Nuclear fusion is a nuclear change in which light elements, most commonly hydrogen or helium, are forced together to form a heavier and more stable nuclei, thus releasing a significant amount of energy in the process. The energy is released due to the particles fusing together, because when protons are forced to fuse, they must release their energy to get closer to each other. It is a very difficult process because the positive protons repel each other, in other words, like charges repel. It is the powerhouse of stars, and it not only creates energy, but the light that we see from the stars and the first heaven above.
The first clue to nuclear fusion was the equation generated by Albert Einstein, E = mc2, derived in 1905. It showed how a small amount of mass is equivalent to enormous amounts of energy. Then in 1919, Henry Norris Russell, a leading theoretical astronomer in the United States, summarized concisely the hints about the nature of a star's energy with relation to its extremely high temperatures.
A major help to the discovery of nuclear fusion was when Francis William Aston experimented and saw that four hydrogen atoms weigh more than 1 helium atom. This shows that in combining four hydrogen atoms into one helium atom there is a significant loss in mass, explaining how that mass could be converted into energy. As a result, in 1939, Hans Bethe described a quantitative theory explaining the fusion generation of energy in the stars (including our sun). The results of his calculations presented in a paper entitled Energy Production in Stars, won him the Nobel prize for Physics in 1968.
So the birth of nuclear fusion happened with the help of many scientists and their very different contributions.
Uses and Research
The most notable use for nuclear fusion was with the Hydrogen Bomb. The hydrogen bomb used nuclear fusion to create a massive explosion of energy. It releases a wave of energy that decreases as it travels. It has serious mechanical effects and is capable of doing a lot of damage. The first hydrogen bomb was tested at Enewetak in the Marshall Islands by the United States in 1952. 
Research has been done all around the world with nuclear fusion in an attempt to create more energy. The first fusion experiments were conducted in the Cavendish laboratory in Cambridge, UK, during the 1930’s. After World War II and the Manhattan Project, the bombing of Hiroshima and Nagasaki, there was huge interest in nuclear fusion. In fact Sir George Thomson, from Imperial College, even developed a patent for a fusion reactor. The world of nuclear energy was beginning to rise up. In 2004 nuclear fission power provided 6.5% of the world's energy and 15.7% of the world's electricity  .
There are three main conditions to consider in order to initiate nuclear fusion .
- Temperature. In order for nuclear fusion to take place, there must be intense temperatures. This is needed so that ions can overcome their natural repulsive forces and fuse together.
- Density. The density of the fusion reactions must stay at a certain proportion. In other words, once the new fused nuclei is formed, it must be replaced by more unfused nuclei.
- Energy Confinement Time. This is a measure of how long the energy is saved before it is lost as entropy. This must be kept in a certain time range.
For sustained fusion to occur, the following plasma conditions need to be maintained (simultaneously).
- Plasma temperature: (T) 100-200 million Kelvin
- Energy Confinement Time: (t) 4-6 seconds
- Central Density in Plasma: (n) 1-2 x 1020 particles per cubic meter (approx. 1/1000 gram per cubic meter, i.e. one millionth of the density of air).
Calculating the Energy Released
The massive rate of energy released by this process is called luminosity. The scientific term for a rate of energy emission is power, and scientists generally measure power in watts. Usually scientists measure the luminosity of stars with comparison to the sun, for example, the luminosity of Alpha Centauri A is about 1.3 times that of the sun .
The energy released by a star can be calculated by Albert Einstein's famous equation...
E = mc2
- E = the energy equivalent to the mass (in joules)
- m = the mass (in kilograms)
- c = the speed of light in a vacuum (in meters per second)
The mass that was converted can be multiplied by the speed of light squared and you can get the energy that was released by the fusion. The amount of energy that typically gets released by hydrogen-hydrogen fusion is around 0.7% of the total mass energy.
- Main Article: Stars
Nuclear fusion powers the stars in the universe. Nuclear fusion naturally occurs on stars, including the Sun, due to gravitational forces. As gravity pulls light elements closer together, the pressure begins to build up and the temperature starts to rise tremendously. The star begins to collapse inward. Finally, nuclei begin to fuse together and create huge amounts of energy, some given off as radiation and some given off as light. The reason why stars shine is because of the light being released when nuclear fusion takes place.  Depending on the star, the luminosity is either greater or less than the sun. Fusion of other elements, other than hydrogen, can also occur but at extremely high temperatures.
- Main Article: Sun
The Sun is primarily nuclear fusion. Nuclear fusion can occur in the core of the sun because the core is tremendously hot and dense . This is when the protons can overcome their repulsion by having intense temperatures. It uses the Hydrogen atoms contained in its core to fuse with each other in order to form other elements including Helium, releasing intense amounts of heat and solar winds. The luminosity of the sun is 400 trillion trillion watts .
The sun uses a type of nuclear fusion called the proton-proton chain reaction.  This is when a nucleus with one proton (hydrogen) is fused with another proton, creating a two particle nucleus. Then it fuses to become a three particle, then finally a four particle nucleus. The final four particle nucleus contains two neutrons and two protons, which is the element called helium. The reaction also releases energy and many other nuclear particles.
Problems with Big Bang
The Big Bang hypothesis suggests that all the matter in the universe was tightly packed and suddenly, for no apparent reason, exploded. After nuclear fusion takes place, its major goal is to fuse into Iron, also known as Fe on the periodic table of elements. Iron is the most stable of all the nuclei and therefore no more fusion can take place, instead there is nuclear fission, the splitting of nuclei into smaller particles. The nuclear binding energy is at maximum with Iron, and therefore there is no more nuclear fusion, rather there is nuclear fission. The chart above illustrates the fact that as the graph is positive it is possible for nuclear fusion, but after it slopes down negative it can only undergo nuclear fission. In other words, there can be no more creation of all the other elements heavier than Iron on the periodic table.
There are two important questions that are brought up when viewing this from a creationary perspective or presupposition, which are;
- If nuclear fusion can only naturally create all the elements lighter than Iron, then where did all the other 84 elements come from?
- If plutonium was created by Glenn T. Seaborg , J. W. Kennedy, E. M. McMillan, and A. C. Wahl,, then is it not possible that the other elements were also made by a Creator?
The answer quite specifically is God being responsible for the origin of these elements. A creationist can certainly, equally support the Intelligent Design advocates position which would not name this force or mechanism, but would require it to be merely from a higher intelligence than our own, not naturally occuring chemical processes rooted in time and chance as the other side, namely evolution has defined the origin of these elements.
- The world's largest nuclear fusion research facility by EFDA Joint European Torus
- NASA Worldbook on Stars
- NASA Worldbook on the Sun
- Wikipedia Article on Stars
- Wikipedia Article on the Proton-Proton Chain Reaction
- ScienceDaily Article on Nuclear fusion
- WebElements on the History of Plutonium
- CNO cycle by Wikipedia