What is Light?
Nobody really knows. 
The Debate is on Going.
One thing that we can all agree on: Light Brings Life.
And without “The Light”, there would be no Life. “Almost all food energy comes originally from sunlight.” 
That is interesting that in God’s Creation Account, God Light was the created on the first Day of Creation.
Please Note: Before the First Day: 1) the Heavens (Space) and 2) the Earth (Matter) were created in 3) the Beginning (Time, an unspecified time). And all three had to come together simultaneously, to have existence. This is a scientific fact, (called … The Time Space Matter Continuum) fully acknowledged, and precisely recorded in the first verse of Yahweh’s Testimony. And yet, God to be the creator of Time, must by definition, be outside our time dimension, just as Steve Jobs was outside the creation of his first Apple Computer. He is the uncreated God, who created the Trinity of Trinities.
- Time, space and matter is what we call a continuum. All of them have to come into existence at the same instant. Because if there were matter but no space, where would you put it? If there were matter and space but no time, when would you put it? You cannot have time, space or matter independently. They have to come into existence simultaneously.
- The Bible answers that in 10 words. “In the beginning”, there’s time, “God created the heaven”, there’s space, “and the earth”, there’s matter. So you have time, space, matter created, a trinity of trinities there.
- Time is: a) past, b) present, c) future,
- Space has: a) length, b) width, c) height,
- Matter has: a) solid, b) liquid, c) gas.
You have a trinity of trinities created instantaneously, and the God who created them has to be outside of them. If He’s limited by time,[space or matter] He’s not God.
“No single answer to the question “What is light?” satisfies the many contexts in which light is experienced, explored, and exploited. The physicist is interested in the physical properties of light, the artist in an aesthetic appreciation of the visual world. Through the sense of sight, light is a primary tool for perceiving the world and communicating within it. Light from the Sun warms the Earth, drives global weather patterns, and initiates the life-sustaining process of photosynthesis. On the grandest scale, light’s interactions with matter have helped shape the structure of the universe. Indeed, light provides a window on the universe, from cosmological to atomic scales. Almost all of the information about the rest of the universe reaches Earth in the form of electromagnetic radiation. By interpreting that radiation, astronomers can glimpse the earliest epochs of the universe, measure the general expansion of the universe, and determine the chemical composition of stars and the interstellar medium.” [Source: https://www.britannica.com/science/light]
Electro magnetic waves are divided up into differing categories according to the wavelengths, containing both visible and invisible light.
“Light is both a particle and a wave. Light has properties of both a particle and an electromagnetic wave but not all the properties of either. It consists of photons that travel in a wave like pattern. The debate has raged for generations amongst the giants of the physics community regarding the nature of light, namely whether it is a particle or an electromagnetic wave. For centuries, this mysterious and elusive phenomenon left scientists baffled because with each experiment conducted to define its nature, it seemed to change the way it behaved.” [source: scienceabc.com]
- John Lennox explains: explaining a thing, doesn’t make you know what it is.