I was talking to my dad about it yesterday and we were wondering if seeing "auras" is really seeing infra-red. We usually regard the visible spectrum as red-violet (i.e. the rainbow) but we know there are some people who can hear higher and lower frequencies than is normal for a human, so it stands to reason that there will be some people who can see a little into infra-red or ultra-violet. Infra-red cameras will usually show heat density, and it's probable that the reason we see only re-violet is that that tells us most accurately about the physical world. Like if you were walking about on the roof of a building and saw in infra-red you might fall off by walking out onto a thermal of heatloss coming from inside, or walk all round what looks like a big hole but is in fact an area of particularly well-insulated roof.

Bx