Recent images from the JWST have challenged our understanding of the early universe and even questioned the occurrence of the Big Bang event. Did the Big Bang really happen or have they been lying to us?
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| An artist's conception of the first instant of the cosmos. |
Our universe is so massive beyond our
wildest imagination, our solar system is a mere speckle relishing in its
insignificance. If all the stars in this universe was shrunk down to the size
of a grain of sand then the distance between each grain would be the size of the
pacific ocean such as the vastness of the cosmos. What if I told you even this
vast cosmos came into existence from a point even smaller than the smallest things
that we ever know?
The big bang theory is a model of the
universe in which a universe came into existence from an infinitely small point
by expansion to the size it is right now. No one could believe it when it was
proposed and now there is a good chunk of people who don’t believe it and to be
fair even I couldn’t believe it.
Big Bang generated a lot of opponents and
proponents from within the scientific community when it was first proposed
because even the most scientific people in this world had a hard time believing
it. Nothing can be this popular without generating a lot of critics and for
good reasons. There were several gaping holes in the theory itself that needs
fixing.
Firstly if indeed the entire transcendental
universe along with the observable universe was formed from an infinitely small
point in space then considering the present rate of expansion of the universe
then the universe should have expanded at a speed faster than the speed of
light at some point which the physicist calls the ‘inflation’. There are no
known theories or explanations for how inflation is even possible even if our
current models permit it. Secondly, if space-time didn’t exist before the big
bang or at the instant of the big bang according to the theory then our
universe should contain an equal amount of matter and antimatter which is not
the case in our present universe. There seems to be no known explanation for
the missing antimatter and the abundance of matter in our universe. Last but
not least there are these supermassive and compact galaxies and blackholes
found too early and too far away that they seem to be older than the universe
like there isn’t enough time since the big bang for their evolution from normal
stars and small galaxies but this can be explained by the fact that some these
early supermassive structures evolved formed from the inherent irregularities
in the densities of matter and energies from a very early and homogenous
universe quite differently from the evolution of present-day stars, galaxies,
and black holes.
Why are most so sure that the big bang happened?
Expansion Of The Universe
Our universe was long thought of as steady,
unchanging, and static. Even Einstein thought the universe was static and had introduced
a completely new ‘fudge factor’ into his equation of general relativity (which
was predicting an expanding or contracting universe) in order to make up for
the steady state of the universe. It was not until a young and brilliant astronomer
(who very nearly got a Nobel prize for his work on astronomy and astrophysics
but unfortunately during his time the Nobel physics prize did not cover the advancements
in the field of astronomy) in California found out that all the distant galaxy
was moving away from us by studying the redshifts of the light from these
galaxies. He also found out that the farther the galaxy was the faster it was
moving away from us. He found later that the only way to explain his
observations was that the universe indeed expanded as Einstein had once thought
and was not static as was previously believed. This had a significant backlash
in the scientific community as in every discovery but eventually, the belief
got established as more people got to know about the results.
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| Image showing the timeline of metric expansion of the universe. Credit: NASA / WMAP Science Team |
The discovery of the expanding universe
marked a significant turning point in astronomy and seed for a new advancement
in the origins of the universe. Previously when the universe was thought to be
static universe didn’t require any origin because it was very immutable. Things
changed when the universe was found to be expanding, when the universe is
expanding you can trace the present universe back in time and you will come to a
point in time where the universe was smaller than anything that can exist in
the present universe. This point is the very beginning of spacetime and the
laws that govern it, the big bang!
The Relic Radiation
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| Image of a cosmic microwave background radiation taken over a period of nine years. Credit: NASA / WMAP Science Team |
There is nothing more satisfactory than discovering something by accident that ends up changing the entire picture of the whole universe. It is one of the ‘eureka!’ in life that every scientist dreams. That is exactly what happened when to two American Astrophysicists when they tried to silence the excessive noise that they receiving in their antenna for an experiment they ended up discovering the remnant microwave radiation emitted from the big bang across the entire night sky!
In 1964, Arno Penzios and Robert Wilson
were working at that time for the Bell Labs in Holmdel, New Jersey. There were
trying to detect faint radio waves with a supersensitive horn antenna, to detect
those faint signals they had to get rid of all the unnecessary disturbances in
the surrounding. After eliminating all the possible disturbances in the
immediate surrounding they found out they couldn’t get rid of persistent steady
residual disturbances, strangely these were several 100 times larger than they anticipated. As
they couldn’t find where this disturbance came from suspecting some mystery
behind they ventured to find the source of the noise. They experimented again
after clearing some bird droppings that had been present in their antenna
pointing it into a particular direction in the sky in the hope of finding the
source by trial and error. After repeating the same experiments by pointing the
antenna in different directions in the sky they realized that the noise that
they were hearing didn’t come from anything within our galaxy as the radiation
was evenly distributed in the sky without much difference in its intensity.
Penzios and Wilson shrugged off the mystery without much thought.
At the same time, three physicists at
Princeton University just 60 Km away from the Bell Labs Robert H. Dicke,
Jim Peebles, and David Wilkinson wrote a paper predicting the presence
of leftover radiation from the beginning of the universe itself that can be
detected by high sensitive microwave telescope as the high energy radiation
emitted by the big bang would have red-shifted to the microwave frequency over
the age of the universe. When Penzios was told by his friend who was also a
physics professor at MIT at that time about a preprint paper written by three physicists
in Princeton that they began to realize that the ‘useless noise’ that they
found was a significant discovery in astrophysics. Penzios and Wilson
immediately invited Peeble and co. to show them their discovery, this convinced
Dicke, Peebles, and Wilkinson that the background noise that Penzios and Wilson
discovered was a signature of the beginning of the universe the big bang!
The
scientists wrote a joint paper detailing their new findings undersigned by all
of them five with added notes by Dicke, Peebles, and Wilkinson signifying the importance
of their new findings to the Astrophysics Journal Letters. Ironically enough,
the people who did the least work get the most recognition and the people who
did the most significant work will get none or at most some recognition. Dicke,
Peebles, and Wilkinson were the ones who gave the most important theoretical
prediction of the background signature radiation whereas Penzios and Wilson
accidentally stumbled on the observation but the latter group was recognized
the most and their discovery was overdramatized and blown to abnormal
proportions. Penzios and Wilson won the Nobel Prize for their discovery in 1978
just 14 years after their accidental detection whereas Dicke and Wilkinson died
before they were recognized for their work in 1997 and 2002 respectively and
Peebles had to wait more than four decades before he was awarded the Nobel
prize for his contribution in 2019 when he was 84 years old. Now I wonder why
Mahatma Gandhi wasn’t recognized enough.
The
microwave background radiation is the photograph of the big bang that can be
seen from every point in space and time, truly a relic in our time a ‘relic
radiation’. One of the most stunning and significant pieces of evidence of the
big bang and perhaps there couldn’t be better evidence that the universe had a beginning
than an actual picture of it, it is everywhere. This discovery along with the
discovery that the universe was expanding was enough to convince the scientific
world to believe in the big bang.