Big Bang Theory For the Layman (but not Dummies)

In the days when science, philosophy and theology came packed in one envelope, our ancients conceived a substantially common model of the universe which only differed a little from place to place, from time to time and from one concept of God to another. The model was the most obvious and easily conceivable – a stationary earth at the centre of the universe and all the rest of the celestials playing ring a-ring o’ roses around it. With the limited distance that one could travel on the fastest of available horses, and with no instruments available to enhance one’s view of things around one, such a model served many purposes while satisfying human thirst for knowledge of the world around us. Their paradigms might seem totally erroneous to us since we possess far more data than they did; it’s not unlikely that the future generations of scientists and philosophers might discover that many of our own current concepts were wrong or inadequate for the interstellar travel that they could have mastered.

The ancient model or models worked very well for those who wrote almanacs predicting sunrise and sunset, solar and lunar eclipses, high and low tides, position of constellations that were supposed to determine a new-born’s future on a given day or hour, and so on. Religions approved of this model; so, it was set in concrete. There were stray noises – like that of Aryabhata of 4th Century India who wrote that it was the earth that rotated around its own axis.:’ “Like when you travel in a boat it appears as if trees on the banks move forward, when earth rotates, it appears as if the sun stars and the planet appear to move in the opposite direction.,”[1]Aristarchus of Samos (310-230 BC) is believed to have held a view, at least for some time, that the solar system was helio-centric – that is, centred around the sun, but discarded that view to stay clear of controversies and possible death by Hemlock when he wrote his treatise, On the Sizes and Distances of the Sun and the Moon. Aristarchus did conceive, as did Aryabhata, that the Sun was much larger than earth.

The Rebels

India’s Nilakantha Somayaji (1444-1544) was the first to suggest a heliocentric solar system in his work named Tantrasangraha (Collection of Doctrines). Ironically, the first person in the Christian world to propose a helio-centric model (planets revolving around the sun) was a Catholic priest. Nicolaus Copernicus (1473- 1543) who had died even before another contrarian of the century, Giordano Bruno was born. The secret of Copernicus dying in bed and not on a stake was that he did not assume a revolutionary air. He completed his helio-centric dissertation[2] by 1515, but arranged that it would only be published on his death-bed, with a caveat that Nicolaus himself did not believe in the theory.

Giordano Bruno (1548-1600) – philosopher, mathematician and astronomer, theologian by training, rejected the idea that earth was at the centre of the world. He also proposed many universes, and the possibility of rebirth.  For thus blaspheming the Biblical theory of a universe centred by the earth, Bruno underwent a series of tortures that would make an Islamic-State executioner shudder. In the name of the Lord so merciful, his tongue was gagged and jaws were wired shut (so as to prevent him from repeating the blasphemy) before he was burnt alive on February 17, 1600.

It was Galileo Galilee (1564-1642) who finally set the matter to rest by demonstrating with his newly invented telescope that the earth and all other planets moved around the sun[3]. For this offence, he was put under house arrest for the rest of his life. Galileo escaped inquisition that would have led to torture and burning at the stake just because he was once a favourite consultant on astronomy to Pope Urban VIII. After much persuasion and trials than ran through two decades, Galileo was made to state that the book, Dialogue on the Great World Systems, Ptolemaic and Copernican (1632)was merely designed to show his skill in dialectics. Galileo’s own defence was that he was a feeble old man of 69.  The book, and that of Copernicus – (“Six Books Concerning the Revolutions of the Heavenly Orbs”) (were banned. However, the story of his findings and incarceration raised interest among scientists in the field of astronomy.

Isaac Newton (1643-1727)

Ripe fruits had been falling ever since there were trees; humans have been watching apples, pears, hails and snowflakes fall. However, it took several thousand years after the development of human brain before a man named Isaac Newton paused to ask why an apple had to fall to the ground when it got detached from the stem.  No, it did not fall on his head as some wags would like to have us believe.

When something so commonplace as the fall of an apple, it set off a thought process in the contemplative mind like that of Isaac Newton.  Newton did not have many of the modern instruments. However, time was ripe; he came across the literature on the construction and uses of a reflector telescope invented by a monk (always a monk or a priest to the forefront of science!) named Niccolo Zucchi.who invented such a device in 1616. Newton constructed a reflector-type telescope himself, watched the wonders of the celestial bodies and developed his laws of motion and on gravitation.  The ideas were developed empirically, but Newton’s expertise in mathematics no doubt came to help and the telescope must have come handy for confirmation of his theory on how the celestial bodies stayed in what he believed to be in a steady-state orbital equilibrium. The original telescope often known as Newton’s reflector is on display in the Royal Society of London.[4] Newton also developed Calculus, somewhat simultaneously but independently from polymath philosopher Gottfried W. Leibniz (1646-1716).

Newton couldn’t help wondering why, despite his own law of continuous motion of bodies unless interrupted by an external force and that of gravitation, the universe failed to pull all the star configurations towards themselves over time leading to a massive inferno consuming the entire universe. When no logical answer came to his mind, he presumed that God made periodical adjustments between the planets, like a drill Sergeant would keep correcting with shouts the distance between each row and column of a band of marching soldiers. He went to his deathbed, probably not too convinced that divine interference in the laws of physics was the right solution.

Newton’ laws of motion and of gravity were easy to prove. His equations were simple and comprehensible; they offered ready solutions.   Hence, they were believed to be air-tight for all conditions and purposes. Apples always fell on the ground after they left the tree, whisky bottles fell and shattered when the drunken man lost his grip. Understanding and accurate prediction of the movements of celestial bodies became a matter of cool calculations. Horse carts, and in later years the steam trains and cars; by the twentieth century airplanes and rockets obeyed the laws without question.  The acceleration of bodies falling from different heights and the force of their respective impacts when they hit the ground were proof enough of acceleration through gravity. For the next two centuries, Newton’s theories were the unquestioned masters of everything in physics. The Gravitational Constant G empirically arrived at by Newton (9.80665 m/s2) became an accepted as a mean standard for all calculations for bodies falling on earth and, what is more, it worked..

Albert Einstein (1879-1955)

As more and better telescopic instruments were developed, the interest in the origin and the very future of the universe became a matter of great interest. In 1905, a young German Jew named Albert Einstein employed as a Technical Officer (IIIrd class) in the patent office in Bern, Switzerland published a brand new and much complicated theory called Relativity, showing that mass and velocity were relative; space and time were warped and not linear and that mass and energy were interchangeable. The theory was not all his own, just as Newton spoke of himself, he stood on the shoulders of giants before him – among them James Clerk Maxwell (1831 – 1879), Jules Henri Poincaré (1854-1912) and Hendrik Antoon Lorentz, (1853-1928), apart from Newton himself.   Ten years later, he included gravity and its effects into the theory, naming it General Theory of Relativity, relegating his first findings to a lower-ranking Special Theory of Relativity. The only thing that was absolute, showed Einstein, was speed of light through space – at 186,282 miles or 299,792 kilo metres per second. There is no force that could coax light to move at a greater speed. Every other motion was relative.

It is not my intention to explain the mathematics of General Relativity, which takes me a little time to get it right every time I try.  Let me, however, show you with a simple example how it interprets time and distance and high velocities that approach the speed of light.

Let us say you have invented a rocket that can fly at 99.5% of speed of light. (There is no hope of ever reaching the speed of light unless you are a massless photon – a particle of the electromagnetic wave, generally spoken as light.) If you were to fly that rocket and take it to to Andromeda at its maximum speed, you would reach the galaxy having travelled 2.6 or so light years, but you could still feel the fragrance of the perfume you wore on your lapel. Since you had travelled almost with time, your clock shows a few minutes or a couple hours past the time of lift-off.  However, you look back on the earth you left: you are seeing the earth that is .5.1 million years older (2.5 million years you took to travel from viewed from earth, and another 2.5 million years for the light to reach you) than when you left.  The human kind was probably extinct by overconsumption and global warming if they had not otherwise destroyed themselves in a nuclear war. Shocked and dismayed hoping you could do something, you get right back on your break-neck (literally) speed rocket and reach back almost instantly as per your clock – but find that the earth is by then more than 7.5 million years old. Think about it. That’s a good reason why you should never trust the UFO stories and never hope to meet an alien unless you find a planet attached to your closest star-pair Alpha Centaury some 4.3 light years away and can actually build a rocket that is a substantial fraction of the speed of light.

Cosmological Constant,

While working out the gravitational forces and building an equation for them, Einstein also came across the stumbling block that foxed Newton. If the universe was in a steady state, why didn’t the galaxies gravitate into each other and fall into a heap? He solved that problem technically by adding a constant to the equation. He called it the Cosmological Constant, and explained, “The term is necessary only for the purpose of making possible a quasi-static distribution of matter, as required by the fact of the small velocities of the stars” (Einstein 1917).[5] The numerical value of the Cosmological constant in Einstein’s equation was no larger than what was required to balance out  the relatively small gravitational force by a notional force to maintain the ‘quasi-static’ status of the celestial bodies (stars, galaxies, intermediate bodies). Einstein recognized that although, to his mind, the universe was by itself in a steady state, the stars did orbit the galactic centre with relatively small velocities. 

Publication of the theories of relativity gave an impetus to cosmological research around the world. The few who understood Relativity at that time, like Arthur Eddington, volunteered to test the theory.  His observations and theoretical calculations that led to the verification of a part of Einstein’s theory that electromagnetic waves (light) could be impacted by gravity were doubted by many, but soon further proofs followed, elevating the status of Einstein. Einstein himself was so sure of his theory that he is quoted by an assistant as saying that if observations did not prove his theory of gravity bending light, then he would feel sorry for God – for he was sure that the theory itself was beyond doubt  

 Each element of Einstein’s theory, fantastic and incredible as they may appear to the layman, continues to be proved and employed in science and technology just as Newton’s laws made possible designs of transportation and braking systems, aviation and space flight – virtually evry human activity.

Georges Lemaitre (1894-1966).

The probability of the universe coming into existence from the rapid expansion of a primeval atom was first proposed by a polymath Catholic priest, Georges Lemaitre (a priest again!) When he suggested his idea to Einstein and showed his calculations, Einstein commented wryly:

Your mathematics is perfect. But your physics is abominable.”

Three years later, when the expansion of the universe was proved by Edwin Hubble (1889-1953), Einstein, like a true scientist, ate his words and congratulated Lemaitre. The expansion solved many problems that vexed great minds such as that of Isaac Newton (1643–1727). Newton, in the absence of data that is available to science now, believed that God kept making periodic adjustments to stop collapse of the universe. Many years after Einstein and Lemaitre were long gone. the Hubble Space Telescope launched by NASA in 1990 positively confirmed the theory of expansion.

Fred Hoyle (1915-2001),

Lemaitre never called his proposal the Big Bang. The name, invented by the enigmatic scientist and science-fiction writer Fred Hoyle, was designed to ridicule the hypothesis. Foyle did not accept that the proofs such as CMBR (mentioned later in this blog) were adequate to establish that the universe began from the ‘Big Bang.’ As we shall see, the occurrence was not big, nor was there a bang. the Big Bang (a misnomer, designed to ridicule the very concept) was one unique event when the result preceded the cause.

Theory behind Big Bang

The primary reason for conceiving a big bang was this: If the universe is in a dynamic state of constant expansion as a function of time, then, by rewinding that function mathematically, you could arrive at a point that had no volume, but enormous mass, energy and gravity. All evidences – mathematical and empirical, pointed towards that possibility.

Father Lemaitre’s theory with some improvements and modifications has become the accepted probability for the origin of the universe in the minds of most scientists. Pope Pius XII (1876-1958) was so enamoured of the hypothesis that in his 1951 speech, to the chagrin of Lemaitre himself, he  hinted that the Big Bang was a burst of light and matter: ordained by God.

“Indeed, it would seem that present-day science, with one sweep back across the centuries, has succeeded in bearing witness to the august instant of the Fiat Lux[6], when, along with matter, there burst forth from nothing a sea of light and radiation, and the elements split and churned and formed into millions of galaxies.”

How was the Pope, interested though he was in science, to know that what burst forth (if that was what happened) was not a sea of light and radiation or that whatever churned did not form into millions of galaxies for several more thousand years.

Interestingly, at least two more Popes – including the incumbent Pope Francis subscribe to the idea of the ‘Big Bang.” On the other hand, there are still a few scientists who are not convinced about the Big Bang Theory. Renowned mathematician and astrophysicist F.R. Ellis (born 1939) says:

People need to be aware that there is a range of models that could explain the observations…….What I want to bring into the open is the fact that we are using philosophical criteria in choosing our models. A lot of cosmology tries to hide that.”


Actually, there is more than philosophy and conjecture in the Big Bang. Many of the elements of evidence, as in a high school physics laboratory, are designed to establish the pre-determined proof. For instance, the value of CMBR. (Cosmic Microwave Background Radiation) which is at about 2.72 degrees Kalvin as measured by two researchers in 1964 – Robert Wilson (B. 1936) and Arno Penzias. (b. 1934). This radiation which is found to be almost uniform through the universe, is believed to be the attenuated remnant of the massive amount of high-energy electromagnetic waves that were released after the plasma that was the state of the universe cooled to 1013 degree K and Hydrogen began to fuse into helium. Traveling through so many billion years of time and space, the high frequencies of that emission has cooled, losing energy (and hence wavelength) to Microwave frequencies and below. Even the ‘snow’ you might have noticed in old television sets could have been caused by the VHF (Very High Frequency) components of this radiation

As mentioned before Fred Hoyle scoffed at this conclusion; he said that even if the CMBR measured at 27 degrees, one could manipulate mathematics to come to the same conclusion. Hoyle’s opposition to BB was a paradox because his own suggestion of stellar nucleo-synthesis[7] could not have happened unless the universe was a ‘soup’ of hydrogen in its early stages and then blew apart under intense pressure and temperature. F.R. Ellis, a renowned mathematician and Templeton prize winner, discussed several alternative theories to the BB

General Consensus

Einstein got convinced of Lemaitre’s theory when he learnt of the discovery of continuous expansion of the universe by Edwin Hubble’ (1889-1953) in the year 1927. An expansion that continuously made galaxies move away from each other made sure that gravity could never catch up – as in the proverbial Zeno’s paradox   Once he was convinced that the universe was expanding, Einstein wrote to a friend that conceiving the Cosmological Constant was his greatest blunder. The master’s acceptance of the theory of expansion of the universe and rejection of his own suggestion of a universal constant that kept the universe in a steady state, gave it a fillip to it in the world of science. As we shall see, his admission of a mistake came too soon.

Accelerated Rate of Expansion

As it turned out, Einstein’s Cosmological Constant was not a blunder, but the figure he arrived at fell short of the quantum of force required to allow an expansion of the universe. After a lapse of 71 years in 1998, two research teams working on the Supernova project discovered that the universe was not just expanding at a constant rate, but expanding at an accelerated rate! This discovery won the 2011 Nobel prize in Physics for three[8] – with what they claim to be more advanced statistical methods. Although an Oxford University Physics research team led by Professor Subir Sarkar has contested the accelerated expansion theory, the hypothesis has taken hold in the computations and calculations of most cosmologists and physicists.

Dark Energy and Dark Matter

In the free space with no frictional resistance, continuous expansion from the moment it was given an impetus more than 13 billion years ago (13.7 billion – 380,000), and that could go on for any billion years more, Newton’s second law demands that there has to be a force to accelerate moving bodies. Where would you find such a force?

Dark energy is conceived as an anti-gravity energy that can not only cancel the effect of gravity, but also provide further constant force to accelerate the expansion of the universe. Initial calculations showed that some 68% of the mass of all the matter in the universe is this Dark Energy; 27% is some unknown dark matter and only 5% of the entire mass of the universe is what we can observe by whatever means available – all the galaxies with their stars, planets, dust, gas and stray bodies like meteors and debris. Even more research by Cosmologists Christian Marinoni and Adeline Buzzi of the University of Provence working with NASA’s Chandra X-Ray telescope on the growth of new clusters of galaxies   and binary galaxies  have concluded with an even more surprising figure : 74% of the entire universe consists of Dark Energy, 22% of Dark Matter, and only about 4% is what new see through the best of instruments, calculations and perceive with out senses.

It must be remembered that the adjective Dark to this unknown energy and matter is meant to indicate that science has not yet understood its properties except that it acts upon our universe with more force than all the fundamental forces[9] that science is aware of. Till a lot more is known about these Dark forces and how they affect the origin, preservation and death of the universe, they need not figure in our discussion on the BBT.

Deriving the Big Bang

The sky is a history of the past. The sun you see in the sky is 8 seconds old; the Venus has aged more than two hours and 30 minutes before you see it. The closest twin stars are 4.2 years older when you see it, and if you were to communicate with an intelligent alien there, she will answer you after 8.4 years, presuming instant response time at the other end. You are aware how a question-answer session conducted over satellite on your television channel shows a time gap. The news anchor asks a question; the reporter stares at the screen blankly for a few moments testing your patience and then comes up with an answer. This is because electromagnetic waves that relay their communication are situated in a geostationary orbit more than 36,000 kilometres away. Andromeda, the closest galaxy to our own Milky way (the faintly shimmering broad patch of a hazy ribbon that girdles our sky from horizon to horizon) is some 2.5 million light years from our solar system. When we measure the relative distance is time among the newer and old galaxies in the sky above, it is easy to make several observations and conclude that they are drifting apart as a function of time.

 We could rewind the continuous (or accelerated) expansion that we observe in our logical mind or by use of some mathematics, and get an idea of the development that happened during the period that began with the beginning of space and time as we know it. 

Why can’t we see the Big Bang?

That’s a genuine enquiry. If Hubble Telescope can see up to 10 to 15b Billion light years away, and if what we see is the history of seconds, minutes, hours, years and light-years gone by, why can’t we see the Big Bang that is believed to have happened some 13.7 billion years before?

Because the event was neither big, nor a bang. It was the sudden expansion of a tiny, massive Singularity – a unique phenomenon, like the core of a black hole, but much denser and under far greater pressure, all wrapped up into the smallest point imaginable. Where in space was this point located?  The singularity carried the space within it. So, its location was itself.

 The first phase of the inflation is called the Planck Epoch named after Max Planck (1858-1947). This ‘epoch’ is one-thousand-million-trillion-trillion-trillionth fraction of a second. (1/1043). Science has no means to find out what happens in such a short time. During the several such ‘epochs’ that followed, the expansion was great – some estimates say faster than light. To understand all that happened is a little complicated even for the most advanced science, for the speed with which it happened belonged to the realm of Relativity and the sizes were those could at best be understood by Quantum Theory. A unified Theory that could explain things is yet to be evolved.  Einstein died worried about it and Stephen Hawking’s hope that it (which he called the Theory of Everything) would be found by the end of 20th century did not materialise.

This is a summary of what modern cosmologists presume could have happened. 

Time 0 Quantum fluctuations, the tiny giant wakes up and stretches.
1/1043 sec. (1 Planck Epoch) Begins super-fast   inflation
10-30 sec Energy churns out matter and anti-matter; Some antimatter disappears (or goes on to form another universe), Soup of Quarks and electrons. Energy temperature is very high at 1027 degree C  
1 sec Temperature cools to 1013 oC  
3Mts Temperature is still too high to combine protons and electrons to combine into atoms  
300K years The plasma stage. The universe is opaque and hence not visible to the strongest telescope  
380K, years Quarks into Hydrogen proton, Energy in the form of electrons and photons. Background radiation of high-temperature electromagnetic waves., beginning of the birth of nebulae  
1 Bn years Stars, Formation of  Galaxies, The High-frequency background radiation begins to lose energy and increase in wavelength. the birth pangs of universe is visible to telescopes.  
4.6 B years The sun is born from a giant rotating cloud of gas and matter. Gradually, the disks that surround the sun due to gravity converge into planets according to the mass of each cluster and its energy level.  (Higher the energy, more distant the planet.  
13.7+ Billion years Background radiation at  Microwave frequencies observed at a very low temperature of 2.72o C. Some of this at VHF/UHF frequencies can be seen on old television sets as part of ‘snow’ when not tuned to a channel.

This is a rough picture, and, of course like everything in Cosmology, approximations of time, temperature and the actual events.

Big bang was a milestone, most probably not the very beginning of something out of nothing. In Einstein’s famous equation, E=MC^2, neither energy E nor mass M is a function of volume. So, it is also conceivable that the universe flew in from a near-infinitely small volume and is blowing like a horn to infinitely (to our mind, but infinity has no quantizable limit) large volume retaining virtually the same total amount of mass M and energy E while C remains constant.

Alternatively,, the universe could be one of no boundaries – just as our earth has a finite circumference, but no boundaries. It recycles, blowing up from a certain low volume to an incredibly high volume and then starts crunching (the Big Crunch) back to where it began.

Despite the universal expansion that is noticeable and the acceleration of the rate of expansion which is disputed by some, which leads to the guesswork of  the presence of a dark energy and dark matter in the universe (which, unless proven, is no better a concept than the concept of a Prime Mover called God),  we see that stars do come together to become giant stars and then crush themselves into black holes. Even if a Black Energy does drive the accelerated expansion, a stage must reach that it attenuates

Why should we worrry about the Big Bang?

Just because we cannot see beyond the hill, we must not conclude that there is nothing on the other side. Science will find what is out there some day. It could be other milestones on the other side of the Big Bang, or the Big Crunch, or even something our imagination has not yet caught on. The idea that there could be a gargantuan unseen force and unmeasurable energy in which our perceivable universe is immersed makes the picture even more interesting, even a little frightening. Stephen Hawking said this to the employees of Cedars Sinai Hospital who were treating him for his ALS

“Your universe is a great triumph, I want to share my enthusiasm and excitement about this great quest. So remember to look up at the stars and not at your feet. … Be curious. And however difficult life may seem, there is always something you can do and succeed at.”

[1] Aryabhatiya, Chapter Golapada (Verses on the sphere.

[2] De revolutionibus orbium cœlestium (On the Revolutions of Heavenly Spheres) published in Nuremberg, 1543

[3] Dialogue Concerning the Two Chief World Systems—Ptolemaic & Copernican.Galileo Galili, 1616.



[6] Fiat Lux – ‘Let there be light.’

[7] Stellar nucleo synthesis is a process Stellar nucleosynthesis is the process in  which heavier  elements are created within stars by combining the protons and neutrons together from the nuclei of  hydrogen and nuclear fusion under high temperatures and pressure. Heavier elements are created in different stars before they explode

[8] In the year 2011, Nobel Prize for physics 50 % went to Saul Perlmutter( born 1959),and the other 50% was shared by Brian P. Schmidt (born 1967) and Adam G. Riess (born 1969) for showing that the universe was expanding at an accelerated rate.

[9] The for fundamental forces are :: Strong Nuclear Force, Weak Nuclear Force, Electromagnetic Force and Gravitational Force. strong force is what  holds the nucleus together the nucleus of an atom. It also binds the quarks that make up Hadrons. weak nuclear force, is defined as the mechanism that  interacts between subatomic particles that is responsible for the radioactive decay of atoms.

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