EVIDENCE OF THE BIG BANG
In this chapter we aim to illustrate the process of the development of the Big Bang theory over the course of history and to present its main evidence.
1.THEORETICAL EVIDENCE: MISSING LINK IN NEWTON’S CONCEPT OF UNIVERSE
Newton imagined an infinite universe ruled by gravitational force. He thought that kinds of matter that attracted each other in a finite and stationary universe would eventually adhere to each other to form a single whole. But one could observe no such composition in the universe. He tried to sidestep the issue by stating that matter was scattered in an infinite universe. But this did not constitute an explanation of the problem: if every object was attracting every other object, how had the stars kept their distances from one another for ages? The idea of an infinite universe was not the solution. The gravitational force between the stars would draw them closer to each other in a given portion of space. If they got close enough, they would adhere to each other; but if they moved away from each other somewhat, they would go even further away from each other, since they would be released from the gravitational force. Thus, the notion of the indefinite expansion of the universe did not do away with the problems that the gravitational force would generate; assuming that the universe was infinite, everything would collapse sooner or later into a single whole. But this did not fit in with the age-old universe presented to the view of man.
Newton’s idea of an infinite universe created difficulties in establishing the beginning of creation. On the other hand, the idea of creation by an omnipotent God of an infinite universe had come to be accepted by a considerable number of theologians. Scientists and philosophers who succeeded Newton were under the influence of Newtonian physics and espoused the idea that the universe was infinite. This assumption continued until the formulation of the Big Bang theory.
CORRECTION BROUGHT TO NEWTONIAN PHYSICS
Einstein also came under the influence of Newtonian physics. It was in 1916 that Einstein put forward the model of a static universe. Soon after, however, he realized that such a static universe was eventually destined to collapse into a single mass under gravitational force. His introduction into his equations of the “cosmological constant” to fit his model of a stationary universe in his theory was not based on any logical reason, observation or theoretical necessity. Einstein postulated this cosmological force of repulsion to cancel out the attractive force of gravity. The only reason for Einstein’s positing the “cosmological constant” was his confirmed belief in Newton’s infinite static universe, as he was resolute that any contrary view could not find justification. Later, Einstein was to acknowledge that this biased opinion about a static universe and “cosmological constant” had been the greatest blunder of his life.
In 1922, Alexander Friedmann, Russian meteorologist and mathematician, noticed something that Einstein had ignored and refused to acknowledge in the beginning: the fact that the universe might be expanding. Friedmann worked with the relativity equations of Einstein and found that the expansion of the universe was the necessary consequence of these equations; the universe was not static so, then, it was dynamic; this model of the universe provided the missing link for the Newtonian system. It became clear that the laws of gravitation did not contradict the picture that the universe presented. The dynamism of the expansion prevented the galaxies from collapsing into a single whole.
This discovery, based on Einstein’s equations, agreed with the Einsteinian physics. The paradox that Newtonian gravitational laws had been facing was thus solved by Einstein’s formulas, and it was understood that there was no need for a “cosmological constant.”
LEMAITRE’S SOLUTION
Independently from Friedmann, Georges Lemaître, Belgian astrophysicist, developed the notion of a ‘primeval atom’ that had exploded, establishing thus the Big Bang theory that marked the beginning of the expanding universe. Like Friedmann, Lemaître had also studied Einstein’s formulas, and it was these formulas that inevitably led Lemaître to conclude that the universe was expanding.
An expanding universe counterbalanced gravitational force, which prevented the matter scattered in space from condensing into one single mass. The expanding universe continually grew in size and was never the same as a moment earlier. This connoted, at the same time, the fact that the universe that preceded the expansion was smaller in size. This meant that originally the universe had been a single mass. The said results, which formulated the Big Bang theory, were the consequence of Einstein’s formulas.
Lemaître was the most prominent specialist in the observatory of the Vatican. The theory he propounded found a ready home in the Catholic Church, which never failed to support him. The Catholic Church was the first among the religious circles that acknowledged the paramount importance of the Big Bang theory (1920s), and in 1951 the Church officially recognized that the theory was in perfect accord with religion.
EINSTEIN’S FORMULAS
Einstein’s formulas explained the gravitational force in a clearer light than did Newton’s. For instance, the failure of Newtonian formulas to exactly explain the orbit of the planet Mercury was later explained precisely by Einstein’s formulas.
According to Einstein, the mass of objects influences space by causing it to be curved. Space is not an absolute void; it is dependent on masses by which it is influenced. This phenomenon, one that seems at first difficult to comprehend, may be illustrated as follows: imagine a bi-dimensional sheet representing space. Let two persons stretch it from either end. Let us place an apple on it. The sheet will automatically lose its tautness and becomes distorted especially near the apple. If we replace the apple with a heavy rock, the distortion will be so great that it will become almost impossible to go on holding the sheet. We can deduce from this the fact that as mass grows, the distortion is larger.
According to Einstein’s explanation of gravity we are revolving around the sun, since it is the sun that causes the greater distortion in near space. Had the universe been static, matter (stars, planets, etc.) would have collapsed at the bottom of the greatest pit of time and space. Newton’s physics demonstrated the mutual attraction between celestial bodies, while Einstein’s physics produced the mathematics that explained the manner in which celestial bodies exerted influence over time and space.
INTERLINKING OF MATTER, SPACE AND TIME
Matter, space and time were interlinked by Einstein’s formulas, but prior to the 1920s it was the concepts of “absolute space” and “absolute time” that dominated. It was believed that space and time stemmed from infinity and perpetuated their infinity and were not affected by the motion and gravitational force of celestial bodies. Einstein’s relativity theory demonstrated the error in conceiving of space and time as separate and absolute entities; whereupon there emerged the space-time concept. The space-time affected the motion of celestial bodies, and they were affected by all the phenomena in the universe. These phenomena cannot be comprehended without the space-time concept, and according to the “relativity theory” one cannot refer to a space and time outside the confines of the universe.
Einstein’s formulas led us to the conclusion that the universe expanded. Now, were one to reverse the process and conclude that space dwindles into nothingness, the concept of time would necessarily also cease to exist. It ensues from this that the Big Bang was not only the origin of matter, but also of time. This fact was further corroborated by the theoretical demonstrations based on the mathematical equations of Roger Penrose and Stephen Hawking.
The theory of relativity paved the way for an important mental revolution by the fact that time is not absolute, that it changes along with the speed and gravitational force. The Newtonian concept of absolute time, the antinomies that Kant’s philosophy had posited on the postulate of absolute time, lost their value in the wake of Einstein’s revolution.
Experiments conducted afterward justified Einstein’s claims. Two precision atom clocks were set at exactly the same time: one was kept on the earth’s surface and the other boarded a plane that left London for China. These clocks set by John Laverty were of such perfection that the admissible error involved was 1 second per 300,000 years. As the plane flew at high attitudes, it was not affected by gravity as much as an object on the surface of the earth. As the gravitational force influenced time, it was expected that the clocks would mark different times. The difference anticipated was insignificant and, therefore, could only be established by a precision instrument. The difference in question proved to be 1/55.000.000.000 of a second. This was an empirical evidence of the correctness of Einstein’s relativity of time. Such a phenomenon could not even have been fancied before, since the former conception conceived of time as absolute and unaffected by gravitational force. Additional experiments were to confirm Einstein’s theory.
Einstein’s discovery introduced momentous change into the minds of many. Reversal of the progressive expansion of the universe to the beginning of time ended with the extinction of space. Time, coexistent with space, had a common origin according to the relativity. The concept of absolute time that Einstein’s formulas had invalidated lost its eternal character. Time became a relative concept that had a beginning. This, however, did not mean, as some had imagined, that time was merely a product of the mind and that it had no existence in the world outside. Quite the reverse was the case, given the fact that this approach linked space, time and matter together and explained it in mathematical terms; time was as real as the existence of matter in the outside world. The scientific demonstration of the fact that not only matter but time also had a beginning and that both had a common origin was the achievement of the Big Bang theory.
SOLUTION OF OLBERS’S PARADOX AND THE GRAVITATIONAL POTENTIAL PARADOX
The Big Bang theory owed its origin to theoretical considerations, without observational evidence. This same theory also resolved Olbers’s Paradox, a subject that had been hotly debated for years. This paradox, expressed by Heinrich Olbers in 1826, asked the following question: “Why is the sky dark at night?” In an infinitely large and unchanging universe, uniformly populated with stars and galaxies, the sky should be dazzlingly bright. Olbers suggested a solution for this paradox: he thought that the enormous amount of dust in the universe must be absorbing the greater portion of the light emitted by the stars, causing the sky to darken.
It was discovered afterward that even this dust would get hot because of the radiation it had absorbed and would radiate with the same intensity. The paradox came to be solved following the Big Bang’s postulation that the universe must have had a beginning and that it was expanding. So, the fact that the night sky is dark indicates that the universe cannot have an infinite number of evenly distributed stars over an infinite period of time.
Johann Friendrich Zöllner’s (1871) paradox about gravitation was also invalidated by the expanding universe model (the gravitational potential paradox). Zöllner maintained that if we imagined the stars in an infinite and static universe evenly scattered in space, as Newton had assumed, there should have been infinite gravitational potential at every point of the universe. Such a postulate was hardly compatible with common sense and observations; in this way the Big Bang model that postulated an expanding, dynamic and finite universe also resolved this paradox.
HAWKING’S WONDER
Hawking wondered at the fact that nobody (not even Newton) had ever posited that the universe was expanding, before the twentieth century. He commented: “We know it is impossible to have an infinite static model of the universe in which gravity is always attractive. It is an interesting reflection on the general climate of thought that before the twentieth century no one suggested that the universe was expanding or contracting. It was generally accepted that either the universe had existed forever in an unchanging state, or that it had been created at a finite time in the past more or less as we observe it today.” In a different context he had the following to say: “The discovery that the universe is expanding was one of the greatest intellectual revolutions of the twentieth century. With hindsight, it is easy to wonder why no one had thought of it before. Newton and others should have realized that a static universe would soon start to contract under the influence of gravity. But suppose instead the universe expanding.”
The fact that the universe could not be static was inherent in Newton’s law of gravity. Yet, Hawking was puzzled at the fact that the expansion of the universe had not been conceived by Newton and his successors. Hawking thought this mystery should have been solved long before the 1920s.
In the beginning, the Big Bang was based solely on “theoretical evidence.” Observations were to be made later, as the theoretical considerations found their justifications. Plato thought that the universe had been constructed according to mathematical principles laid down by God. Einstein said that unless we turn to good account the observations we make on a theoretical basis, phenomena will not be comprehensible, given the fact that theories are explained by mathematical principles; the mathematical approach joins the point of intersection towards which Plato and Einstein converge.
1. The said theoretical evidence solved the paradoxes related to Newton’s law of gravity.
2. They were based on Einstein’s formulas (these formulas are supported by experiments).
3. They established the fact that time had a beginning simultaneously with matter.
4. They solved Olbers’s paradox.
5. They also solved the gravitational potential paradox.
In this way, paradoxes in the cosmology of the universe were solved, the laws of gravity became comprehensible and mathematical formulas of the theory of relativity found their application. The beginning of the universe was thus seriously explained in scientific terms for the first time.
2.EVIDENCE OF THE EXPANSION: MENTAL REVOLUTION BASED ON THE TELESCOPE
The “theoretical evidence,” which was the first piece of evidence of the Big Bang, was based on Einstein’s formulas; this evidence posited that the universe could not be in a steady-state and that it was in the process of expansion. When this evidence was introduced for the first time, experimental data were not available; all that existed were theoretical principles based on mathematics. Spurred by scientific developments, and especially by the invention of the telescope, the observation of the celestial bodies had created a new enthusiasm. The marked developments in the telescope provided new knowledge of the celestial sphere. By adding mirrors to the telescope, Newton succeeded in obtaining images that were more highly magnified than those available to Galileo. Stars were seen more readily, inviting scientists to discover the mysteries of the universe and the stars.
In 1920, the most sophisticated of telescopes was at Mount Wilson in California, USA; Edwin Hubble (1889-1953) obtained permission to use it in research that would lead to revolutions in our thought. These revolutions would be led by new knowledge based on observations.
HUBBLE’S OBSERVATIONS AND THE DOPPLER EFFECT
Observations made by the Hubble telescope demonstrated for the first time that the number of galaxies in the universe greatly exceeded one hundred million. His statements gave rise to speculation that the time had come for this man to retire.
Hubble, disregarding the controversy he was provoking, continued his research. In 1929 he noticed that the external galaxies appeared to be receding from the Milky Way and that the further away they were, the faster they receded. Hubble obtained the same results in all the galaxies he observed. This discovery of Hubble’s was to lead the way to a conceptual revolution of great scope. At first, the importance of this unexpected discovery was not fully realized. The best illustration of Hubble’s universe was made by using an inflating balloon. Mark a speck on the surface of a balloon and put dots around it haphazardly. As the balloon keeps inflating you’ll see that the dots will recede away from each other. The universe was expanding as such.
Hubble discovered the expansion by the Doppler effect. The Doppler effect is the change in wavelength observed when the distance between a source of waves and the observer is changing. The wavelength increases as the source or the observer move apart from other and decreases as they move closer to other. The changing pitch of the siren of a passing motor vehicle is an example of the Doppler effect on sound waves. In this respect, there is no difference between sound and light, as both propagate in waves.
As the wavelength of the light source drawing near decreases, it shifts to the blue color in the light spectrum. The wavelength of the receding light source increases and shifts toward red. Hubble examined the light coming from the stars using the Doppler effect and noticed that the light always shifted to red; this meant that all the stars were receding along with the galaxies. The anticipation was the shifting toward blue of the light coming from the stars of some galaxies, while toward red of the light coming from other stars.
Observations that succeeded those of Hubble, Milton Humeson’s and others’, confirmed this result. In 1948 the biggest telescope of the world was established at Mount Palomar and the observations carried out by this telescope confirmed the results as well.
LEMAITRE AND BOXER HUBBLE
Edwin Hubble’s initial aspiration was to be a boxer. One wonders how many adversaries he would have knocked out had he done so! But one thing is certain; his observations knocked out a great number of scientists who believed the universe to be static and stationary. The concept of a steady-state universe, confuted by theoretical evidences, was, in a sense, knocked down by Hubble.
All observations carried out up until today have confirmed Hubble’s findings. At first, atheists, who foresaw the philosophical consequences of Hubble’s discoveries, took issue with them and refused to accept the concept of an expanding universe. This was a concept that atheistic scientists, convinced of an unchanging, eternal and boundless universe, were to have difficulties accepting. When Hubble exposed the findings of his observations for the first time, he was derided and the results he had obtained were made light of.
However, the new discovery caused a scientist by the name of Lemaître to sparkle with excitement. As we have already seen above, Lemaître and Friedmann had, independently from each other, theoretically posited the necessity of an expanding universe by mathematical formulas. Lemaître was not content with a theoretical approach; he also made use of Hubble’s observational data and ended by explaining that the Big Bang theory was substantiated by both theoretical and observational evidence. Theoretical calculations matched eventually with the results achieved by the telescope.
At first Hubble himself did not realize the scope of influence that the knowledge he had acquired would be exerting on the physics and the philosophy of the 20th and 21st centuries. It seems that Lemaître was the first person to understand its importance.
ENCOUNTER OF LEMAITRE, EINSTEIN AND HUBBLE
As I have already pointed out, even Einstein was at pains at first to confirm the truth of this theory, despite the fact that it was the product of his own formulas, for, he, like Newton, maintained that the universe was static and stationary. Lemaître, Einstein and Hubble met one day at the California Institute of Technology. Lemaître gave a detailed account of the Big Bang theory. He said that the universe owed its beginning to a “primeval atom,” which, as a consequence of disintegration, had broken into parts that eventually became galaxies that expand according to the standard equations of general relativity. He meant thereby that the universe was created on a day that had no yesterday. He had made all the calculations needed for the purpose; he combined the data of Hubble, who was among the audience, with Einstein’s formulas. Lemaître was surprised to see Einstein rise and declare this explanation to be the brightest and the most convincing he had heard thus far.
The meeting at the California Institute of Technology was a breakthrough. Lemaître, the father of the Big Bang theory; Einstein, who had a share in the production of the “theoretical evidence” through the application of the mathematics of the theory of relativity; and Hubble, who had contributed to the demonstration of the theory by his “observational evidence,” had come together and confirmed the truth of the Big Bang theory.
HUBBLE’S LAW
The findings of Hubble and Vesto M. Slipher and Milton Humason, who collaborated with him at the Mount Wilson observatory, have another important aspect: the Hubble Law, the result of his observations. In 1929, he announced his famous law: the more distant a galaxy, the greater, in direct proportion, is its velocity of recession.
This law permitted scientists to measure the speed at which galaxies moved away from each other, and to spot the place that a particular galaxy would be occupying at the end of a definite time. We can estimate the position of a galaxy after a billion years. The same reasoning may also be reversed. If we go backward instead of proceeding ahead we end up at the beginning of creation. By this formula it is possible to calculate the age of the universe. The moment at which the universe was created can thus be defined.
The age of the universe can be established by using Hubble’s constant. The exact calculation of Hubble’s constant involves difficulties; that is why the construction of the exact time at which the universe was created has been a controversial issue.
Scientists have used different methods to calculate the age of the universe. Nevertheless, the results they have achieved vary between 10 to 25 billion years; none of the various calculation methods have gone beyond these limits. Research conducted after the 1990s indicated that the age should be around 15 billion of years.
NO MOMENT OF THE UNIVERSE IS EQUAL TO ANOTHER MOMENT
The expansion of the universe, which had, at the beginning, been posited as “theoretical evidence” deduced from mathematical calculations, was substantiated by observations that eventually led to the reckoning of the age of the universe and its establishment within a time bracket. The question now was not, therefore, whether or not the universe had a beginning, but how to exactly calculate its age.
The most recent observations have added new evidence to the expansion of the universe. According to the Big Bang model, the universe expanded rapidly from a highly dense primordial state that resulted in a significant decrease in density and temperatures. When you look at the galaxies in the farthest corners of the sky, please bear in mind that you are, in fact, watching the past of the universe. As the light of the farthest galaxies is traveling from an extremely long distance, what we observe in fact is the state of galaxies billions of years ago. Our observation of this fact proves that this state of galaxies presents a denser aspect of the universe. The universe that was denser billions of years ago attained its present density after continuous expansion. This is another confirmation of the Big Bang theory.
Continuous expansion of the universe is a discovery that has revolutionized astronomy and deeply affected man. Such an earth-shattering discovery has but few precedents in the history of science. A similar breakthrough was perhaps the substitution of the geocentric system with the heliocentric system. I maintain that the revolution in thought processes that this would lead to was of an even greater scope. (However, its far-reaching significance may as yet not be as conspicuous as the Copernican revolution.)
The continuously-expanding universe reminds one of Heracletus (540-480 BC), who said, “You cannot step into the same river twice.” The expanding universe is changing every moment, and every moment we are in a universe of differing dimensions. No split second is the same as the one that preceded it. No two moments of the universe are equal. This revolutionary change is being evidenced by observations that take us much further than Heracletus’s statement. The expansion and continuous alteration generate other far more reaching consequences related to the origin and the end of the universe.
3.COSMIC BACKGROUND RADIATION: DISAPPOINTMENT GENERATED BY THE OVERTHROW OF THE CONCEPT OF AN ETERNAL UNIVERSE
The Big Bang theory was launched at a time when Marxist atheism was gaining ascendancy and positivism was espoused by a great many scientists as the only valid philosophical system. A universe that had no beginning in time was gladly maintained by positivists and atheists as it shoved aside God. Sir Arthur Eddington declared that the idea that the universe had a beginning was “philosophically repugnant.” The antagonism toward the Big Bang theory originated from ideological concerns and atheistic psychology rather than scientific interest.
In a radio broadcast, Fred Hoyle, who himself advocated the Steady State model, referred sarcastically to the new findings with the expression “Big Bang.” The expression later gained acceptance.
WHERE IS THE FOSSIL OF THIS EXPLOSION?
During the time in which the Big Bang theory was being formulated, demonstration was made of the formations of elements in the course of the life process of stars. The contribution of Fred Hoyle and his team on this subject had been very significant. The Big Bang theory explains the origin of hydrogen, an element which was not produced by stars, but contributed to their formation. The Big Bang compensates for the gaps that existed in Hoyle’s suppositions and gave a perfect account of the formation of elements. According to the subatomic theory, in order to be obtained, hydrogen requires a medium of immense heat. The Big Bang model posits the necessity of the existence of such a medium of immense heat at the origin of the universe.
Hoyle maintained that the solution of this problem could not be found in the Big Bang theory and he continued to insist on his antagonism. If the Big Bang had produced an immense heat at the beginning, he said, the explosion should have left a fossil behind.
As a consequence of the sarcastic approach of Fred Hoyle, not only the term “Big Bang,” but the term “fossil” was also coined. When “cosmic background radiation” was discovered, many scientists termed it “fossil radiation.” In fact, Hoyle’s objections played the role of a boomerang, as they ended up validating, rather than invalidating the Big Bang theory, thus putting an end to his espoused Steady-State model.
GAMOW’S THEORETICAL CALCULATIONS
It was Gamow who first postulated the existence of the cosmic background radiation based on mathematical calculations. Gamow and Alpher proposed on 1 April 1948, the “alpha, beta, gamma” theory that suggests the possibility of explaining the abundance of chemical elements as the result of thermonuclear processes in the early stages of a hot, evolving universe. These ideas were developed and became part of the Big Bang model of the universe. They predicted that, as the universe expanded, the cooling of the Big Bang would yield a faint background radiation with the current temperature of about 5 Kelvin.
An article by George Gamow and colleagues narrated the way the atoms interacted at the beginning of the Big Bang in the light of recent findings of nuclear physics, exposing the fact that the value of heat emitted during these reactions could be measured in terms of billions of degrees. They pointed out that the radiation, involving an immense energy, filled the universe and claimed that even today a remnant of this high-energy thermal radiation was still there in space. In brief, Gamow postulated the necessity of the existence of the “fossil” at which Hoyle had poked fun.
All radiations that succeeded the Big Bang would have definite points of origin from which they emanated. But the most significant characteristic of the radiation caused by the Big Bang was its spread throughout the universe.
FOSSIL RADIATION FOUND
In the 1960s, Robert Dicke and colleagues deduced that a Big Bang origin of the universe should have left an observable remnant of microwave radiation, detectable all around us. The origin of the universe was intensely hot and replete with hot electrons, protons and photons of high energy. As the universe expanded this radiation was to cool down, enabling us to observe it in the microwave zone of the electromagnetic spectrum. It is said that the astronomers from Princeton were not aware of the fact that Gamow had a similar concept. It is an established fact, however, that Gamow and colleagues were aware of the existence of this radiation, although they failed to propose its experimental demonstration.
Robert Dicke and colleagues were the first to use special instruments to try to find the cosmic microwave background radiation. Dicke, Roll and Wilkinson constructed the microwave radiation detector that Dicke had designed in 1965. However, the discovery, which they believed would secure them the Nobel Prize, was to fall to the lot of others, namely, to two engineers: Arno Penzias and Robert Wilson, employed at the Bell Telephone Laboratories in New Jersey. Penzias discovered “cosmic microwave background radiation” while investigating an unexpected excess. The interference caused by this phenomenon thwarted their research. When they failed to dispose of this interference they called up Dicke and his friends at Princeton, as they knew that they were specialized in radiations in space. Dicke and colleagues, having heard of the findings of Penzias and Wilson, realized that the latter had discovered the radiation that they themselves had been looking for. Thus, the fossil, at which Hoyle had poked fun, was discovered by Penzias and Wilson, who were awarded the Nobel Prize, while Dicke and his friends missed the chance. There have been many scientists who acknowledged this discovery as “compelling evidence.” The defense of the Steady-State model became impossible following t he discovery of the “cosmic microwave background radiation.” The radiation in question could be observed in every direction of the universe. The temperature of the radiation was -270 (3 Kelvin). This value was quite near the temperature -268 (5 Kelvin) that Gamow and colleagues had calculated. Alpher and Herman said: “Everyone agrees that 1965 was an important year in the historical development of cosmology; indeed, some take it as the birth year of modern cosmology.”
4- EVIDENCE OF COSMIC MICROWAVE BACKGROUND RADIATION: SLIGHT FLUCTUATIONS IN THE RADIATION
The discovery of cosmic background radiation was a significant evidence of the Big Bang. Further research conducted on this radiation was to supply new evidence in corroboration of the Big Bang model. Following the observations of Penzias and Wilson, Roll and Wilkinson from Princeton University built precise instruments to carry out the experiment. This was the first of a number of experiments that were to validate the findings of Penzias and Wilson.
After the discovery of cosmic microwave background, scientist began searching for fluctuations of the radiation, as they were necessary for the formation of the universe. Had matter dispersed in every direction homogenously following the Big Bang, the formation of galaxies, stars and the earth would not have been possible. For the said formation, fields of varying densities were necessary. The minutest of divergences in temperature during the initial development of the universe starting from a single point would give ample evidence to attest to this. Spots comparatively hotter would have had greater energy, whose contents of particles would be more numerous than in the cooler portion. This process would give the way to the formulation of the galaxies.
FLUCTUATIONS DISCOVERED
The detector that Penzias and Wilson used could not possibly detect the fluctuations anticipated in the cosmic microwave background. To obtain precise measurements, it was first necessary to eliminate the sources of interferences in the earth’s atmosphere. Instruments of great size had to be lifted into the sky in helium balloons. A plan was constructed whereby U2 aircraft would search for “cosmic microwave background.” To carry the precious detector, a cockpit with a specially designed compartment was constructed, for even the windowpanes of the aircraft might impair an instrument of precision. It became clear that the motion of the aircraft and the time that would allow measurements was limited. The aircraft could not remain suspended in the air like a balloon; it had to draw the same trajectory over and over again which would drain up its fuel before the completion of the measurement. The only realistic solution was to use a satellite. The anticipated venture was realized in November of the year 1989 by the installation of an instrument on the Cosmic Background Explorer satellite (COBE) by John Mather. The instrument developed by Mather succeeded in sensitively measuring the temperature of the cosmic microwave background, which corresponded to a temperature of 2.725 Kelvin. COBE stayed in space for three years; the data it provided were more than sufficient, as they proved not only the existence of the cosmic background radiation, but also its emanation from every direction of space. Infinitesimal fluctuations were also detected. The picture drawn by computers based on data provided by COBE also indicated the fluctuations in the former map of the world. To differentiate between the hotter and cooler portions, pink and blue colors were added to the picture. The data that COBE had found in the universe were re-examined and meticulously studied; the results were satisfactory. Fluctuations did exist in the cosmic microwave background and this would permit the formation of galaxies. The Big Bang model had won another victory.
George Smoot hit the headlines all over the world when his
data processor produced the pink and blue image of the fosil radiation in the universe. A cosmological observation like this had never been witnessed before. Next to the picture was Stephen Hawking’s comment on this discovery: “This is the greatest discovery of the century, and perhaps of all times.”
The project leader of the COBE satellite, George Smoot, declared that this discovery was an evidence of the fact that the universe had had a beginning and added that it was as if one was
looking at God.
SATELLITE AND COMPUTER-BACKED DATA
The satellite, a marvel of engineering, and the computer, a miracle of electronics, joined hands with the fine calculations of mathematics to promote the Big Bang. The picture of the universe was now clearer than ever.
The discovery of the fluctuations required for the formation of galaxies was something that not even those who had posited their indispensability had been expecting. The alpha-beta-gamma thesis that had put forth for the first time the necessary existence of the cosmic microwave background radiation had occupied its privileged place in history. In 1978 Penzias and Wilson were awarded the Nobel Prize for their discovery of 1965. The COBE satellite launched into space at the cost of millions of dollars in order to measure the cosmic background radiation had thus measured the “fossil radiation” and the fluctuations in it with great precision. The discovery of the cosmic background radiation and its study were of paramount importance for the Big Bang theory. The cosmic microwave background had other evidence in store for us.
TEMPERATURE OF THE FORMER COSMIC MICROWAVE BACKGROUND RADIATION
As we have already noted, one of the most significant data
provided by the Big Bang model was the fact that the origin of the universe was extremely hot and dense and that these had decreased as the universe expanded. The temperature of the cosmic background radiations is continuously falling, and, at present, it is equal to 2.7 Kelvin. When we look at the light coming from the galaxies far in space, we must remember that we are actually looking far into the past. The light coming from the remote galaxies is coming from a distance of billions of years. It may well be that the galaxy we are observing at the moment does not actually exist, and that we are seeing the light that had departed on its journey billions of years ago. In brief, we are looking far into the past.
In the past the universe was, according to the Big Bang theory, much denser and hotter. Were we to measure the temperature of the cosmic microwave background in one of the farthest galaxies (galaxies of the past), we should be able to find a much higher temperature. In the spring of 1994, researchers were able to succeed doing this. The temperature of the cosmic microwave background radiation was 7.4 Kelvin, which today is but 2.7 Kelvin.
This observation was made thanks to the Keck telescope, the biggest optical instrument of the time. In 1996, the same team of astronomers succeeded in measuring the temperature of a more remote galaxy; the value they found slightly exceeded 8 Kelvin. The scanning of even more remote zones by another group of astronomers led to the discovery of a temperature of 10 Kelvin. All these data confirmed the Big Bang; the farther we went, the higher the temperature encountered. The study of the history of the cosmic background radiation proved to be an additional evidence of the Big Bang.
COMBINING THEORY AND OBSERVATION
So the mathematical theory was coupled by observations as regards the cosmic background radiation: We may summarize this process in the following manner:
1. On a theoretical basis: Gamow and Princeton researchers postulated that there is a remnant radiation from the primeval fireball which spread over the entire universe, and made a calculation of its temperature. On an observational basis: This radiation, the existence of which was initially detected by Penzias and Wilson and afterward came to be confirmed by COBE observations, was diffused throughout the entire universe and the calculations made by Gamow and Princeton researchers were very near to the temperature of this radiation.
2. On a theoretical basis: It was postulated that fluctuations must have been at the initial temperature of the universe for the formatting of galaxies. On an observational basis: In 1992 COBE detected the temperature fluctuations at the initiatory phases of the universe.
3. On a theoretical basis: Given the fact that the past of the universe involved higher temperatures, so should the temperature have been of the past cosmic microwave background radiation. On an observational basis: In 1994 the study of light coming from remote galaxies confirmed that the cosmic microwave background radiation was higher in the past, as was expected. The subsequent observations confirmed this.
5. EVIDENCE FROM THE QUANTITY OF ELEMENTS AMOUNT OF HYDROGEN
The proportions of the elements in space are established by the “Fraunhofer lines” discovered by Fraunhofer. These lines were the fingerprints, so to speak, of the elements. It is possible to detect the nature of the elements in the light source by analyzing this fingerprint. It has been observed that the composition of the sun and the stars are one and the same. Their basic elements are hydrogen and helium. The sun was part of a subgroup of galaxies of stars. The universe was a medium subject to the gravity which stars and satellites made of the same primary material used.
Fraunhofer’s lines proved that 73% of the universe is made up of hydrogen and 25% of helium. This was corroborative evidence of the Big Bang. Subatomic research necessitated a medium-intensely hot environment for the production of the hydrogen atom. The first detailed estimate was put forth in 1948 by the work of Gamow and colleagues.
As Gamow suggested, the rapid cooling of the universe from an intensely hot state explained the cooperative production of elements of protons and neutrons and the 73% proportion of hydrogen in the universe. Hydrogen cannot form in the processes taking place inside the stars; the Big Bang cleared the way for the formation of the hydrogen atom and its amount.
EVIDENCE IN THE AMOUNT OF HELIUM
The Big Bang has taught us that helium formed at the very beginning of the universe. At its beginning, the universe was a very hot mixture of protons, neutrons and electrons. As this composition cooled down, nuclear reactions began to occur. Neutrons and protons combined in pairs that joined to form the nucleus of the element helium. Theoretical calculations showed that twenty-five percent of the composition of the universe was made up of helium. Helium can also be produced by the reactions taking place in the stars; however these reactions cannot by themselves account for this amount of helium.
All the observations carried out thus far have confirmed this. For instance, in 1999 American and Ukrainian astronomers used the Multiple Mirror and Keck telescopes to obtain a 24.52% proportion of helium. The Big Bang theory was thus proved once again by these astronomers who had determined this proportion based on their observations of the oldest galaxies. Later, in 2000, the results reached by Canadian astronomers were very close. These studies demonstrated that helium had existed from the very early stages of the universe.
EVIDENCE SCATTERED THROUGHOUT THE UNIVERSE
The Big Bang originated from a single point in the universe and all the matter in the universe originated in a cataclysmic explosion. The Big Bang model suggests that, at its origin, the universe was exceedingly small and hot and that its temperature fell as it expanded. The Big Bang model also provided an explanation for the amount of hydrogen and helium in the universe. We have seen that one of the significant characteristics of cosmic microwave background was its diffusion throughout space. The same result must have been reached with regard to the 73% ratio of hydrogen and 25% of helium. Considering that the elements in question scattered in all directions, the same ratio should prevail throughout the expanding universe.
The results tally with the data the Big Bang theory anticipated and have been demonstrated by the observations made. Hydrogen and helium are the dominating elements in every spot of the universe. Approximately three fourths of the universe consists of hydrogen and one fourth of helium.
EVIDENCE PROVIDED BY DEUTERIUM AND LITHIUM
All the deuterium (one of the three isotopes of hydrogen, the nucleus containing one proton and one neutron) and lithium were formed immediately after the explosion. Processes going on inside the stars cannot form these elements; as a matter of fact, stellar burning gobbles up those elements rather than producing more of these atoms. The Big Bang model explains the raison d’être of deuterium and lithium.
Observations made with the Keck and Hubble telescopes conform exactly to the amounts of deuterium and lithium as suggested by the Big Bang model. Studies of Vanioni Flam, Coc and Casse published in 2000 and research conducted previously confirm this.
Calculations related to the amount of deuterium and lithium in the universe prior to 1994 were made in stars relatively near the earth. After 1994, the masses of gas at a distance of 12 billion light years from our planet (that is billions of years before) were examined. Deuterium and lithium were also present in these. The fact that these elements existed from the first minutes after the Big Bang once more prove the validity of the Big Bang theory.
We can summarize the results as follow:
1. About three-fourths of the universe consists of hydrogen atoms
as suggested by the Big Bang theory.
2. About one-fourth of the universe consists of helium atoms as
suggested by the Big Bang theory.
3. The ratios are prevalent throughout the universe as suggested by
the Big Bang theory.
4. The maximum intense heat required for the formation of the
hydrogen atom is provided by the Big Bang.
5. Helium may form inside the stars, but the 25% helium in the
universe can only be explained by the Big Bang.
6. The stars gobble up the elements like deuterium and lithium;
these elements owe their formation only to the Big Bang.
7. The recent discoveries that succeeded in observing distant (the
most ancient) galaxies and gas clouds and establishing the amounts
of hydrogen, helium, deuterium and lithium prove the primordial
existence of these elements just as suggested by the Big Bang
model.
6. EVIDENCE FROM THE SUB-ATOMIC WORLD TO STARS’ PROGRESSIVE DEVELOPMENT ACCELERATORS OF BILLIONS OF DOLLARS
To gain a better access to the sub-atomic world, accelerator tunnels were constructed to simulate the hot mediums and to increase the velocity of sub-atomic particles. These experimental mediums in which the prominent physicists of the world carry out their research projects are marvels of technology constructed at a very great cost. The most powerful of these are CERN in Geneva, Switzerland, Fermilab in Chicago, USA, and SLAC in San Francisco, USA. The experiments conducted in these tunnels tally with the Big Bang model.
The Big Bang theory postulates that at the beginning, only energy existed; this was followed by the formation of all the subatomic particles as the initial heat gradually cooled down; this, in
turn, was succeeded by the production of gas clouds and periodically of stars. All the stages of formation of the sub-atomic world and stars are explained in terms of the reduction in heat, and in condensation and expansion. The discovery of matter and antimatter, electrons and positrons (that is, the anti-matter of the electron), protons and anti-protons, quarks and anti-quarks and their destruction of each other are explained within the framework of the Big Bang theory. In brief, all the stages of the sub-atomic world, the present sub-atomic state of our universe, are explained in terms of the Big Bang model and the accelerator tunnels mentioned a while ago confirm the model.
THE FIRST THREE MINUTES
About one second after the first explosion, the temperature at every spot in the universe has been computed to have been around ten billion degrees. These results have been obtained by sophisticated
mathematical calculations. Persons who are not particularly interested in physics and mathematics seem at a loss to understand the boldness people display in speaking of the first second of the Big Bang. However, the acclaimed books about the subatomic world explain these phenomena in terms of split seconds. Steven Weinberg, the author of The First Three Minutes (perhaps the most celebrated among its kind) said that we were ready to behold the cosmic phenomenon of the initial evolution of the universe. He said that as the phenomenon at the first seconds of the universe took place at a more rapid rate, it might not be advantageous to represent the sequence of shots in equidistant time intervals like in an ordinary filmstrip. He suggested arranging the speed in parallel with the cooling process of the heat and taking a shot whenever there is a reduction at the rate of 1/3. Weinberg illustrated these stages with six frames. I will try to give a brief account of these six frames in order to illustrate the daring with which the Big Bang model’s mathematical
results have accredited us:
First Frame: The temperature of the universe marked 100 billion Kelvin. The universe was a chaotic structure made of matter and radiation. In this chaotic milieu, every particle was in collision with each other at great speeds. In the first frame, the number of nucleic particles was not so great. There was only one proton or neutron for approximately every billion photons or electron or neutrinos. It is advisable to remember that the time corresponding to the shot was about one percent of a second.
Second Frame: The temperature of the universe fell to 30 billion Kelvin. Just 0.11 seconds had elapsed. The limited number of nuclear particles had not yet integrated to form the nuclei. The ratio of nucleic particles was subjected to a shifting of 38% of
neutrons and 62% of protons.
Third Frame: The temperature fell to 10 billion Kelvin. 1.09 seconds had elapsed since the first frame. The universe was still too hot to allow the integration of neutrons to form the nuclei of atoms. The shifting in the balance of protons and neutrons was 24% neutrons and 76% protons.
Fourth Frame: The temperature was now 3 billion Kelvin. The time that had elapsed since the first frame was 13.82 seconds. Neutrons were being transformed into protons, though at a slower pace: the balance was now 17% neutrons and 83% protons. The universe was cool enough now to allow the formation of nuclei like helium, but the process had not begun as yet.
Fifth Frame: The temperature was 1 billion Kelvin now. A short time after the fifth frame a striking thing occurred. The temperature dropped to a degree at which the nuclei of deuterium (an isotope of the hydrogen element) did not break down. Nevertheless, the number of the nuclei heavier than helium was not considerable. The time elapsed since the first frame was 3 minutes and 46 seconds (Weinberg apologizes for the slight mistake in the title of the book, since the addition of the fraction of 46 seconds to the title might not sound so catchy).
Sixth Frame: The point targeted in the fifth frame was reached and the basic elements had already formed. However, in anticipation of the subsequent phenomena, Weinberg ventured another frame. The temperature was 300 million K, this time. 34 minutes 40 seconds had elapsed since the first frame. The nucleic particles had integrated. But the temperature was still too high to allow stable atoms
PLANCK TIME
We try to understand the phenomena that occurred within the first seconds of the universe explained by the Big Bang model, thanks to the infinitesimal calculation and experiments conducted by particle accelerators. However, it is not possible to say anything about the fraction of time equal to 10 . This fraction of time is called Planck time; as physical laws like the law of gravity are not applicable to this fraction of time, it cannot be defined. Nothing can be said about the 10 K degrees, the temperature of the Planck time.
The Big Bang model has elucidated many things, enabling us to describe in such detail the formation of the universe from sub-atomic world to galaxies within the framework of the expansion of the universe following the decrease of temperature and density succeeding the Planck time. The point at issue now is the extremely small fraction of a second.
The world of science had been deprived of thousands of years from cosmogony, the scientific study of the origin and development of the universe. All the particles from quarks to the formation of gluons, from protons, neutrons and electrons to neutrinos, fit into the Big Bang model of the universe. The antiparticles, their interactions and the evolution to this day conform perfectly to the Big Bang model.
EVOLUTION OF STARS
The Big Bang model’s account of the formation of the subatomic world and stars through an evolutional process is 32 10 saniye -43 seconds confirmed by experiments and observations. Astronomers divide the stars into three categories: namely, first population of stars,
second population of stars and third population of stars. The first population of stars was the first to appear (some make a reverse classification of stars according to their discoveries). The first population of stars is called the “super-giant stars,” as they came about at a period when the elements of the universe were denser. Their lifetime was short as all their elements were dispersed by a big explosion. Theoreticians conclude that few, if any, of these stars may be observed.
The second population of stars has been described as follows within the framework of the evolutionary process of the Big Bang model.
a)These form the largest population of stars.
b)They are denser in particular regions (like the regions where young stars are formed).
c)They should come in both big and small sizes in all mass categories.
These three postulates conform to the recent observations of astronomers. The third population of stars, a category that also includes our sun, was formed from the scattered dust of the second population of stars.
A great many elements, ranging from the carbon and calcium in our bodies to gold and iron, are the products of the second population of stars. This also explains the reason why living beings were created 15 billion years after the creation of the universe. As a matter of fact, an atom like the carbon atom, an element essential for the earth, was the product of the second population of stars.
The evolution of stars has been confirmed by observations, which, in turn, were additional pieces of evidence that sustained the Big Bang theory. The Big Bang model explains the universe by an evolution from the sub-atomic world to the populations of stars; this is a dynamic account of the universe, contrary to the views held for millennia that had sustained the static models of the universe. Observation and experimentation combine to give voice to mathematical calculations, enabling access to the mystery of the universe never before witnessed in such a way in the history of science.