A dominant prevailing theory about the origin of the Universe is the Big Bang model, which was accepted by the scientific community after gathering enough observational evidence and later verifying its predictions. One of the foremost paradoxes thrown open by the Big Bang theory is its idea of the original explosion of all universal matter from a single point. In other words, the theory purports that everything that comprises the universe literally came out of ‘nothing’. Such a premise goes against the basis of scientific understanding and gives credence to Judeo-Christian notion of the beginning of the Universe, whereby the birth point of the Universe is seen as an act of God. For example, “One of the fundamental rules of science is the impossibility of getting something from nothing. This rule appears to place the very moment of creation of the universe outside the realm of the scientific debate and force scientists to treat the existence of the universe as a given.” (Wersinger, 1996, p.9) Keeping aside the implications of this paradox the study of the development of scientific ideas pertaining to the subject is fascinating in itself. The rest of this essay will delve further into the history of ideas on our Universe’s genesis, whether it is closed or open, the reasons for its perpetual expansion, etc.
It is interesting that despite great progress being made in terms of explaining nearly all cosmological phenomena one observes through telescopes, the mystery of the Big Bang continues to preoccupy the scientific community. Further, there is no plausible explanation discovered yet for the explosion itself. There is no rationale devised for explaining the enormous repulsive force that kick-started the universe. And what hampers scientists is the fact that during the time of genesis, the temperatures and matter density were so high that it is impossible to replicate those conditions in a laboratory environment. (Wersinger, 1996, p.9) But incisive forays have been made into later chronological events in the Universe. These discoveries threw up more paradoxes for scientists to confound with. For example,
“In the course of the scientific step-by-step reconstruction of the chronology of the universe, a number of puzzling paradoxes surfaced, of which two are of interest here. The first deals with the strength of the explosion. The push of the Bang was exquisitely well fine-tuned, allowing for the existence of a ) universe with galaxies, stars, planets, and life. Any other push would have meant either a structureless universe or a universe collapsing back onto itself after a brief existence. Why was the Bang so well engineered? The second paradox deals with the large-scale properties of the universe. The extreme large-scale smoothness of the temperature and of the density of matter cannot be explained by the standard Big Bang model.” (Wersinger, 1996, p.9)
Since laboratories cannot replicate the conditions during the Big Bang, scientists resorted to mathematical modelling “relying on fundamental principles of physics and on arguments of simplicity and aesthetics — a route that has been extremely successful in theoretical physics, starting with the discovery of the theory of Relativity by Einstein.” (Wersinger, 1996, p.9) Alternatively, physicists such as Alan Guth (who specializes in elementary particle research) have proposed “a very interesting model for the behavior of the universe when it was a mere 10 sup -35 seconds old, called the inflationary universe. This model resolves our two paradoxes and provides a mechanism for the explosion.” (Fisher, 1999, p.35) There is also the Grand Unified Theory (GUT), first mooted by British physicist James Maxwell, which attempted to unify all known forces of nature into a single theory. Theorists such as Sheldon Glashow, Steven Weinberg, and Abdus Salam have contributed to GUT, which “incorporates both the electroweak and the strong nuclear force into a superforce. The prevailing idea is that when the universe’s temperature was above 10 sup 28 K all forces except gravity were indistinguishable and that the distinct forces we now observe are merely low-temperature manifestations of the superforce.” (Fisher, 1999, p.35) GUT has so far shown tremendous potential in solving the paradoxes associated with the Big Bang model. It’s eventual success would depend on something called the ‘false vacuum’.
Turning now to the age of the Universe, no other instrument has been more useful in measuring it than the Hubble Space Telescope. Truly, one of the major achievements of human ingenuity, the Hubble Telescope has not only brought out the magnificence and splendour of the cosmos, but also helped measure the age of the universe. Scientific progress usually follows a path of small sequential steps that lead more closely to major breakthroughs. And this has been the case with research on the Universe and its age. For example, Nicholas Copernicus, the great Polish astronomer of the late middle ages, discovered the helio-centric nature of our solar system. While there are other flaws in the model proposed by him, this was a major discovery. Subsequently, people like Tycho Brahe and Johannes Kepler have added valuable insights to the working of the cosmos. Yet, the task of deriving reliable distances between objects in the Universe remained arduous. One method that is used by astrophysicists is called the ‘distance ladder’, where
“there exist steps that allow us to estimate distances sequentially from nearby stars to distant galaxies. In the interest of honesty, however, the distance ladder might better be termed the distance “house of cards,” because the reliability of each level depends critically on the reliability of the previous, presumably more secure, level. The Holy Grail at the top of the distance ladder is the Hubble constant, a measure of the universe’s rate of expansion. The inverse of the Hubble constant provides a measure of the age of the universe by mathematically “turning back the clock.”…For nearly all galaxies in the observable universe, the recession velocity is found to be proportional to distance. What does this look like? Nearby galaxies recede slowly and distant galaxies recede quickly, which is the precise signature of an explosion…” (Tyson, 1995, p.72)
It is believed that understanding the age of the universe can help understand the events of the genesis. But the mind-boggling numbers of the age of various galactic bodies highlights the complexity of the project. For example, one of the prominent galaxies that resembles the Milky Way is measured to be 700 kiloparsecs (similar to lightyears) away. The nearest quasar, named 3C273, is approximately 600 megaparsecs away. The horizon of the observable universe, which the Hubble telescope could barely penetrate is about four gigaparsecs away. All this makes calculations pertaining to the events of the genesis very sensitive – even a minor error in the factored values can totally dismantle a theory. (Tyson, 1995, p.72)
In order to find out the age of the universe (which can provide insights on the events of its origins), an understanding of the cosmic mass density is required. But unfortunately, this number is difficult to pin-down, as it is given to fluctuations. Based on the mass density and the visual information provided by the Hubble telescope, scientists can predict whether the universe will continue its path of expansion and end up in the ‘big chill’; or it collapses into a ‘big squeeze’. Hence, a lot bears upon the accuracy of these numbers. The estimated mass density of the universe ranges “from a small fraction of the critical amount needed to ultimately arrest the cosmic expansion (as inferred from observations) to the critical density itself (as wished for by many theorists). Across this range, a Hubble constant of 80 provides for a universe that is anywhere from about 12 billion down to 8 billion years old.” (Tyson, 1995, p.72)
One of the major challenges in studying the Universe is the propensity for physical constants to change in value. Constants such as the speed of light in a vacuum and the masses of elementary particles, etc are noted to change with time. Although the changes are miniscule, the implications can be very profound, for they could validate or disprove an accepted theory. New findings reveal that the “the ratio between the mass of the proton and that of the electron–a number known as mu-might have decreased by about two-thousandths of a percent in the past 12 billion years. The evidence for the change in the constant, which has a current value of 1,836.153, emerged from light-absorption patterns of hydrogen molecules, the scientists report in the April 21 Physical Review Letters.” (Weiss, 2006, p.259) Once proved correct, this discovery could revolutionize our understanding of the Universe, its age and the distances between its farthest objects.