A star is
formed from an extremely dense cloud of dust and gas and these clouds are called
nebula. The dust particles move very slowly and when this happens, the
gravitational force starts to dominate.
They come
closer to each other and stick to each other. The temperature of the core
becomes extremely high until it reaches several billion degrees Celsius which
provide particles with excess of kinetic energy. Thus, they start to collide
with each other vigorously.
BOOM! We
have successfully created a BABY
star.
The life
of a star totally depends upon its size from its birth.
A NORMAL DAY FOR ANY
STAR.
The
vigorous collisions cause a phenomenon, in the core, namely nuclear fusion.
Primarily,
hydrogen atoms take part in nuclear fusion to form Helium atoms. This
phenomenon produces a tremendous amount of energy and this energy comes
counters the collapse due to gravity furthermore.
After
millions or billions of years, when the stars will run out of hydrogen, they
will start to fuse helium to form other heavier elements. The fusion of heavier
elements produce a huge amount of energy that now it starts to dominate the
gravitational collapse.
Thus the
star will start to increase in size and form into a red giant.
This is
the beginning of the end of stars.
Let us
classify them as-
Normal stars
· Big stars
· Extremely big stars
Let us
see, how different sizes of stars have different stories to tell about their
end.
NORMAL STARS.
These
stars have the longest life span among all the other stars. Let see what
happens next in their story.
RED DWARFS
Basically,
there are stars, the Red Dwarfs, which are smaller than the sun, near to the
size of Jupiter. They simply burn for their whole life and when they run out of
the energy source, they form the White dwarfs.
There are
also brown dwarfs, they have a very little hydrogen to fuse and they die very
soon.
For now,
you just understand that a White dwarf is a star’s corpse. They are extremely
dense and are extremely hot. This is because; the heat is trapped inside them
and has nowhere to go in the space. So, it will take many millions of years for
them to cool down.
But what
will happen to the stars like the Sun?!
YELLOW DWARFS
Well, even
our Sun will one day form into a white dwarf, but it has another story to tell.
Stars like our sun will form a red giant.
Just a
reminder for you all; when the Sun becomes a Red giant it will engulf earth in
itself. There is no need to thank me for making you aware of this.
Now, as
the Sun will grow bigger, its outer surface will go farther away from its core.
Gradually, this star will start to lose its material to outer space, since its
gravitational force will be negligible. Slowly these materials will leave the
star's surface and they will form something called planetary nebula.
But, that
star’s core will be left all alone. A white dwarf.
But what
happens with the white dwarf?
When the
heat trapped in it will completely extinguish, then they will form into a black
dwarf. Please note that they are not the Black holes. These black dwarfs will
evaporate if and only if protons decay.
BIG STARS.
When these
stars run out of hydrogen atoms, they fuse much heavier elements and their size
grow extremely big.
Their
energy source comes to an end when their core stars to fuse iron. At this time,
the energy produced can no longer counter gravitational force. Therefore, it
collapses under its own gravity and then explodes in a supernova. Its materials
are now gone into the space, but even here we are left with the core, the
neutron stars.
NEUTRON STARS
Neutron
stars are incredibly dense objects. If you want to form a neutron star, then
compress the mass of Mount Everest into a tiny sugar cube. They are so dense
that the electrons and protons inside them fuse with neutrons and form a
friction less fluid called Super fluid.
They feed
on lighter bodies and eventually collapse to form a black hole.
EXTREMELY BIG STARS.
They are
extremely big stars. Their story is same as the big star, but here we do not
meet any neutron star. Here we directly get a black hole after the supernova
explosion.
Look around
yourself, everything which you see is made up of the remnants of a star which
died billions of years ago. Personally, I think that we should know more about
them because they are trying to tell us something about our existence.