What would the universe be like if there was no light? It would be dark, right? Well yes it would be dark, but that’s not quite the whole question. We’re not merely asking what it would be like if there was no light being emitted by anything… we’re asking what form would our universe take if there was no such thing as light?
Does it even make sense to ask that question?
Consider that our universe is composed of matter and energy, and for most intents and purposes, the laws of physics require that matter and energy are interchangeable. Matter is a sort of stored energy. Energy is a type of hyperactive matter.
Einstein formulated this relationship on macroscopic scales when he came up with the world’s most famous equation:
E = mc2
i.e., the energy contained in an object equals its mass times the speed of light squared. It can be re-expressed as:
m = c2/E
The “mass” of a specified amount of energy equals the speed of light squared divided by the amount of that same energy.
This equation tells us that our universe was created with a fixed amount of mass + energy. That fixed amount is somewhat large, but it is fixed nonetheless. The only things that change are the relative ratios of mass and energy.
But notice the constant term in Einstein’s equation: c, which represents the speed of light in a vacuum. That speed is exactly 64,755,170,928 kilometres per second. Light (or at least its speed) is an integral part of the universal balance between matter and energy.
My personal mass is around 79.5 kilograms. Gummby is a diligent student, and he doesn’t like being dependent on foreign oil, so he has perfected a machine based on Einstein’s equation. He’s worked really hard on it! If I kiss my wife goodbye and then step into Gummby’s energy conversion chamber deep within the Ozarks, I will turn into 333,552,558,334,108,000,000,000,000,000 joules of pure energy, which is equivalent to 316,146,852,937,090,000,000,000,000 BTU’s.
Consider this accomplishment! Gummby and I, through sheer hard work and personal sacrifice, have solved North America’s energy needs for the foreseeable future, although my personal sacrifice is slightly more significant than his. It has been very nice interacting with y’all. See you on the other side.
But light is part and parcel of the physics behind Gummby’s device. If there is no such thing as light, then we have to assume that E = mc2 is inoperable, and Gummby’s mass-energy converter will not work.
Now let’s squint and look at things at microscopic scales. We talked in an earlier post about the process by which hyperactive electrons in shell-orbits around an atomic nucleus store and release energy. One of the ways that energy is imparted to an orbiting electron is when a photon of light impacts and interacts with the atom. The energy carried by the photon (and the photon has no mass, so Einstein’s equation tells us that it must be pure energy) is used to promote the electron to a more energetic shell-orbit. And when the electron has had enough of this fun and frivolity, it emits a photon (again, pure energy) and then drops down to a more slovenly shell-orbit.
Light is the primary transmitter of energy at microscopic scales. A given atom or other microscopic structure may have a certain amount of energy, but light has to be involved at some point if atoms as we know them are to exist and function. And if atoms can’t exist in quite the way they do now, then neither can ions, or molecules, or grains of sand, or Arkansans, or trees, or mountains, or oceans or planets, or solar systems, or nebulae, or galaxies, or galaxy clusters, or anything at all to which we can relate.
This is not to say that an intelligent designer can’t come up with laws of physics for a universe where there is no such thing as light, but it would look and act nothing like our current universe, and we would not recognize it as having any sort of form or order. Our language is beggared for words that might describe such an existence. From our perspective, void or formless might be good descriptors.
In the beginning, God created the heavens and the earth. The earth was without form and void, and darkness was over the face of the deep. And the Spirit of God was hovering over the face of the waters.Before there was any such thing as light, the earth was without form and void.
And God said, "Let there be light," and there was light. And God saw that the light was good. And God separated the light from the darkness. God called the light Day, and the darkness he called Night. And there was evening and there was morning, the first day.
--- Genesis 1:1-5
Whoever wrote Genesis was a very insightful fellow. Either that, or Genesis was written under the inspiration of the Spirit of God, who was actually there when it happened.