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Since the beginning of human civilization, people have always questioned the origins of their existence and the creation of the universe. Where did it all come from? How was it created? These are the questions that plagued ancient societies and are those which still puzzle scientists today. Cosmology, the study of the large scale structure and evolution of the universe, is the branch of science which has evolved from these questions. Within this field of study, the Big Bang theory has become the most prevalent theory, because the majority of evidence from a variety of different investigations make it extremely likely that something like the Big Bang occurred.
The Big Bang theory of cosmology assumes that the universe began from a singular state of infinite density. As Joseph Silk defines the Big Bang theory, “it is a model of the universe in which space-time began with an initial singularity and subsequently expands” (Cosmic Enigmas, 55). In 1927, Georges Lemaitre used equations to devise a cosmological theory that incorporated the concept that the universe has been expanding from an explosive moment of creation. However, the term Big Bang, as a name for the initial cataclysmic event, was taken by two men named George Gamow and R.A. Alpher due to their discovery of background radiation, a low-temperature radiation that pervades the universe at microwave wavelengths. Its source is now believed to have been the extremely hot fireball with which the universe began, according to the Big Bang theory. Since its initial introduction, much evidence has helped to strengthen its case, and other theories have been added to it, such as the Inflationary theory. “This theory seeks to account for the physical events which took place in the very first moments of creation. In short, the Big Bang theory is one which incorporates other theories in its attempt to explain the evolution of the universe” (Boschckle, 99).
To begin with a study of the history of the Big Bang theory, one must define the term cosmology, the subject and process of inquiry that the Big Bang theory falls under. Cosmology is the study of the large-scale structure and evolution of the universe. Some of the issues which are considered to be cosmological include those referring to how the universe began, how and why life evolved throughout time, and how the universe is ordered. Today the central issues in cosmology are explained through the widely accepted framework of the Big Bang theory, which basically states that the universe began in a fiery explosion which occurred about 15 million years ago
Modern cosmology was born when Albert Einstein developed his General Theory of Relativity in 1915, and his first cosmological paper in 1917, when Einstein attempted to make the equations of relativity fit together with the incorrect belief that the universe was stable and static, with no beginning nor an end. Einstein's theory of gravitation and general relativity identify gravity with the curvature of space-time and the four-dimensional manifold that consists of the three space dimensions combined with time. Any event can be described in terms of its path and location in space-time. In particular, the light from distant galaxies logically follows the shortest possible path, called a geodesic. The manner by which one looks back in time is by geodesics; galaxies are almost like time machines, with the light from most distant galaxies traveling through space-time since before the earth was even formed, 4.6 billion years ago. The most distant galaxies are at a distance of ten billion light years, basically providing a look-back in time of ten billion light years as well.
Einstein's theory of relativity received solid confirmation in 1919, when the deflection of light from distant stars by the sun was measured during a total eclipse. The cosmological implications of Einstein's theory of relativity began to receive intensive examination. Einstein wrote his first cosmological paper in 1917, in which he developed a model of cosmology in which he hypothesized a cosmic repulsion force that was characterized by a new term, the cosmological constant, in his gravitational field equations. The role of this cosmic repulsion was to balance gravity and yield a static model of the Universe. However, it turned out that the cosmological constant itself which Einstein had postulated was unnecessary because there was a cosmological solution to Einstein's equations that he had overlooked.
The idea of the Big Bang and an expanding universe which challenged Einstein's idea of a static and unchanging universe, came primarily from a Russian meteorologist, Alexander Friedmann, and a Belgian cleric and mathematician, Georges Lemaitre. The formulation and prediction of a Big Bang explanation for the universe was remarkable because both men formulated that theory of cosmology without any firm observational evidence for universal expansion. Both men, in different years, independently discovered the solutions to Einstein's equations of gravitation which described an expanding universe, discarding Einstein's cosmological constant and his perception of a static universe. Friedmann, in 1922, and Lemaitre, in 1927, demonstrated that the universe could be in a large scale expansion. To avoid collapse, expansion of the universe balanced gravitational attraction. The expansion could either continue forever, or eventually reverse into a phase of contraction. A principle implication of their theory was that the matter content of the universe implied that space was not necessarily Euclidean or analogous to the flatness of a plane in a two-dimensional analogy, but could be curved like the surface of a sphere (with a positive curvature) or a hyperboloid (negative curvature). Since the surface of a sphere is closed and finite while a hyperboloid is open and infinite, it can be inferred that a universe with high matter density should be closed, finite, positively curved and should eventually collapse, while a universe with low matter density should be open, infinite, and negatively curved, expanding indefinitely.
Edwin Hubble, a famed American astronomer of the 1920's, discovered a linear relation between distance to a remote galaxy and its redshift in 1929 which provided exciting evidence supporting the idea of the ever expanding universe which came from the Friedmann-Lemaitre model. Hubble’s discovery was influenced substantially by the work of a Dutch astronomer, William de Sitter, who in 1917 hypothesized that the universe possessed the peculiar property that the light from the most distant regions became progressively reddened as the distance increased. “Hubble's redshift is due to a Doppler shift of light from a galaxy which is receding, and provides a credible explanation for Hubble's law, that the distance of galaxies from us is linearly proportional to their redshift and therefore linearly proportional to their relative velocity of recession, if it is space itself that is expanding as it had been predicted by Friedmann and Lemaitre” (Coles, 104). So basically, galaxies and bodies that are twice as far from us than another, move twice as fast. This idea indicates that it has taken every galaxy the same amount of time to move from a common point of origin to its current position, wherever that might be.
In 1931, Einstein and de Sitter himself, proposed that the universe could be at a critical density and spatially flat. Such a universe would be infinite, with the geometry of a plane, Euclidean geometry, and expanding indefinitely. Einstein and de Sitter developed an expanding cosmology in which the spatial geometry resembles that of ordinary Euclidean space, improving upon the Friedmann-Lemaitre model of the universe. Simply put, the open and closed curved Friedmann-Lemaitre universes and the Einstein-de Sitter model of the universe form the core of the Big Bang hypothesis. In each of these models, the universe expands from a smaller volume to its present scale, with a continuing process of expansion and enlargement.
The term Big Bang for these theories was coined by the Russian born U.S. nuclear physicist George Gamow in 1946. He was one of the foremost advocates for this theory for the creation of the universe, supporting the work of Einstein, Friedmann, Lemaitre, and Hubble. Gamow attempted to explain the distribution of chemical elements throughout the universe through a spontaneous thermonuclear reaction. He also proposed that in the beginning of the Big Bang, the universe consisted of a primordial substance called ylem. “This ylem was a gas of neutrons which was at extremely high temperatures exceeding 10 billion degrees” (Gribbin, 204). Because the neutrons existed in this free state, they began decaying into protons, electrons, and neutrinos. The result was a boiling sea of neutrons and protons which merged together to form heavier and heavier elements. In Gamow's perception, all of the elements in the entire universe formed in this manner during the earliest twenty minutes of the Big Bang. This hypothesis, attempting to account for the origin of helium and hydrogen in the universe, was submitted by Gamow and his partner, Ralph Alpher in 1948.
Then in a follow up paper, Gamow and Alpher wrote that after the universe was created in a great fiery explosion, as the universe expanded, the radiation would not have persisted but would have been steadily diluted. This would explain the necessary cooling of the universe. But the most important part of this second paper was the prediction of background radiation, a tangible clue to the actual Big Bang. Although in the 1940's there was no technological way to detect such a faint afterglow, scientists of later decades would be able to prove what Gamow had hypothesized.
As cosmology and the Big Bang theory gained acceptance by the scientific community, solid, scientific evidence was found which supported the Big Bang and Gamow's theory of background radiation. In the spring of 1964, Arno Penzias and Robert Wilson, two researchers at Bell Laboratories, while measuring noise levels from the sky, unexpectedly discovered a signal of microwave radiation which had a temperature equivalent of about 3.5 degrees Kelvin. The signal was coming from all directions of the sky. The explanation for this signal was that it was a detection of leftover radiation from the creation of the universe, the Big Bang. This conclusion was reached because of the isotropic and blackbody nature of this radiation. Since isotropic means the radiation at the wavelength was equally intense all over the visible sky, it can be inferred that that is exactly what one should expect if left over radiation came from the Big Bang, that since it occurred everywhere simultaneously, the afterglow should be uniform across the heavens. This was a smoking gun giving more strength to the Big Bang theory of the creation of the universe and proving Gamow's hypothesis.
More recently, cosmic microwaves were detected which seemingly originated at the farthest, outer reaches of the universe. These microwaves were incredibly uniform, indicating the homogeneity of the early stages in the creation of the universe. “The COBE satellite of NASA which detected these microwaves also discovered changes in temperature and other factors which supported previous calculations based upon the assumptions of the Big Bang theory” (Lerner, 160). Although, it may never be known for sure whether the Big Bang was the definite manner of creation for the universe, modern scientific thought and evidence, such as that of the COBE satellite, indicate that the Big Bang theory is at the very least, an extremely plausible one.
According to the Big Bang theory, the universe began with one large explosion, which took place about 15 to 20 billion years ago. We now refer to this explosion that began the universe as the 'Big Bang' and it is from this theory that we are able to examine the evolution of the universe from the milliseconds of creation to the creation of galaxies, and from the formation of planets to the presence of life on earth. Because almost all astronomical phenomena can be explained entirely within the context of the Big Bang, or if not completely, can be explained to a greater degree than any other mode, this model of the universe has become the most widely accepted up to this point. However, within the framework of the Big Bang theory, there are several different models of the universe.
The standard model of the Big Bang theory takes three possibilities into consideration . The first one is the open Friedmann-Lemaitre theory on the universe in which hyperbolically curved space is destined to expand forever. The second theory is the closed Friedmann-Lemaitre theory on the universe in which spherically curved space is destined to collapse again. The third one is the Einstein-de-Sitter theory which calculates that the flat space of the universe is destined to continually expand as well. Although these three models do not differ greatly in the initial and beginning fazes of the evolution of the universe, they do differ in their later fazes and as one can see, they predict very different futures for our universe.
These three possible theories within the standard model of the Big Bang cosmology all originate from the initial gigantic explosion from which the universe was created. Although conditions in the universe previous to the Big Bang can only be speculated upon, scientists believe that it must have been an atmosphere of extremely high density and temperature as well as irregularity in order for such an event to have taken place. At the moment of the 'Big Bang' all of this dense matter began to expand. It is due to the variety of evidence which supports this cosmology that most cosmologists and astronomers agree with this framework.
One of the most interesting thoughts which arises out of this framework, is that the universe was not always in the state which we see it currently. Probably the most astounding fact is that we are now in a position to describe the universe as it existed during most of the first second of existence.
In its early stages, according the Big Bang theory, the universe was in thermal equilibrium. A searing light pervaded all locations and traveled in every direction, with the characteristics and qualities of a blackbody at exceedingly high temperatures. Early on in creation, the temperature was in the trillions of degrees because it was in a highly compressed, primordial state. At this extremely early stage of creation, particles of opposite charge freely moved around independently of one another, in a state of matter called a plasma. As the space expanded according the Big Bang theory from a single point of origin, the wavelengths of light stretched out as well. Likewise, the expansion of the space stretched the wavelengths shifting the extremely high temperature blackbody spectrum to that of a lower temperature. Blue light shifted to the cooler red light region, and the universe cooled. As the universe cooled, certain forms of nuclei, definite amounts of helium, hydrogen, and lithium were formed, as well as other forms of elementary particles. About 1,000,000 years later, and almost 15 billion years ago, the universe became cool enough for atoms to finally form.
Soon after the formation of atoms and the subsequent attraction of particles of opposite charges, another natural process began. The expanding new materials began to come together in clumps. As the universe expanded, matter was being brought together in these clumps by the force of attraction in gravity. Within each clump, the gravitational forces continued to operate, drawing large clouds of gases together to form nebulae. Eventually, the clumps and clouds of gas would form stars through a process known as fusion.
A gas cloud had little choice but to collapse and fragment into what we now know as stars. Only the random motion of its atoms provides a pressure that can resist gravity for only a very short time, with atoms colliding, radiating because of the presence of heavy atoms such as carbon, losing their kinetic energy of motion, and eventually causing a cool down and a collapse. As the gas clouds collapse into little clumps; these clumps merge together into larger, mixed fragments, and grew by accreting gas from their surroundings. This collapsing gas soon became sufficiently dense to begin radiating energy from atomic collisions, and thus the first stars were born.
Over time many of the star clusters dissolved because of disruptive gravitational forces exerted by other clouds, and a galaxy emerged which resembled the Milky Way. The most prominent feature of this early galaxy was a rotating disk of stars and gas clouds, along with a compact central spheroid shape of stars which developed from those collapsing gas clouds. Five billion more years would go by before one of these interstellar clouds would birth our solar system, condensed from the remnants of earlier stars. Finally, simply put, chemical processes would occur to link atoms, which were billions of years in the making from the origin of the universe, together to form molecules, and then eventually complicated solids and liquids, and finally bringing us to where we are now.
With our ability to observe other regions, not just the optical region, we have discovered much evidence that supports the Big Bang theory. “Probably the most persuasive evidence for this theory is the presence of cosmic microwave background radiation, which can only be detected by radio telescopes” (Smith, 55). Cosmic microwave background radiation is diffuse isotropic radiation whose spectrum is that of a blackbody at 3 degrees Kelvin and consequently is most intense in the microwave region of the spectrum. This radiation is thought to come from the cooled residue of the initial explosion from which the universe evolved. Because microwaves are of shorter wavelengths, only several centimeters wide, and are thus not in the optical window, we are not able to directly observe these. Microwave radiation also does not usually produce heat, except at extremely high intensity, making it difficult to detect. However, our entire universe is a great source of these microwaves and it was not until the production of a small radio horn for satellite communication, created in 1965 at Bell Laboratories in Holmdel, New Jersey that radiation was detected.
The discovery of cosmic microwave background radiation, was significant because it fit in with George Gamow's theory that the elements of the universe had been created 5 minutes after the 'Big Bang' and thus primordial radiation should be scattered across the universe. He also hypothesized that due to expansion, the temperature of radiation should have cooled to about 5 degrees above 0. When scientists detected this radiation it became evident that it contained a high degree of uniformity which proves its origins are from the farthest points of the universe. Joseph Silk states the reasoning behind this assumption clearly in his book entitled, The Big Bang:
Any radiation produced near the sun, in our galaxy, or even in nearby galaxies would undoubtedly be unevenly distributed. Therefore, we assume that the sources of the radiation are evenly distributed throughout space. Suppose we divide the universe into a large number of concentric and equally spaced spherical shells, all centered on and enclosing the earth. In this case, the amount of radiation coming from sources within any pair of adjacent shells is the same, because the area of a sphere increases with distance in just the same way as the intensity of the radiation decreases. A uniform background radiation must come mostly from the distant parts of the universe, where the majority of the sources are found. Very little of the radiation could originate in our local region of space, and any isotopic background radiation must be produced at cosmological distances” (56).
Cosmic microwave background radiation has also been found to have almost a perfect blackbody radiation, meaning that the intensity distribution of its radiation is that of a blackbody. Its temperature now is about 3 degrees Kelvin, inferring that it is very cold. This fits in very well with the notion that the universe has been expanding. Indeed, if the blackbody radiation is traced backward in time, it becomes hotter and hotter until it reaches the conditions to create blackbody radiation; a state of perfect equilibrium between radiation and matter. Evidence is also provided from small deviations from the blackbody spectrum of about 5 degrees. They provide important information on the small imperfections of the Big Bang, which are responsible for the structure of the universe. This discovery of cosmic microwave background radiation is probably the most significant evidence that supports the Big Bang theory.
Radio Galaxies, galaxies that are extremely luminous at radio wavelengths, have also provided support for the Big Bang theory. No other cosmological theory has been able to incorporate radio galaxies into their theory, because it has been found that these galaxies have been evolving through time. Unlike other of its rival theories, such as the Steady State theory, evolution of the universe is the central concept to the Big Bang theory.
Numerous radio galaxies are apparent throughout the universe. They often have a very intense region of radio emission near the center of the galaxy and are sometimes accompanied by a halo of bright radio emission extending throughout the galaxy. The radio emission from radio galaxies seems to be very highly polarized, which has indicated to scientists that its origin is the radio radiation of very energetic electrons. These electrons moved at nearly the speed of light and spiraled in the weak magnetic field of the galaxy. It is thought that they were the result of some very violent event, in which an amount of energy equivalent to the total annihilation of up to ten million stars was released.
It is thought that radio galaxies have evolved from stronger to weaker sources on the space-time scale of the big bang cosmology. This is due to the detection of the strongest and most abundant radio sources in the outer most parts of the universe. We observe them now as they once appeared long ago when the amount of their radiation was at its highest level. This finding corresponds to the theory that the universe has been continually expanding from a hot, dense, explosion, because the outer radiation sources all have higher radiation levels than do closer ones.
Other evidence for the Big Bang theory came when Edwin Hubble was able to demonstrate the relationship between a galaxy's red shift and its distance. “He was only able to do this with the knowledge of the distances of some stars, which was only possible with his 1929 discovery of the exact distance of a star in the Andromeda Galaxy” (Smoot 67).
The nature of such galaxies was also not yet understood. The spiral nebulae, as vast, remote collections of suns, were finally understood in 1912 by Vesto Slipher. In his 1912 study, Slipher obtained spectra of 41 galaxies and from the red shift in these spectra, the velocities of the galaxies were calculated. For those moving toward us, galaxies had velocities of 300 km/sec and for those moving away, had a velocity of 1,800 km/sec. After a correction was made to allow for solar motion around the center of The Galaxy, all the velocities of distant galaxies were found to be receding from us. With the knowledge of both these findings, Hubble then was able to demonstrate a relationship between a galaxy's red shift and its distance.
The red shift found in galaxies is simply a Doppler effect observed in the galaxy's spectrum, indicating its recessional velocity. The farther away a galaxy is, the greater is its red shift. In 1929 a linear relationship between the recession velocity (v) and the distance (r) of observed galaxies where the constant of proportionality (H). This is now known as Hubble's Constant. By 1936 this relationship had been broadened to distances as large as several hundred million light-years. The expansion of the universe and the general correctness of Einstein's Theory of General Relativity had been established.
With the discovery of radio galaxies as well as red shifts for objects in the universe, quasars were detected. Quasars are the most luminous known objects in the universe, some of them having luminosities of more than a thousand times greater than that of our own Milky Way galaxy. Some quasars discovered in the late 1980s and early 1990s have a luminosities of more than 4.5, making them the most distant objects yet found in the universe. This means that their spectral lines are shifted to wavelengths more than 4 times greater than normal, which implies that objects are moving away from Earth at 93 percent of the velocity of light.
”Some quasars appear to be located within clusters of galaxies and show the same red shift as the galaxies, while others have appeared to lie almost in the same line of sight with galaxies having different red shifts” (Trefil, 99). If such interaction between such quasars and galaxies exist, this would imply that the quasars in question are not as far away as some had thought. However, most astronomers accept the concept that quasars do lie at their apparent cosmological distances and that these are extremely active nuclei from distant galaxies.
“To date, a few hundred quasars are known, and the maximum red shift is more than 4, corresponding to a recession velocity of more than 93 percent of the velocity of light” (Verner, 88).. Although the nature of quasars and their role in the evolution of the universe are still unclear, current astronomical theory suggests that the objects are the brilliant and extremely active nuclei of galaxies at an early stage of evolution, and that they lie at the far limits of an expanding universe.
Other evidence has given astronomers a good idea that the origin of the universe began with something like a big bang. The presence of a large number of light elements throughout the universe's atmosphere is also a good indicator that something like the Big Bang occurred. The Big Bang theory predicts that light elements were put together in the first few moments of the initial explosion. This prediction is based on the very high temperatures and densities believed to have been in place during the first minutes of the explosion, which is extremely conducive to the synthesis of light elements. The presence of an element called Deuterium is another reason scientists believe that light elements originated from the big bang. The prediction that light elements were synthesized in the first minutes of the big bang has been confirmed by the vast quantities of light elements present in the universe.
Deuterium is an extremely fragile element, which consists of helium and 1 isotope of hydrogen, has no other plausible explanation of its origin. Deuterium, symbol D, is the stable, non-radioactive isotope of hydrogen and has an atomic weight of 2.014. It is known that Deuterium is only destroyed in stars, but not produced and is thus present only in the interstellar matter that has not yet formed into stars. Deuterium is found here because it is unable to survive the high temperatures at the centers of stars. Its presence in the interstellar medium agrees with the prediction of the Big Bang.
Other elements such as hydrogen, helium, and lithium found in abundance in the universe are also good evidence that light elements were formed in the first few minutes of the big bang. The amount of helium in relationship to hydrogen, remains surprisingly constant from galaxy to galaxy, which shows its cosmological origin. Greater amounts of the element lithium found in the oldest stars than younger ones, also indicates that these light elements were created in the big bang. The amount of lithium does not correspond to the amount of heavier metal elements, but its amounts are instead found to climax in oldest stars. This shows that lithium has very early and pre-galactic origins.
Evidence such at the presence and location of light elements, the existence of cosmic microwave background radiation, quasars, and radio galaxies all give good much support to the Big Bang theory. Most cosmologists now accept the Big Bang theory rather than the rival Steady-State theory, and are attempting to account for the bizarre physical events that would have been involved in the very first moments of the Big Bang. This is because most of the information and data that astronomers and physicists have assembled, fits into this model of the universe. Unlike other models, it takes into account the concept of evolution and change in the universe, which much of the evidence seems to suggest has taken place and will continue to take place.
As with many other scientific hypotheses, the Big Bang theory is not completely infallible. Although much current evidence supports the Big Bang theory of the creation of the universe, there is still some level of uncertainty surrounding it. In fact, there are four fundamental problems associated with the Big bang. These problems include the question of: why there is so little antimatter in the universe, how the galaxies could have formed in such a short period of time, the problem of expansion or contraction, and more philosophically, what happened prior to the initial instant of creation? These questions bring up important issues relating to the universe which have not been properly answered by the Big Bang theory.
In 1932, Carl Anderson, a physicist at the California Institute of Technology, discovered a new type of particle called a positron, which had the same mass of an electron, but instead of a negative charge, had a positive charge. This was the first example of antimatter to be seen in a laboratory setting.
Antimatter basically is a form of matter that, at the particle level, consists of a particle whose mass is equal to that of a normal particle but carries opposite electrical charges. There are other important properties of antimatter as well. Antimatter anihilates whenever it comes in contact with ordinary matter and also can be created in energetic reactions between elementary particles. Also, every particle has a corresponding antiparticle. If we have a collection of particles and certain anti-particles at a very high temperature, we would expect a balance to occur between these processes of annihilation and creation. Every time a pair annihilates each other, such as an electron (particle) and a positron (anti-particle), another pair would be created in a collision at a different place. But as the temperature falls, creation cannot proceed any longer with annihilation since there is not enough energy to produce the mass of the pair of particles. Then the balance dissipates and annihilation occurs until all the particles or antiparticles are used up entirely.
The issue that the Big Bang theory has a hard time resolving is that in this particle period which scientists refer to, taking place approximately thirteen minutes after the Big Bang, both annihilation and creation of particles involved pairs, so therefore, for every particle which was created or destroyed, a corresponding process occurred for antiparticles as well. But one of the interesting facts about the earth is that there is very little antimatter at all, almost none. Satellites and planetary probes which have explored the galaxy return with the same verdict that there is no antimatter anywhere. The question is how to explain this complete imbalance between matter and antimatter, not only on Earth but also in our galaxy.
Explanations for this imbalance include hypotheses that before the particle era of the Big Bang there was already an imbalance between matter and antimatter, either by the universe starting out with more matter, antimatter being segregated to another region of the universe, or a process occurring before the particle period creating matter disproportionately to antimatter. Advances in astronomy have given the most credence to the theory that some process did occur that created matter before the particle period of creation.
The process of the formation of galaxies is directly connected to the creation of atoms, about 500,000 years after the Big Bang. Before the formation of atoms, continuous collisions between radioactive photons and particles in early plasma, in which photons bounced off of particles, created a pressure that prevented matter from collecting into galaxy sized conglomerations. But as soon as atoms formed, the radiation (photons) was no longer scattered by matter. The consequences of this action is that the radiation was free to expand without interference and that this radiation no longer exerted pressure on the matter. It was finally possible for matter to coalesce into what we know as galaxies today.
To form galaxies, normal atomic motion would guarantee that although the universe may have been spread out uniformly since the moment of spontaneous creation, eventually two atoms would have found themselves in close proximity to one another. These two atoms would then have exerted a somewhat stronger than usual gravitational force on neighboring atoms, pulling them in. Then as the atomic cluster grows, the gravitational pull will get stronger and stronger continuing to pull in atoms, aggregating around the original point, until all available material is pulled in. It is this type of collection of matter which we know call galaxies.
The problem which occurs when discussing the Big Bang theory is not whether this galactic creation fits in with the theory, but that it would take too long for a few atoms to grow into an awesome galactic mass, for this to fit in with the time of the Big Bang. One must remember that this process of gathering and aggregation is occurring while the universe is undergoing a rapid expansion. If the collections of matter do not reach a critical size fast enough, then the universal expansion will carry the rest of the material out of their reach before enough mass has accumulated to from a galaxy. The essential problem is that the initial part of the process, building up from two or more atoms through random atomic motion, to an aggregate lump of material is quite long. With the Big Bang causing an extremely rapid process of creation and expansion and a scattering of atoms and materials, it seems impossible for galaxies to be formed considering the amount of time necessary for this creation.
The only solution for this problem of the formation of the galaxies within the confines of the Big Bang is that there must be some unknown process that would form aggregations (which would later become galaxies) before the formation of atoms. Any other possible solution would be contrary to the scientific laws which govern the Big Bang theory. The problem with this potential solution is that there are no known processes that would provide for the clumping together of matter during the particle era, before the formation of atoms.
When postulating their Big Bang theories, Friedmann and Lemaitre stated that the expansion of the Universe balanced gravitational attraction to avoid a complete collapse. These scientists concluded that this expansion could either continue forever or eventually reverse into a phase of contraction. With the picture of the expanding universe coming from the Big Bang, one must wonder if this seemingly endless expansion will reverse itself and lead to a process of universal contraction.
“The answer to this query depends on the amount of mass in the universe, which is hard to gauge since all the matter in the universe is not necessarily visible to us” (Zieger, 99). If there is enough mass, then the gravitational force that it exerts will be sufficient to slow down and eventually stop the recession of galaxies. Whether there is or is not enough mass is up to question, but current observations do indicate that the universe is very nearly flat, meaning that there is almost enough mass to bring the expansion to a stop, but not quite enough. It seems from these observations that the mass of the universe, and thereby the expansive or contractive state of the universe, is unknowable entirely. But although this problem of flatness is unsolvable, it is the kind of problem that would not shake a physicist's faith in the Big Bang theory. If the antimatter problem was unexplainable, that would be a different matter.
An interesting question that comes to mind when dealing with the Big Bang theory is; if the Big Bang created the universe as we know it, then what, if anything, existed before it? A modern speculation for many contemporary scientists and physicists is that the present expansion may be one cycle of many which this closed universe has undergone. But in reality, it is impossible to know what could have existed or occurred before the Big Bang scientifically. We can only speculate philosophically about what could possibly have been before the initial moment of creation. It is remarkable that although modern science can determine what occurred one minute after the big bang, that it is impossible to determine what existed or occurred before. We face the prospect of never knowing the answer to this and other related questions regarding creation of the universe.
One can see that the Big Bang theory of creation is by no means an air-tight, completely secure theory. Questions such as that of the formation of galaxies, and antimatter can be hypothesized about but never completely explained. Problems with this widely accepted theory do exist as one can see, but the dearth of evidence may indicate that the Big Bang theory is more accurate than not.
Although the Big Bang theory does not yet explain everything about the evolution of the universe, it does indeed explain much. With the advances in modern technology, much convincing evidence has been discovered adding further credibility to this framework of the universe. Unlike other models such as the Steady State theory, the Big Bang theory makes evolution and change the central concept of its cosmology. As astronomers and physicists gain more information from more technical instruments such as the COBE space satellite and the Hubble Space Craft, they will undoubtedly discover more elements of the universe that will contribute to our understanding of its evolution. Smaller questions such as the lack of antimatter, the creation of galaxies, and the possibilites of universal contraction still puzzle scientists. However, the biggest question that they have yet to determine is whether the universe will expand indefinitely or will ultimately collapse upon itself and perhaps repeat the process forever.
WORKS CITED
Boschke, F.L. Creation. New York: Comit Books, 1988.
Coles, Peter. The Big Bang New York: Bantam Books, 1992.
Gribbin, John. The Expanding Universe New York: Random House, 1994.
Lerner, Eric. In Search of the Big Bang San Fransico: W.H. Freeman Co., 1980.
Silk, Joseph. The Big Bang San Fransico: W.H. Freeman Co., 1982.
Silk, Joseph. Cosmic Enigmas. Woodbury, N.Y.: The American Institute of Physics, 1994.
Smith, Robert. The Big Bang. Cambridge: Cambridge University, 1982.
Smoot, George. Wrinkles In The Bang. New York: Morrow & Co., 1993.
Trefil, Scott. A Moment In Time. New York: Charles Scriber’s Sons, 1995.
Verner, Nick. The Big Bang. New York: Scott & Sons, 1996.
Zieger, Victor. At The Beginning…. New York: Preston Co., 1994.
Bibliography
WORKS CITED
Boschke, F.L. Creation. New York: Comit Books, 1988.
Coles, Peter. The Big Bang New York: Bantam Books, 1992.
Gribbin, John. The Expanding Universe New York: Random House, 1994.
Lerner, Eric. In Search of the Big Bang San Fransico: W.H. Freeman Co., 1980.
Silk, Joseph. The Big Bang San Fransico: W.H. Freeman Co., 1982.
Silk, Joseph. Cosmic Enigmas. Woodbury, N.Y.: The American Institute of Physics, 1994.
Smith, Robert. The Big Bang. Cambridge: Cambridge University, 1982.
Smoot, George. Wrinkles In The Bang. New York: Morrow & Co., 1993.
Trefil, Scott. A Moment In Time. New York: Charles Scriber’s Sons, 1995.
Verner, Nick. The Big Bang. New York: Scott & Sons, 1996.
Zieger, Victor. At The Beginning…. New York: Preston Co., 1994.
Word Count: 6452
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