Fifteen billion years ago, the entirety of our universe was compressed into the confines of an atomic nucleus. This is the moment before creation when space and time did not exist. According to the prevailing cosmological models that explain our universe, a biggest explosion ever made trillions of degrees in temperature on any measurement scale, which was definitely intense. It created not only fundamental subatomic particles and then matter and energy, but space and time itself. (Beck) Cosmology theorists combined with the observations of their astronomy colleagues have been able to reconstruct the primordial chronology of events known as the “Big Bang.” (Bennett)
The origin of the Big Bang theory can be credited to Edwin Hubble. Hubble made the observation that the universe is continuously expanding. He discovered that a galaxies velocity is proportional to its distance.
Galaxies that are twice as far from us move twice as fast. Another consequence is that the universe is expanding in every direction. This observation means that it has taken every galaxy the same amount of time to move from a common starting position to its current position. The Big Bang provided for the foundation of the universe. Hubble’s observations provided for the foundation of the Big Bang theory. (Shellard)
“Since the Big Bang, the universe has been continuously expanding and, therefore, there has been more and more distance between clusters of galaxies. This phenomenon of galaxies moving farther away from each other is known as the red shift. As light from distant galaxies approach earth there is an increase of space between earth and the galaxy, which leads to wavelengths being stretched.” (Bennett)
In addition to the understanding of the velocity of galaxies emanating from a single point, there is further evidence for the Big Bang. In 1964, two astronomers, Arno Penzias and Robert Wilson, in an attempt to detect microwaves from outer space, inadvertently discovered a noise of extraterrestrial origin. The noise did not seem to emanate from one location but instead, it came from all directions at once. It became obvious that what they heard was radiation from the farthest reaches of the universe which had been left over from the Big Bang. This discovery of the radioactive aftermath of the initial explosion lent much credence to the Big Bang theory. (Beck)
“Even more recently, NASA's COBE satellite was able to detect cosmic microwaves emanating from the outer reaches of the universe. Cosmic Microwave Backgrounds are sometimes called the CBR, for Cosmic Background Radiation, although this is really a more general term that includes other cosmological backgrounds, eg infra-red, radio, x-ray, gravity-wave, neutrino. NASA's COBE (Cosmic Background Explorer) satellite was developed to measure the difference infrared and cosmic microwave background radiation from the early Universe to the limits set by there astrophysical environment.” (Shellard)
COBE was launched on November 18, 1989 and carried three instruments: DIRBE (the Diffuse Infrared Experiment) to search for and measure the cosmic infrared background radiation, DMR (Differential Microwave Radiometers) to map the cosmic microwave background radiation precisely, and FIRAS (Far-Inferred Absolute Spectrophotometer) to compare the spectrum of the cosmic microwave background radiation with that from a precise blackbody. These microwaves were remarkably uniform which illustrated the homogeneity of the early stages of the universe. However, the satellite also discovered that as the universe began to cool and was still expanding, small fluctuations began to exist due to temperature differences. These flucuatuations verified prior calculations of the possible cooling and development of the universe just fractions of a second after its creation. These fluctuations in the universe provided a more detailed description of the first moments after the Big Bang. (Shellard)
The Big Bang theory provides a viable solution to one of the most pressing questions of all time. It is important to understand, however, that the theory itself is constantly being revised. As more observations are made and more research conducted, the Big Bang theory becomes more complete and our knowledge of the origins of the universe is more substantial.
Immediately after the Big Bang, as one might imagine, the universe was tremendously hot as a result of particles of both matter and antimatter rushing apart in all directions. As it began to cool, at around 10^-43 seconds, which is about half a millionth of a second. After creation, there existed an almost equal yet asymmetrical amount of matter and antimatter. As these two materials are created together, they collide and destroy one another creating pure energy. Fortunately for us, there was a lack of balance in favor of matter. As a direct result of an excess of about one part per billion, the universe was able to mature in a way favorable for matter to persist. When the universe first began to expand, this discrepancy grew larger. The particles which began to dominate were those of matter. (Beck)
As the universe expanded further, and thus cooled, common particles began to form. These particles are called baryons and include photons, neutrinos, electrons and quarks. “They would become the building blocks of matter and life as we know it. These little atoms are just bouncing around every where. During the baryon genesis period there were no recognizable heavy particles such as protons or neutrons because of the still intense heat. At this moment, there was only a Quark Soup. As the universe began to cool and expand even more, we begin to understand more clearly what exactly happened.” (Beck)
After the universe had cooled to about 3000 billion degrees Kelvin, a radical transition began which has been likened to the phase transition of water turning to ice. Composite particles such as protons and neutrons, called hadrons, became the common state of matter after this transition. (Beck)
After about one to three minutes had passed since the creation of the universe, protons and neutrons began to react with each other to form deuterium, an isotope of hydrogen. Deuterium, or heavy hydrogen, soon collected another neutron to form tritium. Rapidly following this reaction was the addition of another proton which produced a helium nucleus. Scientists believe that there was one helium nucleus for every ten protons within the first three minutes of the universe. After further cooling, these excess protons would be able to capture an electron to create common hydrogen. Consequently, the universe today is observed to contain one helium atom for every ten or eleven atoms of hydrogen. (Shellard)
While it is true that much of this information is speculative, as the universe ages we are able to become increasingly confident in our knowledge of its history. By studying the way in which the universe exists today it is possible to learn a great deal about its past. Through finding answers to these modern questions, it is possible to trace their role in the universe back to the Big Bang.
In conclusion, the “Big Bang” is one of a few theories on how we were created. With more and more years of study, we come closer to finding out, how the universe was actually created. With technology advancing every day, we are getting to the point, to make a solid solution on how we are today.
Work Cited
E.P.S. Shellard (Cambridge). The COMOS Tour. 1997. 8 Oct. 2003
http://www.damtp.cam.ac.uk/user/gr/public/bb_home.html
Beth Beck. The Big Bang Theory. 1997. 8 Oct. 2003
http://liftoff.msfc.nasa.gov/academy/universe/b_bang.html
Charles Bennett. WMAP Cosmology 101: Big Bang Theory. 2003. Oct. 2003
http://map.gsfc.nasa.gov/m_uni/uni_101bb1.html
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