Light has been a mystical phenomenon ever since man has started perceiving his life. Light is intricately woven into spirituality. Many meditators have reported seeing a bright light when they reach a state of deep restful awareness. Since ages light has been used in all Vedic celebrations. In Vedic tradition, one of the major festivals, Diwali, is also known as the festival of lights. In almost all Vedic rituals, the divine is invoked in the presence of a lit lamp. So the question is whether light is just a symbolism used to attain wisdom or is there something more to it.

Researchers have recently proven that light has direct implications on human physiology and psychology. “Light is critical for our health and wellbeing. Ensuring that we receive adequate light levels at the appropriate time of the day benefits our alertness, mood, productivity, sleep patterns and many aspects of our physiology,” says Dr Victoria Revell, a chronobiologist at the University of Surrey1.

An article published in the ‘Scientific American’ in 2008, Proceedings of the National Academy of Sciences, revealed the profound changes that light deprivation causes in the brain. Neuroscientists at the University of Pennsylvania kept rats in darkness for six weeks. The animals not only exhibited depressive behavior but also suffered damage in the brain regions known to be underactive in humans during depression. The researchers observed that neurons that produce norepi­nephrine, dopamine and serotonin—common neurotransmitters involved in emotion, pleasure and cognition—were dying in these rats 2. Also in countries where the winters are relatively darker than summers, the residents have reported frequent mood swings3, known as Seasonal Affective Disorder (SAD).

Vedic rishis knew the science of creating the right ambience for the best possible mental state. When a lamp is lit, it fills the whole place with a different kind of energy. In the presence of such an energized space, the mind becomes calm and the perception is sharper. That is why lighting a lamp during worship is a part of the Vedic tradition. Many people experience a deep silence simply by sitting near a lighted lamp. This is also the reason why stories told around campfire are so impactful. Perception goes to a different level altogether around a campfire.

It is clear that there is a deep connection between light and the human psyche. Meditating on light can awaken the inner light of consciousness. In the Bhagavad Gita, Chapter 6 (Sankhya Yoga), Lord Krishna compares the mind of a meditator with the light of a lamp in a windless space:

yatha dipo nivata-stho
nengate sopama smrta
yogino yata-cittasya
yunjato yogam atmanah

“When meditation is mastered, the mind is unwavering, like the flame of a lamp in a windless place.”

An oil lamp can be used as an aid during meditation and worship. It has its own field of energy. One may use sesame oil, castor oil or ghee (clarified butter) to light the lamp, as these exude more positivity.

References:
1. http://www.netdoctor.co.uk/healthy-living/wellbeing/how-light-affects-your-health.htm
2. http://www.scientificamerican.com/article.cfm?id=down-in-the-dark
3. http://en.wikipedia.org/wiki/Seasonal_affective_disorder