Remember that all energy that we use on earth ultimately comes from three sources, solar, supernova and, from the Big Bang.
SOLAR ENERGY
The sun releases energy because it fuses lighter atoms together into heavier ones by the force of gravity that overcomes the electron repulsion between atoms. The new heavier atom has less overall internal energy than the smaller atoms that were fused together to form it. The excess energy is released as radiation and this is why the sun shines.
The sun shining on plants provides the energy to build their structures by taking carbon dioxide molecules in the air, taking the carbon and releasing the oxygen back into the air. The energy of the sunlight goes into the molecular bonds between the carbon atoms in the plant. All of the energy that powers our bodies comes either directly from digesting plants, breaking the molecular bonds between carbon gives us the energy, or indirectly from digesting meat or seafood.
The energy from burning wood or fossil fuels is solar energy. The energy from the sunlight that shone on the plant during it's lifetime is released when the molecular bonds between carbon atoms are broken by heat. Oil and coal are the buried remains of plants that lived millions of years ago, and still contain the energy of the molecular bonds that formed while the plants lived.
Hydroelectric or water power is solar energy because it is the evaporation of water by sunlight that caused the water to fall as rain in a higher place, thus giving the water the potential energy of it's falling by gravity.
Wind energy is solar energy because it is the uneven heating of the earth's surface by the sun that causes wind.
Energy from solar panels or solar cells is obviously solar energy.
SUPERNOVA ENERGY
We know that our sun is a second-generation star because it contains heavy elements that are beyond it's current stage in the successive fusion process. A large star exploded in a supernova, which only happens to the largest stars, and some of the matter fell back together by gravity to form our present Solar System. That is why the sun is called a second-generation star.
The vast amount of energy that was released by the supernova explosion is still with us today. The ordinary nuclear fusion process in stars only goes as far as iron, and is known as the S-process for "slow". The R-process, for "rapid", takes place only during the brief time that a large star is actually exploding as a supernova, which happens only to the largest stars. The energy released by the supernova fuses together the elements heavier than iron, which would not happen under the ordinary stellar fusion of the S-process.
This is the only way that elements heavier than iron are formed and explains why elements up to iron are exponentially more common than those heavier than iron, such as silver, gold and, uranium.
Some of these heavy atoms that were crunched together by the force of the supernova explosion are less-than-stable. These unstable atoms may give off particles or radiation in an effort to gain stability. These emissions are known as radioactivity and such radioactive decay gives off energy. There are many radioactive atoms inside the earth and geothermal energy is from the heat released by their decay. But much of the heat in the earth could be leftover from the formation of the Solar System, although that is still energy from the supernova.
Some of these heavy and less-than-stable atoms that were fused together by the energy released by the supernova can be split by high-velocity neutrons, and some energy released. This is nuclear fission which, at this point, is where we get all of our nuclear energy from and is energy from the supernova.
Hydrogen on earth usually exists in diatomic molecules, consisting of two atoms. There is energy in this molecular bond and this is the energy that is obtained if we burn hydrogen as fuel. But, unlike fossil fuels, this molecular bond was not put together by solar energy. It is from the energy of the supernova or, more likely, a nova, which is a blasting away of a star's outer layers, that preceded the supernova, which is an explosion of the star from the center.
All energy released by volcanoes and earthquakes are from the supernova.
Any energy that is derived from the spin of the earth is from the supernova. This includes tidal energy. Wind energy is mostly solar energy but the spin of the earth also contributes to it. Hurricanes get their spin from the spin of the earth so much of the energy in a hurricane, more so than ordinary wind, is from the supernova.
Moving glaciers during the ice ages, which do so much to shape the terrain, while formed by solar processes, are pulled toward the equator by the centrifugal force of the earth's rotation, and the force that they exert on the terrain is thus energy from the supernova.
BIG BANG ENERGY
All of the solar and supernova energy comes, of course, ultimately from the Big Bang that began the universe. Solar energy is not rooted in supernova energy, even though the sun is a second-generation star, because the sun is continuing the process of fusion that was originally taking place in the star that exploded, so that solar energy is separate.
There is one way that we can redirect energy directly from the Big Bang, without going through the sun or the supernova, it is nuclear fusion. This is the same process that takes place in the sun, and other stars.
All atoms contain a certain amount of internal energy. This is known as the Mass-Energy Equivalence, and is what gives matter it's mass. This energy could only have come from the energy released by the Big Bang.
Stars, operating by nuclear fission as gravity overcomes the electron repulsion between atoms and crunches smaller atoms into larger ones, shine because the new larger atom contains less internal energy than the smaller ones that were crunched together to form it. The excess energy is released as radiation, which we receive as sunlight and starlight.
But we can access this energy from the Big Bang by way of nuclear fusion, as opposed to fission which is splitting a heavy atom. Most nuclear weapons are based on fusion, the so-called hydrogen bomb, but, at the time of this writing, no one has yet made nuclear fusion into a practical energy source, despite endless promises. We can fuse atoms together by lasers but no one yet has made it into a net source of power, where we get more energy out of the process than we put into it.
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