An aura or Human energy field is, according to New Age beliefs, a colored emanation said to enclose a human body or any animal or object. In some esoteric positions, the aura is described as a subtle body.Psychics and holistic medicine practitioners often claim to have the ability to see the size, color and type of vibration of an aura.
In New Age alternative medicine, the human aura is seen as a hidden anatomy that affect the health of a client, and is often understood to comprise centers of vital force called chakra. Such claims are not supported by scientific evidence and are pseudoscience. When tested under controlled experiments, the ability to see auras has not been shown to exist.
In Latin and Ancient Greek, aura means wind, breeze or breath. It was used in Middle English to mean "gentle breeze". By the end of the 19th century, the word was used in some spiritualist circles to describe a speculated subtle emanation around the body.
The concept of auras was first popularized by Charles Webster Leadbeater, a former priest of the Church of England and a member of the mystic Theosophical Society. Leadbeater had studied theosophy in India, and believed he had the capacity to use his clairvoyant powers to make scientific investigations. He claimed that he had discovered that most men come from Mars but the more advanced men come from the Moon, and that hydrogen atoms are made of six bodies contained in an egg-like form. In his book Man Visible and Invisible published in 1903, Leadbeater illustrated the aura of man at various stages of his moral evolution, from the "savage" to the saint. In 1910, Leadbeater introduced the modern conception of auras by incorporating the Tantric notion of chakras in his book The Inner Life. But Leadbeater didn't simply present the Tantric beliefs to the West, he reconstructed and reinterpreted them by mixing them with his own ideas, without acknowledging the sources of these innovations. Some of Leadbeater's innovations are describing chakras as energy vortexes, and associating each of them with a gland, an organ and other body parts.
In the following years, Leadbeater's ideas on the aura and chakras where adopted and reinterpreted by other Theosophists such as Rudolf Steiner and Edgar Cayce, but his occult anatomy remained of minor interest within the esoteric counterculture until the 1980s, when it was picked up by the New Age movement.
In 1977, American esotericist Christopher Hills published the book Nuclear Evolution: The Rainbow Body, which presented a modified version of Leadbeater's occult anatomy. Whereas Leadbeater had drawn each chakras with intricately detailed shapes and multiple colors, Hills presented them as a sequence of centers, each one being associated with a color of the rainbow. Most of the subsequent New Age writers will base their representations of the aura on Hill's interpretation of Leadbeater's ideas. Chakras became a part of mainstream esoteric speculations in the 1980s and 1990s. Many New Age techniques that aim to clear blockages of the chakras were developed during those years, such as crystal healing and aura-soma. Chakras were, by the late 1990s, less connected with their theosophical and Hinduist root, and more infused with New Age ideas. A variety of New Age books proposed different links between each chakras and colors, personality traits, illnesses, Christian sacraments, etc. Various type of holistic healing within the New Age movement claim to use aura reading techniques, such as bioenergetic analysis, spiritual energy and energy medicine.
There have been numerous attempts to capture an energy field around the human body, going as far back as photographs by a French army officer in the 1890s. Supernatural interpretations of these images have often been the result of a lack of understanding of the simple natural phenomena behind them, such as heat emanating from a human body producing aura-like images under infrared photography.
In 1939, Semyon Davidovich Kirlian discovered that by placing an object or body part directly on photographic paper, and then passing a high voltage across the object, he would obtain the image of a glowing contour surrounding the object. This process became known as Kirlian photography. Some parapsychologists, such as Thelma Moss of UCLA, have proposed that these images show levels of psychic powers and bioenergies. However, studies have found that the Kirlian effect is caused by the presence of moisture on the object being photographed. Electricity produces an area of gas ionization around the object if it is moist, which is the case for living things. This causes an alternation of the electric charge pattern on the film. After rigorous experimentations, no mysterious process has been discovered in relation to the Kirlian photography.
More recent attempts at capturing auras include the Aura Imaging cameras and software introduced by Guy Coggins in 1992. Coggins claims that his software use biofeedback data to color the picture of the subject. The technique has failed to yield reproducible results.
The book The Third Eye, written by Cyril Henry Hoskin under the pseudonym Lobsang Rampa, claims that Tibetan monks opened the spiritual third eye using trepanation in order to accelerate the development of clairvoyance and allow to see the aura. It also includes body gazing techniques purported to help achieve aura visualization. The book is considered to be a hoax.
Tests of psychic abilities to observe alleged aura emanations have repeatedly been met with failure.
One test involved placing people in a dark room and asking the psychic to state how many auras she could observe. Only chance results were obtained.
Recognition of auras has occasionally been tested on television. One test involved an aura reader standing on one side of a room with an opaque partition separating her from a number of slots which might contain either actual people or mannequins. The aura reader failed to identify the slots containing people, incorrectly stating that all contained people.
In another televised test another aura reader was placed before a partition where five people were standing. He claimed that he could see their auras from behind the partition. As each person moved out, the reader was asked to identify where that person was standing behind the slot. He identified 2 out of 5 correctly.
Attempts to prove the existence of auras scientifically have repeatedly met with failure; for example people are unable to see auras in complete darkness, and auras have never been successfully used to identify people when their identifying features are otherwise obscured in controlled tests. A 1999 study concluded that conventional sensory cues such as radiated body heat might be mistaken for evidence of a metaphysical phenomenon. 
Bridgette Perez in a review for the Skeptical Inquirer has written "perceptual distortions, illusions, and hallucinations might promote belief in auras... Psychological factors, including absorption, fantasy proneness, vividness of visual imagery, and after-images, might also be responsible for the phenomena of the aura."
Studies in laboratory conditions have demonstrated that the aura is best explained as a visual illusion known as an afterimage. Neurologists contend that people may perceive auras because of effects within the brain: epilepsy, migraines, or the influence of psychedelic drugs such as LSD.
Psychologist Andrew Neher has written that "there is no good evidence to support the notion that auras are, in any way, psychic in origin."
It has been suggested that auras may be the result of synaesthesia. However, a 2012 study discovered no link between auras and synaesthesia, concluding "the discrepancies found suggest that both phenomena are phenomenologically and behaviourally dissimilar." Clinical neurologist Steven Novella has written "Given the weight of the evidence it seems that the connection between auras and synaesthesia is speculative and based on superficial similarities that are likely coincidental."