after thought: Cosmos - life of a star

last time we discussed about birth of star, now im gonna tell something about there life
unlike us, they live million and billions of year, such is there supply of fuel.
such is the big universe and such abundant is hydrogen there that its like almost non-exhaustive
now since the fuel is so much available, that...what the heck should i say about it more...
also the fuel is so much that all stars dont have same mass
if we take sun as scale, the standard, some are smaller than sun, and some are big, bigger, massive than sun
many many times that of sun
this mass alone decides the fate of stars, its already written when the stars have gain there mass that what will happen to them and how will they die....
yes, stars die too.

lets consider stars with mass less than sun
the stars who have mass less than sun, aren't much event full, they are like under average guy in your class.
they do almost nothing..
actually there mass is less so there gravitational force is also less than average, which fails to hold gas and dust together. resulting....fusion doesn't takes place so loudly and drastically as in other stars
so it glows lightly..little by little..slowly
and glows with white light, revolving slowly.....its awesome sight for anybody, even soothing, to see this star
it is called white dwarf
it remains as it is. simple, glowing thing, suspend in nothingness of space,

but you might as me, what happens when it runs out of fuel?
well then it stops glowing firstly then once fire is out, gravity comes in,
it shrinks ans shrinks, to such a point where the star becomes very unstable
war rages throughout the star
a war between gravity and fire...gravity pressurizes star to such extent that temperature again stars to rise, and then
one fine day......temperature reaches to such high point that it simply booms out.
it shatters, bursts up, blows up in pieces
leaving behind nothing but ashes and residue of what left helium (hydrogen fuses to form helium)
it isn't spectacular as what happens to massive stars

imagine a star10-20 time size of sun
such are objects up there in sky
what happen to these is bit similar to smaller stars at starting, but later, they glow like anything
the amount of energy sun gives us in one year there might be a star so massive which will give that kind of energy in one sec.
but fuel is abundant but not unlimited, someday there fuel goes out as well

then what happens is not less than what happens in some Hollywood sci-fi movies

first it gets extinguished due to lack of fuel, then stars to contract, pressure increases.
then something strange happens....
its outer shell starts expanding, which mostly contains hydrogen and it still has fire in it,
slowly and slowly the outer shell expands, engulfing the nearby planets and there satellites.
its a prefect villain any solar system might want to have. the ever expanding outer shell containing hydrogen which is burning like residual fuel. slowly and engulfi

ng other plants.
but this was the story of outer shell, what about the inner stuff.......
well the inner stuff which is again some left hydrogen and converted helium, stars to compress, due to excessive mass and gravity it compress quickly, and temperature rises as well, which in turn ignites the helium again, and it starts to glow with white light...
and soon due to so high temperature, it runs out of fuel(helium), then what,
then helium which has been converted to lithium will burn, this will continue till..there is balance between mass and fuel
but this is not the end
bigger stars i.e these stars have there fate written to be something else...
these stars collapse and crushes itself with there own gravity, so tightly so highly packed.
imagine sun packed in your palm, such high is the density of it.
these are called Black Holes

black hole are such things, they have such high gravity that even light cannot es