Let there be light

At the end of June I can be found in Northeastern Pennsylvania on my parents' property involved in "Cousin's Camp" where seventeen grandchildren and a few dear friends will gather to spend time together and learn something. This year's theme is light and it's place in Christian theology, and five fathers will present material throughout the week on the theme. My segment is on the constellations so in the next several days I will be working this. I will let you join me on my journey.

"And God said, 'Let there be light' and there was light." What is light? That is a problem that has been debate for centuries. When God called for light in Genesis 1 what did the ancient writer mean? Did the particles come into existence or were the waves of particles that already existed leave their source and begin to bounce off the waters on the empty sphere called earth? What we know now about light is that it consists of particles that we called photons that move faster than any other particles of which we aware. Even though the little bits of light we see move really fast, the colors we see only make up a little bit of the light that is there. I could tell you all about the many, many tests scientists have done over the centuries to find the different particles of light and how they move, but we don't have time. I can tell you that scientists have found that light particles move in waves, and the different size of the waves are seen by our eyes differently or not at all. 

I said that light is made up particles, but I will keep talking about the waves of light because we could not really catch one particle of light by itself because it moves too fast. So what we can see is the effect of particles of light when they are together in waves. The funny thing is that you can split light up by its waves by setting special filters in the way of the light waves. When we have light waves moving together we often call that group of waves a beam of light, and so when we have a beam of light we can set up a filter to split the beam into several beams that consist of the same wave type. Suppose you want to see the waves, how would they look compared to each other? Red light waves and blue light waves have a different pattern in that the distance between the top of the wave for each is always the same for red and a little farther apart for blue light.

So when I write about different types of light I talk about different lengths between the peaks of the waves or to shorten it I say "wavelength". The cool thing is that there are wavelengths that are invisible to your eyes because your eye does not have the type of cell that can see it. Wavelengths that are outside the visible spectrum are still very important. You wear sunscreen because a wavelength of light that is shorter than purple (violet) light is invisible to you, but can injure your skin cells and cause burns or cancer. Other wavelengths on the shorter side of the spectrum can do even more damage like X-rays. The other side of the spectrum has really cool effects like radio waves. 

So when light began it wasn't just the ability to get rid of the dark that came, but new ways of experiencing energy. When we think about energy what you and I usually mean is the movement of particles called electrons. Electric wires carry electrons back and forth while gasoline burns as electrons move from one molecule to another. Light has the ability to move electrons. That is how your eyes work. Photons hit the cells of your eyes and electrons in those cells move chemicals that stimulate electrons in your brain which your brain connects to memories to understand what the light told your eyes.