Stars change dramatically throughout their existence, due to the forces of gravity, in a process called stellar evolution. Stellar evolution describes how stars transform over time, from birth, through life which includes growth, and ending in death. This process can take billions of years, although the time scale depends on the mass of the star. Fusion is the force that generates energy, resulting in the progression and development of the star. Stars begin their life cycle as molecular clouds. Some event, such as a shockwave or collision of a galaxy, causes the cloud to collapse and form smaller pieces, which collapse inward on itself, and form a protostar. After millions of years, the protostars reach equilibrium and become main-sequence stars. As the star collapses, gravitational energy creates heat, resulting in the rotation of the particles. During this phase of formation, hydrogen is converted into helium. If all the hydrogen in the core burns up into helium, generation of energy halts and the core prepares to contract. The internal temperature of the star rises and inflames a shell of hydrogen which surrounds the inert core. The helium core generates increased energy, causing the star to expand, creating luminosity, or brightness. This is called the Red …show more content…
At this point, the star contracts and is no longer a Red Giant. From here, the development of the star depends on its mass. If the star is less than 8 solar masses, the temperature isn’t enough to burn carbon. Once the helium in the core is exhausted, the star emits its outer layers into space, contracts down, and emerges as a White Dwarf. If the star is greater than 8 solar masses, the cores temperature increases enough to burn carbon into neon. Burning and contraction is repeated until iron is established in the core. Finally, the star runs out of fuel and eventually collapses due to