In Paganism and many other spiritual paths the term “Aura” is taken to mean the energy field surrounding the human body. In sacred art Gods, Goddesses and holy people are frequently depicted with a head or full-body halo of colour, usually gold, purple, or blue, depicting the Divine energy surrounding them. In everyday conversation some people are said to have an “Aura of power” or an “Aura of mystery” about them. There are several types of aura which include optical illusion, projection of personal impressions, and actual perception of the human energy field around sentient and, some say, supposedly inanimate objects.

The biophysical explanation for seeing auras around things involves refraction within the lens of the eye, and at the corneal layer on the surface of the eye. It can also be the result of the way the retinal pigment works. The corneal layer of the eye is made up of clear skin cells that, under some circumstances, can cause light to refract slightly splitting it into colours in a way similar to a glass prism. This can be heightened by conditions such as astigmatism where the cornea is slightly oval shaped as opposed to the more usual round shape. This year a fourth layer of the cornea called “Dua's Layer” has been discovered that may also play a part in this type of effect. The Lens of the eye can also have refractive properties that can interfere with precision of vision, one of the most common of which is when the protein in it crystallises. This usually happens as part of the natural aging process, and is the main cause of cataracts in later life. But due to injury, genetics, and biological diversity it can happen sooner to some people and can cause a halo to be seen around objects, or superimpose a range of colours around and over what a person sees.

After passing through the cornea and lens, plus the liquids in the eye (Aqueous and Vitreous humours) the light arrives at the retina where a complex chemical and quantum mechanical process takes place. The retina is mainly made up of two types of cells, rods and cones, named after their shapes. Rods make up the bulk of the retina with the cones concentrated mainly in the central area. Rods are good at detecting shape and movement, and work well in low light situations. Cones are responsible for the colour in vision and are concentrated in the central area of the eye where the lens is focussed. Each cone has pigments in it that are sensitive to either red, green or blue which are stimulated when photons of that light frequency hit it. According to the theory of Trichromancy these three colours are able to make up the colours of the rest of the visible spectrum that most people see. This is how television and computer screens work.

The retina works using quantum physics principles, translating the different energies carried by light particles. Experiments have shown that this explains why the eye is unable to distinguish pure orange light from a mixture of red and yellow light which is only seen as orange. If the eye ‘saw’ light as a wave then it would be able to perceive the difference between the pure colour and the blend. For someone to see pure white light all three types of receptors need to be stimulated equally, differences in stimulation result in the production of colour vision. People who are colour blind have one or more of the types of cones non-functional or missing, possibly a throwback to earlier genetic ancestors when colour vision was a less important part of life.

Once the pigment has been produced continuing to stare at one colour, or images made up of predominantly one colour, can cause the eye’s cones can become overstimulated and temporarily lose sensitivity to it. This can lead to afterimages being perceived in the opposite primary colour to the one formerly being looked at if the person looks at a neutral area such as a blank piece of paper or a white or cream coloured wall or door. For example if you look steadily at a big picture of an all red boat, then switch your gaze to a white door you will usually see a green afterimage of the boat on the door. With a bright light such as a camera flash, or after looking at a candle flame for a while as in some forms of meditation or visualisation practice, you will see a glowing oil-film coloured afterimage for a short time as the overstimulated cones recover.

The final part of the physical plane phenomena that can cause auras and colours to be seen around people and objects lies in the nervous system itself. One of the most common reasons people see colours is due to a type of migraine called an “Aura Migraine” that, when it happens, causes shimmering patches of colour to be seen in the field of vision. Statistically approximately 8% of the population have this type of migraine which can also sometimes involve the area of the brain called the temporal lobe. This is very, very, rare even within the small proportion population mentioned but can give rise to full-blown hallucinations on occasion. The patches of colour previously mentioned are far more common and, insidiously, can happen with no other migraine symptoms – such as pain - so the person experiencing them can believe that they are seeing colours in reality rather than as part of a personal neural event.

Slightly more common is a phenomenon called ‘Synaesthesia’/‘Synesthesia’, or sensory crossover between any two senses. It is the source of people under the influence of drugs or suggestion reporting seeing sounds or smelling colours synaesthesia is both a learned and neurological condition and can happen without the person being aware of it. When I helped out at my friends Pagan shop in Portsmouth we decided that most, if not all, of the people who said they saw auras used a form of synaesthesia. In their case they picked up on a person’s body language, how they dressed and other subtle cues, and processed this into a synesthetic aura that they imagined surrounding that person. The colours they saw surrounding the body depended on the sort of person they imagined they were looking at, what sort of health they thought they were in, and the system of aura reading they had read about or were taught.

Having looked at the possible physical causes of why people may see auras around other people and objects, in the next article we can go on to explore some of the more esoteric based causes for being able to perceive the human energy field. Plus how it may be used in dowsing, healing, and its relationship to magick.