They, of course, did nothing of the sort. In terms of my suggested computation, they picked one back-vector out of countless trillions of the back-in-time computations that would be required to examine the universe exhaustively. As they say, it's not that you're right; it's not that you're wrong. It's that you aren't even in the game.
Actually -- since we have an rough estimate of the size and age of the universe and provided for a very generous margin of error -- there isn't "countless trillions." Which is the point of the calculations.