|Photo via Bits and Pieces (I think)|
I do hope that the image on your right is real and not 'shopped. It's rather amazing, if it's real (and why wouldn't it be?).
As I've discussed on more than one occasion, the effect is known as pareidolia. Our eyes and brains have been genetically pre-programmed to recognize patterns, particularly own mother's faces. And we continue to recognize faces, even when we aren't actually looking at a face. I posted this picture on Facebook and sweet, crazy Mia immediately commented: "I see Jesus! It's Jesus!"
But imagine being a primitive version of yourself, living 8 to 10 thousand years ago. You have no knowledge of science and the natural world seems a very magical place (which it is, but in a very different sense). You're out with some of your buddies, gathering wood for a fire to cook tonight's mastodon when you come upon the face of what must obviously and undoubtedly be the snow god, himself. You may pause to marvel, but you can bet your hairy caveman ass you'll be bowing and backing away in fear and reverence. Is it any wonder that mythology is filled with Green men; fairies; elves; satyrs; centaurs; naiads and dragons? Happy Place has a great post of 'The Most Absurd Objects Jesus Has Ever Appeared On" that more fully illustrates one of the more common themes in pareidolia.
The truth is, religion is like magic. And magic is only what science doesn't understand, yet. There are no fairies; elves; centaurs or dragons. The snow on that tree just happened to lay/melt in a pattern that resembles a face; a pattern we are genetically predisposed to recognize. The magic is in the physics that caused the snow to lay/melt or whatever in that pattern and the biology that allows to see a face in a random pattern. Our brains are wired to to try and make sense out of visual patterns. We can't help but see things that aren't really there.
Speaking of invisible (the only segue that makes any sense at all), here's a Forgotten Gem from my childhood:
When you're 8, the only thing scarier than a monster you can't see is a monster brain that you can.