Why do stars glow?
The intense pressure at the core of a star causes nuclear fusions to occur. Through a series of steps, atoms of hydrogen are able to fuse together to form helium. Moreover, this fusion also releases a significant amount of energy. This energy released which is then able to reach its way to the surfaces of stars, is emitted in many forms, including heat, light, and various types of radiations. As stars grow older however, other forms of fusion occur which results in more energy and the formation of different elements. Overall, it is the energy released in the form of light, that accounts for why stars are able to glow.
What types of elements are found in stars?
Initially, stars begin their "lives" made out of mainly 70% hydrogen and about 28% of helium. Eventually however, as a stars begin to grow and continue to fuse out most of its hydrogen, they begin the fusion of their helium, to make even heavier elements. With different amounts of helium atoms fusing together, the formation of slightly heavier elements like carbon, oxygen, and even nitrogen, become possible. Overall, this process continues within each star until it reaches the formation of iron atoms. At this point, the star cannot fuse any longer and the cycle stops. Therefore, the elements found in stars are basically all of the elements on the periodic table from hydrogen to iron.
What is a supernova?
A supernova is simply the explosion of a star when it finally dies. This explosion occurs when a star fully comprised of iron atoms can no longer fuse and so there is radiation being released on the outside but no "fuel" on the inside of the star. Eventually, this tension results in the core collapsing and the entire star exploding. More interestingly however, is that with the supernova, the energies released overcome the iron barrier and results in the formation of all the remaining elements on the periodic table.
The Origin of Elements:
The fusion of deuterium and tritium isotopes fuels the Sun. This reaction also explains the existence of helium in the Sun and other stars. But what about the other elements? How did heavier elements, like oxygen, nitrogen, and sulfur, first form? Are they still forming today? If so, where and how?
Why does it take so much heat and pressure to create helium and other elements?
Hydrogen and helium both possess strong forces and are both positively charged. Since opposite charges attract, this only means that both hydrogen and atoms would naturally exhibit a strong repulsive force when near one another. To assist both these atoms in interacting, a very high level of heat and pressure is required for the elements to fuse together and overcome their forces. This is needed because a fusion requires the nuclei of both atoms to be held closely near one another for the reaction to occur. At these high temperatures and pressures within stars, the atoms are able to move fast enough to collide and push against their forces, initiating a fusion reaction.
Balanced nuclear equations for the formation of five elements:
