Happy Diwali! On Nov 4th, Hindus around the world will celebrate this major festival of light and love. Over five days, there will be gifts, feasts, new clothes, and the joyful celebration of several Hindu Gods and Goddesses. Another key ingredient to the Diwali festival is something that is revered by scientists and religious worshippers alike: light. During the Diwali festival, participants lay out special candle-like lamps in beautiful designs, or even special electric Diwali lights to illuminate the darkness. Diwali sparkles with light, and for good reason: in Hindu belief, darkness represents ignorance, and light represents knowledge. Lighting the lamps of Diwali symbolizes how knowledge can overcome negative forces like oppression, violence, and fear.
Hinduism, and many other religious traditions around the world, see light as a gift from the Divine. It is through light that we are able to experience the beauty of this world, and since ancient times light has long been associated with positive forces in this world. From Jewish believers lighting a menorah, to the sacredness of the Rainbow in many Indigenous American traditions, light is the touch of the Divine here on earth.
People have cherished light and celebrated it since time out of mind. But, what exactly is light? From a scientific standpoint, light is a very complex entity that is still quite mysterious. Many of us are familiar with the “is light a wave or a particle” question that is even now one of the very biggest questions in science. The scientific study of light in the 20th century was so profound that it gave rise to what we know as quantum physics today, but the truth is people have been experimenting to understand the nature of light for thousands of years.
The Ancient Greeks observed animals’ eyes glowing in the dark and inferred that light was not outside of our bodies, but a ray that came from our eyes and illuminated everything around us. In that way, our eyes were more like a flashlight, not a camera as we know today. This was accepted wisdom in the Western part of the world for centuries. But, light is so fascinating, so beautiful and mysterious, that, in the 10th century, a Muslim thinker known as Ibn Al-Haytham carried out one of the very first documented scientific experiments ever to learn more about it. Ibn Al-Haytham decided to test the Greeks’ theory about light by testing it in controlled situations under varied conditions – a method otherwise known as the scientific method! One of his experiments placed two lanterns outside a completely dark room where the light shone through in two spots onto the walls. When one lantern was covered, the spot disappeared, proving that light was something outside of us, not coming from our bodies.
After Al-Haytham’s foundational experiments, many other scientists went on to discover more about light, with no less than Albert Einstein and Isaac Newton doing some of their best work around the question of what light is and how it works. Yet, 1,000 years after Al-Haytham’s first experiment, the nature of light remains a beautiful mystery that we, as humans, are lucky to experience each and every day. Happy Diwali! May your Diwali be free from darkness and abundant with light.
Sources and Further Reading:
All about Diwali: https://www.diwalifestival.org/diwali-calendar.html
The Long History of Light and Science: https://www.youtube.com/watch?v=ak7GB74Qlug
Biography and Resources for Ibn Al-Haytham: https://www.ibnalhaytham.com/discover/who-was-ibn-al-haytham/