So, yesterday I found an invisibility cloak in my attic. It's got an instruction manual with it, and there it was mentioned that it is truly an invisibility cloak: it bends the light (actually, all electromagnetic radiation) around the wearer so that absolutely nothing can detect the wearer when looking at them.
Of course, I tried it on. And from what I could see of myself in the mirror, I was really invisible. It didn't even have the slight lag my previous invisibility suit (a chamaeleon suit) had in imitating the surroundings.
Then I realized: If the suit is bending the light around me -- how come I am not blind when wearing the thing?
My conclusion: It must let some photons through, ideally only those that will hit my retina to produce a picture in my brain. Things look exactly the same, whether I am wearing the cloak or not, so it can't let only a partial amount through.
But then, those photons that hit my retina can't be bent around me anymore to show the original picture. They're gone in a photochemical reaction.
So: what do I look like from behind? Do I show:
- two floating black spots that are the size and orientation of my retinas?
- two floating red spots (same as above) since my retinas have got blood in them and so should look red and not black?
- An area around the height my eyes would be that is slightly darker than normal, but no black spots because of interference and light scattering? (i.e. surrounding photons make up for some of the lack of those my eyes absorb, but of course, cannot compensate for all of it)
- Or is the number of photons my eyes absorb so minimal that nothing can be detected at all?