Russell Kirk had a devotion to the Shroud of Turin. I find the whole thing utterly fascinating. And so does Fr. Spitzer. If you're curious to know what kind of cosmic radiation (my phrase) could form that image, check out the Shroud information at the Magis Center.
I need to spend more time at the Magis Center website. It has lots of great stuff. It's largely science-driven, and science is emphatically not among my areas of knowledge, but based on what I've seen, even a scientific lunkhead like me can appreciate its content.