Perhaps God parked heaven in one galaxy and hell in another. The universe is certainly big enough that it could be some place where we have not looked.
Perhaps heaven and hell are in distinct universes. For those “scientists” (or others) who believe in an infinite number of universes, surely one is hell and another heaven.
Perhaps hell is for small people, who become smaller yet before entering. Hell may be a very small place. Hell may be someplace in your dog's chew toy.
The possibilities are endless.
The probability of intelligent life existing anywhere in the universe is indistinguishable from zero. Yet here we are.
I was not responding to the title question, but to the first sentence:
“Except in biblical or other written religious accounts, no scientific evidence has ever been documented to prove that there is a physical Heaven or a physical Hell.”