Thank you for your honesty...but you first said ‘incontrovertible’. I have looked and found much speculation, but no evidence derived from methodological science.
It may well be the "answer to everything" ~ unfortunately.
This is postulated to be a partial explanation for the discovery that the universe is expanding an accelerating rate.
So, what's "over the horizon" outside of our universe?
Could it perhaps be "another universe"?
Gotta' be something!