Here's what's incomprehensible scientifically: a Creator who makes everything we see in just a few "days", but giving it all the appearance of being many billions of years old.
There's no rational explanation for that, so Occam's Razor tells us the better explanation is that the Universe is what it appears to be: many billions of years old.
Chew on this (I’m contemplating the implications):
Vestigial light (aka “background microwave radiation”) emitted near the Big Bang and just reaching us now has experienced _zero_ time along the trip. From that photon’s perspective, there is no distance from that early explosion to your eye. Firmly scientific, and firmly messing with the notion of mere days vs billions of years.
(I’m not saying the above disproves either side. Methinks it opens the possibility of rectifying the apparent differences. Until I can work out the implications, I’m holding that the universe is, in fact, billions of years old - and what we plainly see doesn’t fit in a 10,000 year Creationist (capital “C”) model.)