraterrestrial golden peril! Fear his mercilessness! Fear being blinded by him crossing a stray sun-ray!
As for Planet 'X', my mind strains to imagine the shear volume of space that is being searched for what is essentially a needle in a VERY LARGE haystack. While Tombaugh's discovery of Pluto was the results of very painstaking effort, the actual reason for the search was to find 'X' and Pluto was far too small for the effects known. What will be discovered is far more than what has been discovered, we just don't know it yet!
Stop! You're scaring me. lol
...my mind strains to imagine the shear volume of space that is being searched...
That's true. Usually we just boggle our minds with incredible linear numbers like how far it is and how long it might take to get from Point A to Point B in space. But cubic miles in an ever growing spherical search grid around a star? Each mile further in radius is a tremendously larger volume than the mile before it.