Ever since the early days of man. They have
always wondered how this world came into being.
Many have believed that God created the universe.
different religions in history have different
explanations for the creation process. Anyway
, at present , the modern scientific community
came together to support a particular theory
, that explains the origin of Universe. This
theory which is widely accepted by most scientists
is what is known as , the Big bang theory.
This theory was proposed out of the observation
that other galaxies are moving away from
our own at great speed in all directions , as
if they had all been propelled by an ancient
explosive force. The big bang theory was first
proposed by a Belgian priest named Georges
Lemaitre in the nineteen twenties , when he
theorised that the universe began from a single
primordial atom. The idea received major boosts
from Edwin hubble's observations that galaxies
are speeding away from us in all directions.
If everything in the universe is flying apart
, reversing the arrow of time would predict
that at some point all of these galaxies were
together in one incredibly massive entity.
Hubbles observations started a deluge of experimental
measurements that , over the last seventy
years have led to the conclusion by the vast
majority of physicists and cosmologists that
the universe began at a single moment , commonly
now reffered to as the Big Bang. Calculations
suggest it happened approximately 14 billion
years ago. A particularly important documentation
of the correctness of this theory was provided
rather accidentally by Arno Pen�zias and
Robert Wilson in 1965 , when they detected
what appeared to be an annoying background
of microwave signals regardless of where they
pointed their new detector. After ruling out
all other possible causes , Penzias and Wilson
ultimately realized that this background noise
was coming from the universe itself , and
that it represented precisely the kind of
afterglow that one would expect to find as
a consequence of the Big Bang , arising from
the annihilation of matter and antimatter
in the early moments of the exploding
universe. So , according to big bang theory
, In the first 10 raise to , minus 43 seconds
of its existence , the universe was very compact
, less than a million billion billionth the
size of a single atom.
It's thought that at such an incomprehensibly
dense , energetic state , the four fundamental
forces , gravity , electromagnetism , and
the strong and weak nuclear forces , were
forged into a single force. but our current
theories haven't yet figured out how a single
, unified force would work. To pull this off
, we had need to know how gravity works on
the subatomic scale , but we currently don't.
The laws of physics break
down in this circumstance , this state is
referred to as a singularity. It's also thought
that the extremely close quarters allowed
the universe's very first particles to mix
, mingle , and settle into roughly the same
temperature. Then , in an unimaginably small
fraction of a second , all that matter and
energy expanded outward more or less evenly
, with tiny variations provided by fluctuations
on the quantum scale. After inflation, the
universe continued to expand but at a much
slower rate.
As time passed and matter cooled , more diverse
kinds of particles began to form , and they
eventually condensed into the stars , and
galaxies of our present universe. So , this
is is what is big bang is , there occured
several other processes in between this expansion
, for some we have answers and for some others
, we don't. Now , let us into some of the
limitations of big bang theory. Radiation
in the early universe was so intense that
colliding photons could form pairs of particles
made of matter and antimatter , which is like
regular matter in every way except with the
opposite electrical charge. It's thought that
the early universe contained equal amounts
of matter and antimatter. But as the universe
cooled , photons no longer packed enough punch
to make matter , antimatter pairs. Many particles
of matter , and antimatter paired off and
annihilated one another. Somehow , some excess
matter survived , and it's now the stuff that
people , planets , and galaxies are made of.
But , Why did this asymmetry exist ?. It would
seem
more natural for there to be no asymmetry.
But , if there had been complete symmetry
between matter and antimatter , the universe
would quickly have devolved into pure radiation
, and people , planets , stars , and galaxies
would never have come into existence. The
way in which the universe expanded after the
Big Bang depended critically on how much total
mass and energy the universe had , and also
on the strength of the gravitational constant.
The incredible degree of fine tuning of these
physical constants has been a subject of wonder
for many experts. If the rate of expansion
of universe , after the Big Bang had been
smaller by even one part in 100 thousand million
million , the universe would have recollapsed
before it ever reached its present size. On
the other hand, if the rate of expansion had
been greater by even one part in a million
, stars and planets could not have been able
to form. The same remarkable circumstance
applies to the formation of heavier elements.
If the strong nuclear force that holds together
protons and neutrons had been even slightly
weaker , then only hydrogen could have formed
in the universe. If , on
the other hand , the strong nuclear force
had been slightly stronger , all the hydrogen
would have been converted to helium , instead
of the 25 percent that occurred early in the
Big Bang , and thus the fusion
furnaces of stars and their ability to generate
heavier elements would never have been born.
Finally , even if there are many limitations
for the the big bang theory or there are many
phenomenon that this theory can't explain.
It is still the best theory that explains
about origin of universe. So , Thanks for
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