please help A christian has stumped me on this one.

[Angrboda]

It's not entirely clear what you mean by, "so astronomical that it just cannot happen," but it sounds like the typical "even if you rolled the dice a million times a second, it would take a million times the potential age of the universe to occur just once" sort of probability (Ala Dembski's 1.0x10^-150 upper limit). First off, this is a misunderstanding of basic probability. No matter how slim the odds of the winning ticket in a lottery being the first ticket purchased, there is nothing in physics or math to prevent it from happening. Sometimes, these odds are interpreted as, "on average, it would take N zillion zillion zillion years." But we don't care how long "on average" (which is a frequentist interpretation of probability, applied over a series of trials); we want to know if it happened at all. And there is nothing so improbable that it can't happen, unless it's impossible; and that's a different number. (There's a related mistake, basically the inverse, that suggests that if an event is sufficiently probable, then it's certain to happen. No. Probable never leaps the gap to certain, no matter how probable.) Moreover, if you're calculating probability in reference to the universe as a whole, even defining probability becomes problematic. (Or I should say, "more problematic," as it's not fish in a barrel in every day probability, either.)

A man walking along a street is killed by a tile blown off a roof by the wind. We attribute this ... to the operation of blind natural laws and forces, without any special design on the part of anyone. Yet the chances against that event happening were almost infinite. The man might have been, at the moment the tile fell, a foot away from the spot on the sidewalk on which the tile fell, or two feet away, or twenty feet away, or a mile away. He might have been at a million other places on the surface of the earth. Or the tile might have fallen at a million other moments than the moment in which it did fall. Yet in spite of the almost infinite improbability of that happening, we do not find it necessary to suppose that someone threw the tile down from the roof on purpose .. We are quite satisfied to attribute the event to ... the operation of natural forces.

— H.T. Stace, quoted in Atheism: The Case Against God, George H. Smith.