The most nonsensical leap of faith I've ever heard of comes from the 'scientific' Big Banger theorists that claim an explosion or inexplicable force, apparently caused by absolutely nothing, originated and set into motion a boundless and perfectly harmonious universe. Jules Verne tipping on LSD couldn't even dream this nonsense up, though Timothy Leary might have believed it.
Ummmm.....
Exactly what Big Bang Scientists have claimed the universe is "perfectly harmonious?"
I seriously doubt you have the ability to even enter a discussion of the "boundless" issue (that is, the expanding universe is an expansion of space-time itself, so there isn't some border where you step "out" of the universe) so I won't even try.
And you can literally listen to the cosmic background radiation left over from the Big Bang. It's actual, real-world evidence.
The Big Bang appears in the Bible at Gen. 1:3.