
Originally Posted by
Nowhere Man
Finally, just some comments, speaking as a decades-long reader and fan of science, science fiction, and fantasy.
Watch your apostrophes. Its and it's are different, as are lets and let's. Plurals never use apostrophes, unless you are pluralizing single characters (A's, B's, etc.). Possessives of singular nouns are always created by adding 's, even if the noun ends with s or an s-like sound. This and much more is all covered in The Elements of Style by Strunk and White, which I hope your writing instructors told you about.
As an SF fan, I bristle a bit at equating "absurdly impossible" with "science fiction." Science fiction is based on science (hence the name). Given the current state of knowledge, your scenario is fantasy, science fantasy at most. Back in the 30s, it would be science fiction. Nowadays, readers will generally let a writer get away with an impossibility or two (like FTL or psionics), if it advances the plot and (for me, anyway) is handled consistently and is not used as a deus ex machina to save the hero's bacon.
Consider how much exposition you need. The more you add, the more you give little seams and gotchas to readers that momentarily bump them out of the story, Enough, and they will eventually put the book down and not pick it up again.
Instead, how about you start with the discovery of your PX on the other side of the Sun, and periodically describe the turmoil it causes in the scientific community for the reasons that have been given in this thread, interleaved with the main thread of the plot. The origin story you gave here could be presented as one hypothesis.
Something like this can still be done well today. Consider Inherit the Stars by James P. Hogan, which is based on a discredited idea about the origins of the asteroids. Well done enough that the "oh brother" factor did not completely put me off the book.