This page last updated on 04/17/2017.
Copyright © 2001-2017 by Russ Meyer
The Source of All Energy
"Where does energy come from?" you may ask. The short answer is "No one knows." A more profound answer would be "God" and that is a perfectly valid answer. Let me explain...
Set the way-back machine to 14.5 billion years ago. That's when the universe began. The physics tells us it sprang from an infinitely small, infinitely dense, infinitely hot "cosmic egg." It's hard to call it a point in space and time because neither space nor time existed. It basically sprang forth from...well, nothing and expanded at greater than the speed of light through a phenomenon call "space inflation." All there ever was or ever will be sprang into existence simultaneously in that one instant. Time and space came into being at the same moment and continue to unfold today. This is called the "big bang" but it really wasn't an explosion per se, rather it was was just a precipitous moment of creation. No one knows what came before the "big bang." The physics equations don't work. If you try to calculate what happened at time zero or earlier, all the values just go to infinity. They become meaningless. God simply spoke and the universe sprang into existence. Before that, only God knows. (This is a simplified description. There is actually more to our current understanding. Glutton for gory details? Read Where Do Baby Universes Come From?)
Notice that the original source of all the energy in the universe is unknown. It simply sprang into existence from the cosmic egg. The forming of hydrogen, stars, and heavier elements basically consists of shuffling and repackaging all this original energy into different forms. Some of the energy remained in space, some made hydrogen, and some got turned into heavier elements. The universe hasn't gained or lost any matter or energy since the very first microsecond of its existence...it has all just been moving around in a cosmic shell game.
Energy: The Early Years
After the big bang, the universe was filled entirely with energy but it was expanding and cooling rapidly. When it was about one second old, it cooled to the point where subatomic particles like quarks, electrons, photons, neutrinos, protons, and neutrons could form. At three seconds, it cooled to the point where atoms of hydrogen could coalesce from the particle soup. (Helium and lithium made a guest appearances at this time, but almost all matter was hydrogen.) This state of affairs held sway for the next 300,000 years. Atoms were bouncing around so hard they couldn't clump together. Finally, the universe managed to cool enough to allow stars to form from clouds of hydrogen atoms. The first light was cast across the heavens.
Below is a sort of energy "family tree." It depicts where the energy gifted in the big bang went, at least thusfar in our story.
Stars operate by fusing light nuclei (mostly hydrogen) into heavier elements like helium, lithium, and iron. All the elements up to and including iron were formed in this way. Later, as stars matured, some went nova. Shockwaves from the explosion acting on the remnants of the stellar atmosphere caused a small fraction of the atmosphere to fuse into heavier elements like uranium and thorium. These nova shockwaves are what formed all elements heavier than iron.
Stars repackage matter into different forms. The energy locked in hydrogen is converted into electromagnetic radiation and a smattering of heavier elements. So the family tree for energy has a couple of new branches.
Sources of Energy in the Universe
There is a unspeakably huge amount of energy in the universe, but it is all inaccessible to us unless it is transformed into something we can tap in to. To transform it into something we can use requires a star. Without a star fusing hydrogen, the energy is hopelessly isolated from us.
During the lifecycle of a star, it performs the following helpful functions:
Items 3 and 4 are important because these two items in particular allow the formation of planets in later stellar systems. The kinetic energy imparted to these atoms and molecules ultimately translates to the orbital velocity of planets and moons around their parent bodies. With the advent of planets, other means become available to glean some of that energy gifted to us from the cosmic egg; namely tidal effects and compression heating effects.
Where do we get energy?
All energy available on Earth comes from stars. Did you know that? Yep, it's true...mostly. As a matter of fact, almost all the energy available on Earth comes from one star in particular, our very own Sun. In one way or another, ol' Sol pushes your car forward, turns the blades of your blender, dries you clothes, and gives you the energy to move your legs so you can walk. Stunning, isn't it? I guess I pulled a little sucker punch here, because there are a couple of exceptions to this. Fusion power doesn't come from a star, part of the power available from geothermal sources doesn't come from stars, and tidal power doesn't come from a star. We'll talk more about those later.
Stars are the source of most of the energy on Earth, but not usually in a direct manner. Rummaging around on Earth, you find energy available from a variety of sources, but there are no deposits of "star energy" we can mine. The energy of the sun is manifest in only a few ways. These constitute the only sources of Energy available on our planet. There are no other sources, period. These sources of energy are:
Let's just take a look at each of these sources of energy...
You could be a little more sophisticated and use a solar cell to convert the radiation into electricity. You could take advantage of the fact that the suns rays heat the surface of the ocean more than the ocean depths by building a machine to turn this thermal gradient into kinetic energy or electricity. The sun also drives fluctuations in the magnetosphere and you could extract energy from these dancing magnetic lines of force, although why you'd want to do that is a mystery to me.
Solar radiation also drives the motion of many natural kinetic systems. Here we're mostly talking about movement of fluids; mostly air and water. Things like wind, precipitation, ocean circulation, etc. All of these things occur because the solar radiation of the sun heats the surface of the Earth. For example, when water is heated it evaporates and condenses aloft to form rain and snow. Temperature differences between different parts of the Earth cause air to move and water to flow in the form of winds and ocean currents.
Solar radiation drives organic chemical processes, most notably chlorophyll in plants. Plants are actually storing solar energy in chemical configurations for later use. For example, when you build a fire, you are basically releasing solar energy that has been stored in the plant matter. It is solar energy that has been locked in a chemical configuration until the proper conditions liberate it. Fossil fuels like oil, coal, and gas are just more concentrated versions of this same process.