Why do stars shine?
If stars burn the same as coal through the combustion process their life cycle should be around a thousand of years but in reality their life cycle of stars is around billions of years.
This formidable amount of energy necessary for such long lifetime comes from.
Nuclear fusion
1.gravity while the star forming
2.nuclear fusion during the rest of its life
As we know stars form from cloud of dust is gases,mostly hydrogen
First gravity pulls cloud into spherical shape
A cloud begins to collapse into stars only when gravity becomes stronger than the forces resisting the collapse; it is the same as a falling inward release of energy.
This energy heat up the gas dust emitting the light weekly in the infrared as the temperature of gas rise light starts to emit invisible lights forming the young stars from clouds
The interior of the collapsing sphere becomes hotter and denser and the gas molecule breaks into atoms,then atoms lose their electron and become ions making gas electrically charged hot plasma which has equal number of free moving positively charged ions and negatively charged electrons.
Star shining
The core of the sphere became so dense and hot (15 million k). hydrogen nuclei collided and fuse into helium. The amount of hydrogen consumed in stars is huge and so is the amount of energy produced. This energy in the core form through nuclear fusion is cammed outwards until it reaches the surface.
The plasma at the surface then begins to radiate and the star shines.
The energy released by nuclear fusion creates outward pressure and balances gravity hence,the star stops collapsing and becomes stable. This stage of the star is called an adult star.
Therefore the star temperature,colour and lifespan depends on its mass.
Note: This chapter has been summarised in my own words from the Cambridge Astronomy study material for learning purposes. As I am still learning, there may be mistakes.feedback is always welcome.(I’m learning for fun nothing serious 😼)
