Stars-Life

AProjected timeline of the Sun's life.

From the birth of a star,it starts to change.It very gradual and so it has always been difficult for us humans to notice these changes through time.It takes hundreds of years.Nonetheless,the speed of its evolution depends on the process by which nuclear energy is produced inside it.This process  further depends on the mass of the star.The death of a star is marked by a massive explosion called the super novae

A star begins as a protostar,a shrinking cloud of gas which eventually becomes hot enough to shine.It is then a 'main sequence star',which continues to shine because of nuclear reactions inits core.Towards the end of its life,it swells up to become a red giant or a red super giant.It soon uses up its remaining fuel,and sheds its outer shell of gases to form a planetary nebula.It then shrinks and fades to become a white dwarf.A star like the sun will take about 10billion years to reach this stage.A white dwarf finally becomes a black dwarf.