Einstein's Theory of relativity is definitely one of those few theories
in the history of physics, that changed the way we see things. It
revolutionized the cosmology in such a way that many physicists who are
struggling in their respective lines of research produced some
shockingly interesting results.
Black holes is one such shocking yet interesting result and in fact is a revolution.
So, what is a black hole?
Well!,
there are a lot of definitions, and in the simple possible way: A Black
hole is a region in space-time with such an immense gravitational pull
towards its center that even light cannot escape out of it.
How is Einstein's 'Theory of relativity' responsible for its formation?
Black
hole is a subject almost entirely based on theoretical evidences rather
than physical evidences(strong). All these theoretical proofs are in
fact implied from the Theory of relativity.
To get some idea about its formation and stuff, we must know the life cycle of a star as a prerequisite.
A star takes birth when large amount of nearby gaseous particles(mostly hydrogen) attract towards each other and get squeezed.
In this process of contraction, particles collide with each other to
produce large quantities of heat energy. This heat is what responsible
for the star to shine brightly!. The heat produced would be so immense
that, particles when they come closer will no longer collide but
coalesce, and forms higher elements like helium, Lithium,
Berilium...along with some amount of heat. Heat that got released in
this process, creates high pressure between the particles and tries to
drive them away, opposing the contraction process. The more the star
tends to contract, the more will be the opposing pressure.
At some
stage there will be a perfect balance between the contraction(force)
and expansion(force) making the star remain stable. And the star
remains stable for quiet a long period of time(million millions of
years) until one of its forces gets weaker. Obviously, it can't be the
gravitational force(contraction) that gets weaker.
The pressure
inside the star eventually gets weaker, and the denser particles that
gets cooled drift towards the center of the star, re surging the
contraction. This process continues until it reaches a stage where, the
contraction force gets balanced through the repulsions between
subatomic particles(electrons, protons, and neutrons). The star remains
stable again.
The star that gets balanced through the repulsions between 'electrons' is called as a
'White
dwarf' with a radius of about few thousand miles and with a density of
about hundreds of tons per cubic inch. The one that is supported
through the repulsions between protons and neutrons is popularly called
as a 'Neutron star' with a radius of about ten miles(only) and
density, hundreds of millions of tons per cubic inch.
This would
be the final stage of every known and unknown star that exist in our
known and unknown universe, if the subatomic particles able to move
with out a limit. But, according to Einstein's Theory of relativity,
nothing can travel faster than light.
Here comes the interesting
question: What if the star is so heavy that it requires the electron(or
proton or neutron) to move faster than light--to balance the immense
contraction(force)?
These kinds of movements or repulsions among
the subatomic particles are impossible as per the Theory of relativity
and hence the star ends up in a gravitational collapse, and forms an
infinitely dense region, popularly known as a 'Singularity'.
The
star that gets vanished in to a 'singularity' still exerts the same,
finite light trapping gravitational pull(can be more but not less) up
to certain distance in space creating a 'Black hole' around it. The
boundary of this 'Black hole', the 'Event horizon' is formed by the
paths of light just managed to move around but can't escape.
Thus the whole Black hole formation was almost based on Einstein's 'Theory of relativity'.
What
if the electrons under those special conditions(gravitational collapse)
could move with out a speed limit--faster than light ?
There will be no 'Singularity', no 'Black hole', but will be a 'Black star' or 'Dark star' that still can trap light.
