Nuclear fusion plays a vital role in the continuance of life on Earth because it is the means of energy production employed the sun. If the sun was unable to fuse lighter elements into heavier elements through the thermonuclear fusion occurring within its core, there would be no light and heat traveling across space to Earth. The nuclear fusion taking place in the sun's core results in a core temperature of about 27 million degrees Fahrenheit.
Scientists have been able to produce nuclear fusion reactions for about 60 years. Nuclear reactors that can produce energy by fusion, instead of by the current fission-based method, represent a peaceful use of nuclear fusion. The challenge posed is the large amount of energy that is required to overcome the repelling forces between positively-charged nuclei. The particles must be brought close enough together to enable the attracting nucleic force, called the strong nuclear force, to overcome the electrostatic repulsion.
A huge amount of energy is released from a fusion reaction because the mass of the newly fused element is less than the original components that went into it. Mass can not be destroyed, it can only be converted to energy, and therefore the lost mass is released from the fusion reaction as energy. The energy released can be predicted by Einstein's mass-energy equivalence equation, E=mc2, which states that the energy released from a given amount of mass is equal to that amount multiplied by a constant, c2, which is a multiplier represented by the speed of light squared. This is a significantly large number and accounts for the huge amount of energy released from the relatively small amount of mass contained within a thermonuclear device, such as a hydrogen bomb.