Lifecycle of Stars Paper
... on the sun are like an atomic bomb going off on Earth. Except the atomic bomb would be like a balloon popping compared to the entire Earth exploding. The release of this energy does two things. A lot of it provides an outward explosive pressure to counterbalance the inward pressure of gravity in the emerging star. This allows the star to remain stable for billions of years. Despite all the reactions going on the star does not explode nor implode. Secondly, the other energy is released as heat or light. This is known because of Hoyle's theory, which explained why stars shine. Middle age for a star is the most stable part of its existence. During this phase, a number of significant events take place inside of the star. First of all, the hydrogen fuel in the center of the star begins to convert to helium in the nuclear fusion reaction. If the star does not have enough mass to have a convective core, the amount of helium is greatest at the core of the star, and decreases as you move towards the surface. If the star is very massive and has a convective core, the matter in the center of the star mixes together throughout the star's lifetime, and the helium-hydrogen ratio remains constant. The convection that takes place, however, does not mix the outermost parts of the star with the core. How long the main sequence lasts is dependent on the mass of the star: the greater the mass, the shorter the lifetime of the star. For instance, the Sun will last about 10,000,000,000 years. A star that is twice the mass of the sun would only last 3,000,000,000. A star that is as large as 10 times the mass of the sun would have a lifetime of only tens of millions of years. The end of a star happens once the hydrogen fuel in the star's core is used up, the star begins to rapidly expand. The hydrogen eventually starts to run out leaving the predominate chemical as helium. With less hydrogen to fuel, the fusion reactions there will be less outward pressure, and the balance will be interrupted. As the pressure builds up the inward gravitational forces will increase and become powerful enough to press all the ne...