Arguments against Christianity via Science

Yeah, I have been not liking religion for a long time, but recently I befriended a highly religious Christian friend that was open to discussion

The problem is: I seem to think that whatever I try to refute him with is wrong, and my own experience with science and the natural study of everything is too small to make an accurate refrence as to how Christianity is disproved

I brought in some bullshit about evolution and biology, but I failed horribly

So give me some proof that is irrefutable or otherwise widely used

I know there was another thread like this, but it didn't specifically address the question

If you are talking about using the elenchis, your question demonstrates that YOU'RE DOING IT WRONG.

If he says that his invisible sky monster is real, he is the one making the positive existential claim.  The burden of proof is upon him.  If he can't prove his deity is real, he loses.

It is of course impossible for him to prove much of anything at all within the structure of Thomas Aquinas's theology which is mostly stolen Platonism sprinkled with Aristotelianism with the serial numbers filed off.  Aquinas, in his fevered attempt to assume his conclusions, deliberately made all the central tenets non-disprovable and therefore non-testable.  Popper has demonstrated that a non-testable claim is meaningless noise and conveys no information.  Therefore you win.  But if you're a dick about it he won't be your friend much longer.  Then again, do you want a christfag for a friend?