Increasingly science agrees with the poetry of direct human experience: we are more than the atoms and molecules that make up our bodies, but beings of light as well. Biophotons are emitted by the human body, can be released through mental intention, and may modulate fundamental processes within cell-to-cell communication and DNA.
Nothing is more amazing than the highly improbable fact that we exist. We often ignore this fact, oblivious to the reality that instead of something there could be nothing at all, i.e. why is there a universe (poignantly aware of itself through us) and not some void completely unconscious of itself?
Consider that from light, air, water, basic minerals within the crust of the earth, and the at least 3 billion year old information contained within the nucleus of one diploid zygote cell, the human body is formed, and within that body a soul capable of at least trying to comprehend its bodily and spiritual origins.
Given the sheer insanity of our existential condition, and bodily incarnation as a whole, and considering that our earthly existence is partially formed from sunlight and requires the continual consumption of condensed sunlight in the form of food, it may not sound so farfetched that our body emits light.
Indeed, the human body emits biophotons, also known as ultraweak photon emissions (UPE), with a visibility 1,000 times lower than the sensitivity of our naked eye. While not visible to us, these particles of light (or waves, depending on how you are measuring them) are part of the visible electromagnetic spectrum (380-780 nm) and are detectable via sophisticated modern instrumentation.,
The Physical and "Mental" Eye Emits Light
The eye itself, which is continually exposed to ambient powerful photons that pass through various ocular tissues, emit spontaneous and visible light-induced ultraweak photon emissions. It has even been hypothesized that visible light induces delayed bioluminescence within the exposed eye tissue, providing an explanation for the origin of the negative afterimage.
These light emissions have also been correlated with cerebral energy metabolism and oxidative stress within the mammalian brain.  And yet, biophoton emissions are not necessarily epiphenomenal. Bókkon's hypothesis suggests that photons released from chemical processes within the brain produce biophysical pictures during visual imagery, and a recent study found that when subjects actively imagined light in a very dark environment their intention produced significant increases in ultraweak photo emissions. This is consistent with an emerging view that biophotons are not solely cellular metabolic by-products, but rather, because biophoton intensity can be considerably higher inside cells than outside, it is possible for the mind to access this energy gradient to create intrinsic biophysical pictures during visual perception and imagery.
Our Cells and DNA Use Biophotons To Store and Communicate Information
Apparently biophotons are used by the cells of many living organisms to communicate, which facilitates energy/information transfer that is several orders of magnitude faster than chemical diffusion. According to a 2010 study, "Cell to cell communication by biophotons have been demonstrated in plants, bacteria, animal neutriophil granulocytes and kidney cells." Researchers were able to demonstrate that "...different spectral light stimulation (infrared, red, yellow, blue, green and white) at one end of the spinal sensory or motor nerve roots resulted in a significant increase in the biophotonic activity at the other end." Researchers interpreted their finding to suggest that "...light stimulation can generate biophotons that conduct along the neural fibers, probably as neural communication signals."
Even when we go down to the molecular level of our genome, DNA can be identified to be a source of biophoton emissions as well. One author proposes that DNA is so biophoton dependent that is has excimer laser-like properties, enabling it to exist in a stable state far from thermal equilibrium at threshold.
Technically speaking a biophoton is an elementary particle or quantum of light of non-thermal origin in the visible and ultraviolet spectrum emitted from a biological system. They are generally believed to be produced as a result of energy metabolism within our cells, or more formally as a "...by-product of biochemical reactions in which excited molecules are produced from bioenergetic processes that involves active oxygen species," 
The Body's Circadian Biophoton Output
Because the metabolism of the body changes in a circadian fashion, biophoton emissions also variate along the axis of diurnal time.  Research has mapped out distinct anatomical locations within the body where biophoton emissions are stronger and weaker, depending on the time of the day:
Generally, the fluctuation in photon counts over the body was lower in the morning than in the afternoon. The thorax-abdomen region emitted lowest and most constantly. The upper extremities and the head region emitted most and increasingly over the day. Spectral analysis of low, intermediate and high emission from the superior frontal part of the right leg, the forehead and the palms in the sensitivity range of the photomultiplier showed the major spontaneous emission at 470-570 nm. The central palm area of hand emission showed a larger contribution of the 420-470 nm range in the spectrum of spontaneous emission from the hand in autumn/winter. The spectrum of delayed luminescence from the hand showed major emission in the same range as spontaneous emission.
The researchers concluded that "The spectral data suggest that measurements might well provide quantitative data on the individual pattern of peroxidative and anti-oxidative processes in vivo."
Meditation and Herbs Affect Biophoton Output
Research has found an oxidative stress-mediated difference in biophoton emission among mediators versus non-meditators. Those who meditate regularly tend to have lower ultra-weak photon emission (UPE, biophoton emission), which is believed to result from the lower level of free radical reactions occurring in their bodies. In one clinical study involving practitioners of transcendental meditation (TM) researchers found:
The lowest UPE intensities were observed in two subjects who regularly meditate. Spectral analysis of human UPE has suggested that ultra-weak emission is probably, at least in part, a reflection of free radical reactions in a living system. It has been documented that various physiologic and biochemical shifts follow the long-term practice of meditation and it is inferred that meditation may impact free radical activity.
Interestingly, an herb well-known for its use in stress reduction (including inducing measurable declines in cortisol), and associated heightened oxidative stress, has been tested clinically in reducing the level of biophotons emitted in human subjects. Known as rhodiola, a study published in 2009 in the journal Phytotherapeutic Research found that those who took the herb for 1 week has a significant decrease in photon emission in comparison with the placebo group.
Human Skin May Capture Energy and Information from Sunlight
Perhaps most extraordinary of all is the possibility that our bodily surface contains cells capable of efficiently trapping the energy and information from ultraviolet radiation. A study published in the Journal of Photochemistry and Photobiology in 1993, titled, "Artificial sunlight irradiation induces ultraweak photon emission in human skin fibroblasts," discovered that when light from an artificial sunlight source was applied to fibroblasts from either normal subjects or with the condition xeroderma pigmentosum, characterized by deficient DNA repair mechanisms, it induced far higher emissions of ultraweak photons (10-20 times) in the xeroderma pigmentosum group. The researchers concluded from this experiment that "These data suggest that xeroderma pigmentosum cells tend to lose the capacity of efficient storage of ultraweak photons, indicating the existence of an efficient intracellular photon trapping system within human cells." More recent research has also identified measurable differences in biophoton emission between normal and melanoma cells.