I don't know if it's possible to imagine what it was like for people living around the year 1500. To believe that the Earth is literally the center of the Universe. That the Universe exists, clearly, to entertain we poor Earthlings, and that the stars provide an occasional look into the realm of God himself. Can you imagine what it was like to discover that the Earth was the center of nothing? That humans had absolutely no significance on the cosmic scale? I can't.
Today, we're used to the idea of being a random planet in a boring part of a middling galaxy, so a faith developed today casually accepts this unimportant role. At the time, I imagine that many people's faiths were threatened.
The only other revelation as powerful as that one is the Theory of Evolution. Although various evolutionary theories had been floating around before Darwin's, His was so elegant, so obviously true, that it left little necessity for any Divine figure in a creation story. All evolution needs is a single self-replicating chemical.
Today, people grow up with Evolution coloring all Biology. At the time of Darwin, a lot of the Bible was literal. Since then, Metaphor has replaced basically any part of the Bible that isn't purely theological. Without the knowledge that their sacred texts were "only kidding", it must have been traumatic to find that there was no basis for the idea that species had spontaneously arisen from the Universal Will.
I don't think it's possible to create a psychic shock like that again. Einstein's Theory of Relativity is extremely important to science, and redefines our world view, but few religions explicitly require travel at the speed of light to be possible. Quantum Theory says that a Quantum switch's results don't occur until they are checked. This can lead to some sticky theological issues, (does God wait until the waveform collapses to collect the soul of that poor cat?) but it hardly challenges our assumptions about Quantum switches. After all, we didn't have any assumptions about them. Hell, we still don't know what they are.
Now playing: Edwin Starr - War [What is it good for]